Colours for Violin Varnish A Survey of Materials for Use in the Varnishing of Musical Instruments Pip Seymour Lee Press, London Zocd) ONE WEEK LQAN‘The Role of Colour in Violin Vamishing ‘The availability of pigments and dyes for use in violin varnishes duting the period 1600-1800 differs vastiy to the methods of supply available to makers and restorers today. Local sources ‘were often used for colouring matter, although some materials were imported. On a general Jevel, colours, resins and oils, as used in varnish were bought through apothecaries (the equivalent to modern-day pharmacies). Some colours, such as the earth pigments and plant- based dyes, would be sourced locally. As 2 consequence, it is nigh impossible today to replicate the same materials as used during the 17th and 18th centuries, as methods of procuring materials have changed. as have processing methods. However, some common Colouring materials which equate to those available in the 17th and 18th centuries are today available through specialist suppliers of artists’ materials. Because more technical and historical information relating to violin-making has become available in recent years, it is now possible to match modem day colour samples to those used previously. ‘As a painter, one of the first concepts that T came across as a student was the principle of glazing with oil colours. While there are differences in terms of resolution, aims and Embitions between easel painting and the use of varnishes onto wooden musical instruments, it is nevertheless true that both painter and violinmaker are attempting to achieve a glowing coloured paint film onto a specific surface. In the case of oil painting, we artists strive to lay down even, slightly glossy films of oil colour onto a priming which has a lite bit of absorbency (the Classic oil painting ground can be a combination of gypsum and lead white ‘mulled into linseed oil and let down with turpentine. The linen fabric is first “sized” with a solution of animal skin glue to reduce absorbency of the painting fabric. The resultant painting ground has a degree of absorbency but also flexibility). With regard to the ‘Yvamiching of violins, the support is always rigid (wood) and the painting ground is often a thin, simple coating of animal glue size. Over this basic and more or less neutral ground/support, layers of coloured varnish are applied, to build up a translucent “glaze”, usually derived from pigments or dyestuffs with a warm tinge. From a technical standpoint, it is always more successful to apply multiple thin/fine layers of paint, than laying down a single, thick application. Jn relation to glazing with oil paint (and this can be similarly applied to application of varnish), it is extremely useful to work ‘with fine, thin layers of paint/vamish, which are slowly built up to achieve a harmonious Whole. Our understanding of paint technique has slowly emerged, largely through scientific researche: analysis of paint layers, examination of the structure of pigment particles and so on. From my perspective, as a painter, ] am more interested in the poetic, intuitive use of colour in painting. The methods by which artists lay down glazes/ paint layers is never scientific, always intuitive and frequently random. ‘Although many violin-makers prepare varnishes according to recipes based on historical texts, this is largely done on an ad-hoc basis: rarely does the violinmaker prepare varnishes according to scientific stricture. In order to make e paint layer or varnish layer work to the ‘satisfaction of the practitioner, iis often the case that intuition takes over from rationale. It is in this spirit that 1] hope violin-makers will read this article and be able to take information relevant to their practice, ‘The principle of “glazing” can be said to be common to both easel painting and the application of varnish to musical instruments. Whereas modem painters take tube oil colours ‘and admix them with oil-resin paint mediums to create luminous translucent glazes, its true that before the invention of the collapsible metal tube in the 1840s, artists had a much closer relationship to the materials they used. The preparation of paints was an integral part of the process of picture-making, almost a ritual component of the day’s work As a consequence, paints were composed from direct mixtures of pigments into binding media (e.g. linseed oil). These simple oil paints were then applied directly to the painting ground: there were no effective means to store paints, so such paints were always made and then used. It is clear that such ofl paints would differ from day to day in terms af colour strength and viscosity, depending on the mood and application of the maker, It is very likely that makers preparing, colours for violin varnish would work in a similar manner, recipes would be followed t© some extent, but exactness would not necessarily be consistent. In some senses, this is whatmakes the world of violin-making so interesting and baffling: talented (but mostly unknown) individuals, working in relative isolation, in an intuitive, day-by-day context, achieving individual, idiosyncratic resnlts. ‘The most important facet to the hand-manufacturing of ofl colours by artists is that such paints hardly ever included the types of filler/extender material which are found in modem Gay ofl paints. This is why violin-makers should never used tube of] colours for tinting varnish. Such paints always contain additives such as filler (e.g. blanc fix, alumina hydrate); stabilising agents (e.g. beeswax, aluminium stearate) and siccatives (e.g. cobalt dries). ‘All these additives are included in modern paints to enable the paint paste to stay stable in the tube, achieve optimum “brushing” qualities (according to the philosophy of the manufacturer), give uniform drying and consistent sheen, etc. It is not advised to use such paints for adding into varnishes, because the filler agents tend to cloud the paint film: glazes ‘will not necessarily have clarity. Also, drying agents may cause the paint/varnish film to ‘become over-brite in a relatively short space of time. ‘Tf-we go back (pre-1840), indeed if we go back to the realm of Venetian painting (late 1500s- early 1600s), we find painters applying glazes which are based on oil-resin paint mediums, tinted with very small additions of transparent pigments. Such oll-resin mediums were often derived from mixtures of mastic resin, sun-thickened linseed or walnut oil, plus balsams such as venice turpentine. Many violin-makers will be familiar with such materials from hristorical recipes for varnish. The exact formulae for the paint mediums used by artists is a rmatier for science: what should be very clear is that there is a cross-over in terms of the types of materials used by painters and by violin-makers. Rather than give a complex list of historical recipes for varnish in this text, Ihave presented a simple list of typical varnish ingredients, with some information on solubility with various solvents. This should provide a starting point in terms of varnish-making. To simplify matters, we can identify two distinct types of varnish: 1. Oil-Resin Varnish 2 Spirit Varnish Oil-Resin Varnish ‘Varnishes tend to be based on natural tree resins which are formed into a liquid solution through immersion into volatile solvents such as turpentine. By tradition, varnishes are manufactured during spring and summer, in dry, moisture-free conditions. When humidity is present in the atmosphere, varnishes tend to give out a cloudy, rather than dear varnish film. This phenomenon is known as “blooming”: in some instances, this blooming effect is not seen in the varnish film when-first applied. As a consequence, in damp, humid conditions (Le. northern Europe), successful varnish-making can be rather difficult ‘As with all natural resin-based varnishes, in the initial stage of dissolving, it is useful to stir the contents vigarously, to help start the solving process. It may also be useful to place the container holding the varnish ingredients into a warm water bath, to induce the early stage of solving. Excessive heat can of course prove detrimental to the final varnish, although some resins, such as amber can only ever be fused//solved at extremely high temperatures. ‘Simple recipe for oil-resin varnish: Mastic resin 100g (pies waste wlleey anmstor anal ane ceo Distilled turpentine 300m! Choose distilled or double rectified turpentine. “At start of solving process, place container into a warm water bath and stir for 15-30 minutes. Leave contents to stand for 2-3 days, stir at regular intervals. Strain through muslin to remove impurities.‘Take 75m! of the resultant mastic varnish and combine with 75ml venice turpentine, along ‘with 150ml stand oil. Immerse the container in a warm water bath to improve flowing characteristic. Dilute further with turpentine as required. Make tests onto flat, glue-sized sheets of raw sycamore veneer to determine the correct level of gloss, viscosity, etc. ‘This combination of mastic, venice turpentine, with stand oil is « slight variation from the paint/varnish mediums of the 1600s, in that modern venice turpentine is normally presented fas a very thick, honey-like consistency. This level of viscosity is very different from earlier supplies of venice turpentine, which would have tended to be viscous yet flowing and fhuid in-character. Today, we can counter this by slightly heating the balsam (place in a warm ‘water bath before using), to gain a flowing consistency. Stand oil is linseed ofl which has been heated in a vacuum. This process partially oxidises the oil, making it slighty faster drying than linseed oil but also, and crucially, it takes on a self- levelling character, thereby losing brushmarks. Partial oxidisation also means that it tends to yellow (darken) less than regular refined linseed oil. Some makers prefer to produce their own thickened linseed oil by taking cold-pressed linseed oil and exposing it to sunlight and heat from sunlight over a period of time, so that it thickens up slightly. Itis always necessary ‘when thickening oils this way to keep it open to air - when the oil is closed to air, it will not thicken successfully. The exposure of the oil to direct sunlight for a certain time period also produces a paler colour of oil: the sunlight bleaches the yellow to a pale, straw colour. The length of time of exposure depends on tive location. For example, the best time may be assumed to be summer. This is not always the case: in Munich for example, the best time period is during March, when that part of southern Germany receives clear, alpine sunlight In northem Europe, where light tends to be filtered through cloud, it will inevitably take longer for oil to thicken up. Some recipes call for the inclusion of a lead-based pigment (massicot/litharge) into the oil during this period of exposure, to promote quick-drying (lead-based pigments have 2 catalytic effect on vegetable oils). Oil which is thickened by cooking with lead-based drier is referred to as “black oil” due to its heavy, dark brown-black colour. Sometimes, black oil is admixed with a;natural resin such as mastic during the cooking stages. With copal resins, the resin is first heated so that it forms a solution: oil and/or warm turpentine is then added to the warmed solution to ereate copal-oil varnish. Preparation of colour into oil-resin varnish ‘The oil-resin varnish can be used as a binding agent for pigment, or, it can be added later, after the pigment has been first mulled to form a simple paint with oil. In relation to paint ‘technique, the Venetian masters (e.g, Titian) would have simply taken pigment added to an oil-resin medium, to achieve glassy, transparent glaze layers. In some cases however, it is ‘thought that artists firt ground the pigment into a paint paste, using a drying vegetable off (eg. walnut oil, linseed oil), before adding into the oil-resin varnish. In this instance, the varnish is used to draw the colour out in practical terms, the pigment-oil paint paste is easier to prepare first, then later introduce to the oil-resin varnish. This is because the paint paste will have been mulled to a uniform consistency, where all the pigment particles are coated in oil, thereby producing a more even paint film, where individual particles cannot be seen. This is especially important when working with granular pigments such as those derived from earth deposits. Earth pigments tend to be rather irregular in terms of particle size and ‘therefore require a litle more mixing than perhaps the lake pigments derived from plant sources. Such lake colours are effectively dyes, which have been struck onto a transparent/translucent substrate such as alum. In effect. their grittiness or otherwise is controlled by the degree of grittiness of the substrate onto which they are stuck As a consequence, such plant based lake colours tend to be rather soft in terms of their physical structure when compared to earth pigments. Tt should be clear that certain pigments will require extra mixing, while others require lite or no mixing to achieve a smooth, grit-free appearance when applied into « paint/vamish binder. 10Mulling of Pigments ‘As already stated, we have two possible methods for colouring oil-resin varnishes. Firstly, it is possibie to introduce pigment straight into the oil-resin varnish. This often gives perfectly acceptable results, especially with pigments that are easy to prepare. The:second method, whereby a paint paste is made using a binder (e.g. walnut oil), the resultant paint paste is ‘then combined with the oil-resin varnish and duly applied to the instrument To begin with it is suggested that the second method is adopted, which is more thorough and ‘will provide smoother paint/varnish layers. Once you have worked with pigment and various binders/ varnishes, it should be possible, with certain pigments, to skip the paint- paste step and work directly with pigment into the varnish. Malling or milling of pigments is crucial to the realisation of thoroughly mixed paint. The purpose of this mulling is not to break down the particle size of the pigment rather, itis the achievernent of a thorough mixing between pigment and binder. In effect, this process results in each pigment particle being coated with oil thus the oiled particles stick to each other in a regular, cohesive manner. If one simply mixed pigment and linseed oil together using a paletie knife on a glass slab, the resultant mixture may appear slightly grainy and also slightly matt in appearance. The longer the pigment and binder are mixed together, the smoother and more regular the mixture becomes. This process is best achieved by taking a glass muller, or glass runner, and mulling the pigment and oil together in a figure of eight motion. The glass slab onto which one works should be sandblasted to have a slight toothy grain. This stops pigment particles from dancing across the slab. The glass muller should also hhave & sand-blasted face, so that similarly, pigments dispersed into oil are caught on the toothy surface and do not slide about on the surface. This provides the maker with some control remember that gaining control of these raw materials is crucial to their processing, Some pigments require “ wetting” before they will mix readily into linseed oil. Typically, ‘modern synthetic organic pigments (e.g. alizarin crimson) have such a fine particle size, that they need to be carefully prepared, as at first they tend to resist combination with most binders. This ” wetting” is sometimes done with a tiny addition of solvent (eg. double rectified turpentine) but is better done by choosing cold-pressed oils which have a high acid content: Such oils tend to accept pigment more readily than refined oils. When using oil for hand-preparation of colours, it is always preferable to use cold-pressed oils, because they tend to show less brushmarks (they are self-levelling) and their colour is more consistent in terms of ageing. Refined oils tend to be bleached: over time, this bleaching rectifies itself and oil tums a dark orange-brown colour. This darkening process is less dramatic with cold- pressed oils, because the initial colour is always darker at the outset typically, a warm yellow-orange colour. As already mentioned, the cold-pressed oils have a high acid content, Which allows pigments to be readily dispersed. the best oils are those made from flax plants in northern Europe such as those grown in the Low Countries, the Baltic states and northern Germany. Makers should try samples of each type available on the market to discern their relative colour, viscosity and suitability for varnish making. During milling of pigment nto oil, the mixture turns from a slightly matt, grainy 9 to that of a sleck, glossy paint paste. The exact time required will change from pigment to pigment and is only understood through practice and experience. The pigments mentioned in this text may be available in different formats. For example, earth pigments vary wildly in quality, according to their source and the manner in which they have been processed. Often, earth pigments are slightly gritty and require extra mulling to achieve smooth paint pastes. It may be useful with some gritty pigments to grind them toa finer consistency prior to use, in a pestle and mortar, then put through a fine sieve, so that only the finest particles are utilised. ‘The basic paint paste is then admixed with the ofl-resin varnish and is ready for se. Itis best to prepare each colour and apply it, rather than try to store in empty tubes or glass jars. Hand-made paints tend to settle out after a short time and then become virtually unusable‘Best practice is to prepare the paint paste with the oil-resin varnish, then dilute with solvent (eg. distilled /double rectified turpentine) to the desired consistency. Before adding any solvent, try warming the mixture, by placing a contniner of the coloured “paint/ varnish” into ‘2 warm water bath. When ‘warmed through, the mixture will flow more readily and may require little or no addition of solvent to produce e fine, clear, fat layer. ‘Over-heating of the mixture can be problematic: as the vamish layer dries, so it shrinks slightly, which may cause cracking at a Jater stage, or the phenomenon of “creeping” upon drying. This creeping occurs as the varnish film dries off: creeping, or rather shrinking back from where the layer has been applied. The application of such materials is always a matter of dexterity: with experience, one begins to understand how materials behave when treated in specific ways. To begin with itis useful to make mistakes and Jearn by them. It seems to be true that any material, when heated too much, behaves in a manner which is not necessarily required! ‘The application of vamish is another area of confusion. Some makers opt for fine, soft hair brushes, such as those made with sable, ox or squirrel. However, it is also possible to use fingers, lint-free cotton cloth, or the ball of the hand. Indeed, old texts on paint technique often mention the application of glazes and varnishes by rubbing with the ball of the hand. This process drives the varnish layer into the paint surface. With violin varnishes, the structure is slighty different, in that previously applied layers tend to be non-absorbent. In practice, one needs to experiment lo reach the desired effect. Because modem oil colours contain a number of fillers and additives, they are practically unusable for colouring varnish. These fillers tend to add cloudiness to the resultant colour. Additionally, drying agents may have been added, which can alter the expected drying rates, of the chosen colour. lis better practice fo hand-prepare colours into the chosen binder. As one might imagine, each pigment used in the colouring of medium/varnish will have individual characteristics which govern how they behave. One of the most important aspects relates to the particle size and structure of the pigment used. Larger, irregular particle will need more binding agent, because the oil (or whichever binder) has further to travel in order to completcly coat the pigment particle, to form a unified paint/varnish film. Some confusion exists in relation to this. For paint-making, one always looks for a regular, even paint film, that can be brushed out flat, is self-levelling, etc. When adding small inclusions of pigment into liquid paint medium or varnishes, the pigments are more or less scattered at random into the liquid binder/medium/vamish. As such, there may be no coherent paint film: the pigment particles are loosely distributed into the liquid binder/medium/vamish. Some of the particles may “cluster” (ie. they group together), or they may be dispersed at random through the liquid binder/medium/vamish. Itis far more likely that pigments are randomly dispersed, than carefully milled and uniformly distributed in the liquid binder/medium/varnish, in the case of violin varnish. Cross-sections of historical paint and/or coloured varnishes tend to uphold. this: it is rare, or pethaps even impossible for transparent coloured paint/varnish films to yield regular, homogenised and equally distributed particles. With modem oil paints, this ‘may be the case, but hand-milied paints tend to give less-consistent results. 1 common practice among painters was to hand-mill (:vull) pigments on a marble slab, using a porphyry or glass muller, this may not have been the case with violin-makers. While there ‘would be a case for using pigments with a small particle size, these pigments, especially in the case of coarse, raw earth pigments would tend to have a variety of particle sizes. Whereas modem pigments are finely divided into mesh sizes (according to the size of mesh used when sieving), hand-prepared pigments are never exactly the same from batch to batch, or even within one batch. For example, rew sienne is a typical warm yellow earth pigment, often used for glazes, given its relative translucency. Sienna has a high silice content, which renders it quite transparent when applied as an oil glaze. However, being derived from earth deposits, sienna may contain impurities but may also consist of rough, irregular particles. In best practice, the finer particles can be gotten by simply leaving the pulverised earth to stand 2in water for a few days: all the fine particles stay at the top of the pigment sludge; the larger ppieces fall to the botiom. The finer size particles are removed and dried out, before being ground with oil, etc, This “washing” of pigment also removes plant debris and other impurities. It is probable that many makers would prepare their own colours like this, or procure colours from others who used similar techniques. There are no hard and fast rules and certainly no standards that can be adopted as being “regular”, It is wiser to look at the whole process as being idiosyncratic. As a result, varnish layers may be quite contrary in their construction, even when considering work done by one maker over a period of time. ‘When irregular pigments such as raw sienna are applied to wood, itis the concentration of colour in the liquid binder/medium/varnish that governs its appearance. It makes sense that such pigments are not over-ground when mixing with the binder. If the particles are kept loose and dissociated with each other, more light passes through the varnish film and more ‘transparency is achieved. It is difficull to be more precise in respect to this, except to say that for each pigment, the appearance will differ. the important thing is to make tests before applying, to see how the particles lay down in the liquid binder /medium/varnish and how much of a colouring effect they give. It may be a surprise to find that hardly any pigment is required and also, that a combination of more than one pigment into one layer may prove useful. Spirit Varnish Spirit varnishes were originally prepared from spirits of wine. Today, shellac, solved into industrial methylated spirits (water-free), provides a basic spirit varnish, which is. then admixed with pigments or soluble dyes. Spirit varnish can also refer to varnishes produced from other alcohol soluble resin, such as sandarac, or varnishes which contain a higher proportion of alcohol to other solvent types (i.e. remains soluble only in alcohol). Preparation of colour into spirit varnish ‘Alcohol based varnishes are readily resoluble. As a consequence, overlaying of multiple spirit varnishes requires considerable dexterity. The alcohol contained in the varnish tends to “pick-up” in the previous layer, causing creeping of colour from one layer to another. As a consequence, spirit varnishes are sometimes used as a sandwich or isolating layers between oil varnishes, of as a final coating over an oil varnish. Their appears to be no one method of producing a varnish onto a musical instrament and, as already mentioned, experimentation is crucial Spirit varnishes can be used with both pigments and dyes. Transparent pigments work very ‘well into spirit vanish and the warm colouring of shellac varnish is often very helpful Indeed, because shellac is available in a number of colours (lemon, orange, red, burgundy, ttc), some makers rely solely on the colouring property of the varnish itself to achieve the desired effect. The same can be seen with oil varnishes, where certain balsams (e.g. venice ine, violin rosin) already have e warm tinge. Students can learn much by preparing the different naturally coloured shellacs into varnish and seeing how they work by overlaying. After five or six coats of orange shellac varnish, cone builds a colour which seems reasonably acceptable as a final colouring varnish. Shellac varnish is prepared by solving the shellac flakes into alcohol and leaving to steep for a fow days, As with all varnish-making, the initial solving process is quickened when the container is placed into a warm water bath at the beginning of the process and stirred for a few minutes. When the shellac has completely dissolved, strain the resulting varnish through fine muslin, s0 removing any impurities or residue, Shellac flakes tend to include a tiny wax residue, which can impart a cloudy effect to the varnish. Its advisable to sieve the solution through a fine mesh to gein the clearest varnish. Before putting pigment with spirit varnish, it is advised to pre-wet the pigment with a little alcohol. This allows the pigment to readily disperse into the varnish ‘When using dyestuffs which are soluble in alcohol, before adding to vamish, grind the powdered dye with a little alcohol: enough to make a stiff paste, where the grains of the 3yestuff have dissolved to form a slick, smooth consistency. This paste is then introduced into the shellac varnish and should remain totally solved and clear, providing a perfectly ‘transparent coloured varnish. Shellac varnish is best applied using soft brushes at a relatively dilute concentration: the inclusion of a litle extra alcohol helps Keep the varnish wet and workable for a longer period. Varnish which is thicker (containing less alcohol) will dry quicker on the brush and ‘be more difficult to manipulate. ‘Varnish Media: an Overview of the Basic Properties of Oils, Resins, Balsams, Gums, Solvents for Violin Varnish ‘There are innumerable recipes for creating varnishes, based on combinations of resins formed into solution by solvent action, or by heat (“running”), then admixed with various drying vegetable oils. Some resins cannot be incorporated into oil vamishes (Le. varnishes which are diluted by turpentine) and which can only be used with spirit (alcohol) vamishes. Itis beyond the scope of this book to examine in detail the properties of varnish media. By contrast, a short list of resins, ofls and other materials is included, to provide a reasonable starting point Drying Vegetable Oils ‘The cooking of vegetable oils tends to leave such oils both thicker and darker in colour than in the raw state. This darkening effect can be beneficial in the preparation of varnishes, imparting a warm glow to the varnish film. Remember that cooked oils may darken appreciably more with age than uncooked oils. In general, these oils can be diluted with turpentine to create thinner paint/vamnish films. It is advised to use turpentine over other solvents, because it leaves a slightly greasy residue in the varnish film and evaporates evenly and slowly, leaving clean, fat varnish films. These vegetable oils dry through a process of oxidisation: the oil film takes in oxygen then slowly expels oxygen, eventually forming a harden mass. This process can take many months or even years in the case of thicker varnish/paint films. Some oils are classed as “non- drying” because they remain soft and fresh: however when use din very small additions to other ingredients, they are sometimes incorporated into varnish recipes. Cold Pressed Linseed Oil Thin films dry in 3-4 days. Golden yellow colour, less likely to darken than refined linseed oils. Cold-pressed oils tend to show brush marks less than with refined linseed oil. Dilutes ‘with turpentine. Can contain mucilaginous deposits, which should be removed before use. To separate (clarify) oils, take « quantity of fuller’s earth (e.g. 10% to volume of ofl), drop into container with the oil and leave to settle out. The fuller’s earth drags any waste/mucilage in the oil to the bottom of the container. Carefully pour out the clarified liquid. The best qualities are derived from flax seeds of plants grown in Northern Europe (North Sea coasts, Baltic States, Scandinavia), where light filters evenly through low cloud. Such oils have « high acid content, which allows for easy mixing with powdered pigments. Refined Linseed Oil (Oil which is expressed by heat is referred to as “refined” or “purified”, Such oils yield golden yellow-orange colour, tending towards green-brown in some cases. This dark colour is rectified by bleaching prior to packing, to provide an ofl with a very pale, straw colour. In time, this pale colour reverts to dark, sometimes appreciably darker than cold-pressed oils. This feature is common to most drying vegetable oils: cold pressed oils may appear darker ‘when first used, but upon ageing, they tend to darken less than refined oils. Refined oils tend to reveal brush strokes and as 2 consequence may not be applicable to use in varnish films, where self-levelling paint/ varnish films are required. Refined oils tend to ry at a quicker rate than cold-pressed oilsPoppy oil A slow drying oil (pechaps 7-12 days for a thin film), with « pale colour. Poppy ofl tends to leave a matt varnish/paint film, with a slightly frosty character (i. it slightly clouds the paint film). Poppy oil consequently tends to attract dirt and dust, as is the case with all matt Paint films. It may be useful as an addition in varnishes to impart sofiness or @ matt appearance, in combination with other oils or resins. Walnut Oil Sold in both cold-pressed and heat-refined forms. The best type is cold-pressed from ripe walnuts, with a pale yellow-orange colour. Although walnut oil creates a relatively glossy, hard and brittle paint film, when applied to rigid supports such as wood, it should be quite reliable. The cold-pressed oil should be procured when fresh and may turn rancid if not used quickly. Walnut oil thickened by sunlight in conjunction with air provides a viscous, honey- like oil with a glossy sheen: an ideal varnish ingredient. As with poppy oil, the drying time is slow (1-2 weeks). In general, the refined poppy and walnut oil will dry faster than the cold- pressed varieties. ‘Remember that oils which have been thickened by either heat or exposure to heat and air will also tend to dry quickly. Safflower Oil A pale, slow drying oil Like poppy oil it imparts mat fms. Lavender Oi! Distilled from lavender flowers, especially in the south of France (e.g, Mont Blanc). This oil hhas a solvent action and as such can be used to dissolve natural tree resins such as mastic and sandarac. Lavender oil will mix readily with both alcohol and turpentine. As such, it can be ‘used to cross-implement the use of resins and drying oils which are not normally compatible. Lavender oil slows down the drying rate of the varnish/ paint film: in fact it is often used in oil painting as a retarder. Choose fresh stock as it can become foul-smelling when left around too long and especially when exposed to air, when it thickens to a sticky resinous syrup. As with spike lavender oil, this is manifested in a change of colour, from almost colourless to pale yellow and sometimes green-yellow. Spike Lavender Oil Distilled from a broad-leaved variety of lavender, particular to the Iberian peninsula. It has similar properties to turpentine, although it has a tendency to oxidise (thicken up, leaving a horrid, sticky gum residue). Choose fresh supplies always! Because it has a more viscous consistency when compared to turpentine, it is very useful for solving resins and tends to evaporate extremely slowly from paint/vamish films. When used, varnish layers need to be left to completely dry out before over painting. Oil of Cloves Distilled from the flowers of the clove tree, this ofl is very slow to dry and is an active solvent. Its sometimes used to impart very slow, even evaporation of a varnish/ paint layer, although the very slow drying rate (perhaps one month or more) can Jead to problems in overpainting, The strong solvent action of clove oil may also disturb previous layers, especially in the case of softer resins, or varnish layers which have only just dried. It may also appreciably darken colour values upon drying. Castor O21 Although castor oil is e non-drying oil, itis sometimes used to impart flexibility to otherwise brittle resins. Because itis soluble in alcohol, the drying vegetable oils and volatile oll such as turpentine, it can be added to most varnishes. Over use will leave the Varnish layer sticky and soft.Stand Of When linseed oil is heated in a vacuum, a thicker, heavy-bodied oil is created, known as stand oil. It resembles and takes on some of the properties of naturally sun-thickened linseed oil in that it is pale in colour, self-levelling and less prone to darken than linseed oil. It ends to impart flexibility into paint films and is often added for this purpose in oil varnishes. ‘Natural Resins Many types of tree, especially coniferous trees yield sticky resinous liquids that, when hardened form into “resin” material. When such resins are immersed in solvent, they form solutions, which provide the glassy, transparent films common to violin varnishes. In truth, ‘many recipes are based on fusions of different resins, in association with drying vegetable oils to provide varnish coatings. In picture conservation, varnishes are required to be as pale and colourless as possible, be resoluble with solvent and remain relatively flexible over time. In the context of varnishing Violins, resins used in the manufacture of varnishes may be more desirable if they are darker in colour, especially if they are a warm colour. Because the support (wood) is rigid, the question of flexibility is less important. In fact some of the softer resins such as mastic, propolis and sandarac may be too flexible on their own and are often admixed with harder resin types. Resins are often used to impart glossiness to varnish films: by careful dilution and admixture with oils, ec, the exact gloss and depth of the varnish coating can be adjusted as required. Mastic Tree resin from Chios, a Greck island (but also from other sources in Greece and North Africa) derived from a species of Pistaccio. The bark is incised in springtime and the resultant sap collects into tiny beads and then hardens. These characteristic hardened “tears” of pale yellow mastic resin are then harvested in late summer. Mastic dissolves into alcohol readily. With turpentine and spike oil, also lavender oil, the resin dissolves readily when placed in a ‘warm water bath at the beginning of the solving process. Subsequent stirring is also advised to give a quick-forming resin solution. Mastic is a soft resin with some elasticity. While in solution and mixed with other resins, it aids the adhesion of other resins to the support Varnish is prepared in dry conditions, without humidity or damp cold air, which could induce “blooming” into the vernish film. This manifests itself as a slight clouding in the dried varnish film which cannot be removed. As a consequence, varnish making in northern Europe is best done on warm spring and summer days. Sandarac Derived from the sap of a variety of pine found in north Africa, especially Morocco, sandarac isa pale, straw coloured resin, formed in the shape of long droplets. The sap is harvested from the tree bark by incision, the hardened droplets are later gathered. The resin fractures easily and usually has a slightly dusty, grainy powder surface. Sandarac can be solved into alcohol completely to make a spirit varnish which is softer (less friable) when compared to shellac. Itcan also be partially solved into warm turpentine (the residue must be filtered) but will dissolve completely into spike lavender oil, allowing it to be used with various drying vegetable oils. By contrast to mastic, sandarac is slightly arder (more brittle) as ¢ varnish coating. Colophony Where pine tress are used for turpentine production, colophony is the term used to describe the solid residue left behind when turpentine is distilled. This resin has a very high acid content and is extremely brittle. When incorporated into vamishes, it tends to be very prone to cracking or splintering, As consequence it is used sparingly, despite the fact that its warm golden colour is appealing. Colophony dissolves readily into turpentine but also with alcohol. Some darker varieties may be desirable as additions to violin varnish. 16Violin Rosin Colophony is sometimes also known as “rosin”. When pine tree sap is collected as a liquid sap, it is taken as a viscous liquid and thence distilled to create turpentine (spirits of turpentine, distilled turpentine, rectified turpentine, etc). In the viscous, liquid form, it is sometimes referred to as “violin rosin”. As such it can be a useful component in varnish recipes. The lquid sap contains both solvent and resin, thereby it is slightly more flexible than the dried-up colophony resin. It is sometimes used as a base material for violin varnish, ‘where other resins and oils, etc are added to the Violin rosin. The dark red-orange of violin rosin makes an ideal starting point and, despite its inherent brittleness upon drying, when combined with more fiexible materials it may be serviceable. Copal A family of tree resins derived from fossilised, or partially fossilised plant material. Copals fare hard and give glossy coatings. Congo Copal is the most highly desired of this resin group, dug from fossilised trees, typically lying beneath swamps. The difficulties of extraction, coupled with the fact that such resins are no longer required by industry (where ‘modem alicyd resins are now used) mean that fossilised copal resins are now hard to find on the market In order to put copal into solution, it is first “run”, by heating until it melts and forms @ solution. Into this hot bath of resin, it can be fused with linseed oil, or other drying oils, to make a thick syrup. This not mixture can be diluted with turpentine to the desired consistency. Kauri Copal is a partially fossilised resin from New Zealand, which is soluble in alcohol. ‘Once a solution is formed it can be rendered more flexible by admixing with warmed solutions of venice turpentine. Manila Copal, confusingly, is not from fossilised resin. Il derives from a type of conifer native to Manila and actually imparts a softish varnish film when solved into alcohol to make a spirit vanish. As such it offers a more flexible alternative to shellac varnishes, with a paler colour. Amber “Another type of fossil resin, amber is collected from open pits or from shore deposits in the Baltic states, where it is often washed up along the shoreline. Amber is a solid resin, and ‘extremely hard and glassy. As a consequence, it is very difficult to form into a solution. It ‘melts at 290°C and in this state can be solved into linseed oil to form a permanent liquid varnish. Because of the very high temperature, the utensils used in manufackure are likely to be unusable afterwards, being caked in hard, cooled resin. The vapours given off are rather noxious and the buming of amber should always be done out of doors and with necessary protective equipment. Spike lavender oil is sometimes added to the linseed oil to help keep the resin liquid but this tends to leaves a varnish coating with a longer drying (curing) time. Some recipes call for amber pieces to be brought to melt point, then left to cool. Once cold, the resin is pulverised to a fine grain powder, then remelted and fused with linseed or walnut oil Myshh ‘This resin contains a portion of natural rubber, which requires removal before use as @ ‘amish. Derived from a species of shrub common to Ethiopia and Somalia, myrth is solved in alcohol to make a spirit varnish. The resin is first crushed to a powder using a pestle and mortar, then left to stand for a week in alcohol. It is occasionally stirred to improve the solving process. At the end of this period, the resinous part will have formed a solution, while the residue of rubber will collect at the bottom of the container. Carefully filter before ‘The resultant varnish is clear but has @ pronounced golden brown colour. Gum Benzoin Benzoin is derived from almond trees and always coniains impurities within the sap. It provides a very soft resin, soluble in alcohol only. To remove the debris in the sap, the solved resin must be strained before use, left to stand and then strained once again. ”Gum Elemi Elemi, the best types of which are procured from Manila, is collected as a sofi-resinous mass, containing many impurities. If left exposed to.air, it hardens and is then unusable. It canbe dissolved into warm alcohol or turpentine to form 2 solution which is then strained to gain « straw coloured (but slightly cloudy) liquid. Elemi is very soft and is often incorporated into varnish recipes to increase flexibility. However, over-use may provide varnish films which are rather sticky and retains a certain cloudiness. ‘Tree Balsams ‘A number of trees yields sap residues which are collected in this form and Kept as thick viscous liquids. These tree balsams, or “oleo-resins” are highly prized for their clear films and brilliant sheen. ‘Venice Turpentine From the European Larch, this tree balsam (it is collected as a liquid sap and used as such) is often used as an additive to varnishes to impart flexibility and extra gloss. Good varieties do not discolour because they do not contain abietic acid (as is the case with colophony and some other pine resins, which take on a dark yellow-orange colour that can become progressively darker with age). As a consequence, venice turpentine is highly prized by oil painters (especially so in the golden period of Venetian painting, hence the name of the material). The best quality of venice turpentine is collected from larch trees in the Austrian ‘Tyrol. The best sap is located at the heart of the tree: it is collected by drilling into the centre of the tree. This perhaps explains the high cost of the material. Small amounts of venice turpentine are added to other ingredients to impart luminosity and brilliance, to gain an cenamel-like surface. It may also be used to impart flexibility to harder resins. Modern venice turpentine tends to be very thick in consistency and requires to be placed in a warm water bath to gain fluidity, from which point it can be diluted with a little turpentine to gain a permanently fluid formulation. In earlier times, venice turpentine was probably less viscous and easier to brush out without warming. Sometimes this material is sold under the name “Venetian Turpentine”. This can sometimes be the same material, but more commonly, it infers that the true venice turpentine has been adulterated with colophony, or violin rosin, thereby giving a more brittle film upon drying, Strasbourg “Silver-Fir” Turpentine Often mentioned in historic texts, the so-called “Silver-Fir” or “Strasbourg Turpentine” is similar to venice turpentine but has a paler colour. It is sourced from silver-fir trees in the ‘Vosges region but also, and perhaps more importantly, it has also been derived from silver fir trees in the Halian Tyrol, often mentioned in texts as “olio d’Abezzo", The balsam is collected from oponings in the bark caused by natural blistering, Itis used in a similar way to venice turpentine and is particularly useful for coating pigments which are susceptible to degrading when exposed to atmospheric conditions: the balsam envelopes the pigment, thereby offering protection. Copaiva Balsam Derived from Latin America, this balsam contains volatile (essential) oils which can have @ solvent effect. The balsam has a wonderful red-brown colour and dries to form a glossy finish. However, the essential oils remain active in the varnish/paint film and can cause previous layers to dissolve or pick-up when brushing. Similarly, top coats will be affected by the undercoat. As a consequence, itis used with some caution. When added sparingly to oil or alcohol varnishes it can impart a degree of flexibility due to its elastic nature. Canada balsam Found in Europe from the 18th century onwards, canada balsam is found in a species of pine tree native to northeastern North America. The bark of the tree yields « very pale balsam, not unlike strasbourg turpentine but slightly paler. The balsam only occurs where the bark has Dlistered: as a consequence, collection of the material is protracted and difficult, lending this material @ high price in the market It is used in a similar way 10 venice and strasbourg ‘turpentine. 38Insect Resins i Sticklac-Seedlac-Shellac In Indian, a type of insect, Tacchardia lacea produces sticklac, seedlac and finally shellac. Initially, the insect gorges on the plant juices of various species of acacia tree. The insects secrete @ resinous exudation onto the plant branches, which gradually hardens into a solid mass. In this raw form, itis collected and known as Sticklac, In this form, a red-coloured dye may be oblained by dissolving the resin into alcohol. Once strained, this red coloured “varnish” can be applied as a transparent film, perhaps over ofl varnish to warm the colour up, or simply as a stain in its own right. Although sticklac still contains some impurities, it gives e stronger colour than seedlac and shellac. When the sticklac is pulverised and washed free of impurities, it is then dried and sorted., ‘The largest remaining particles are the most highly prized and are known as Seedlac, resembling the size of seed-pods. It dissolves in alcohol but also spike lavender ofl and lavender oil. Seedlac gives a red coloured varnish which is similar to sticKlac but freer from ‘impurities. During further processing, the seedlac yields a yellow dye and also a portion of wax. When ‘these impurities are removed, the resultant material is known as Shellac. The best quality seedlac is heated then applied to metal sheets and left to cool, before being fractured into ‘small flakes, These thin flakes dissolve readily into alcohol to make spirit varnish. Shellac is, available in a number of colours, the exact shade governed by the amount of wax left in the i seedlac. In some cases, shellac is produced by co-melting the seedlac with other resins such as dragon's blood, gamboge, or softer resins may be fused with (e.g, sandarac), to give more flexible varnish coatings. When preparing shellac into varnish, any waxy residue can be As. filtered out after a few days, as itiends to settle out at the bottom of the container. When bleached or de-waxed shellac is used, it may be very advantageous to include a softer resin when making the varnish, to achieve a coating which will not become brittle or fracture. In summary, it may be more useful for violin-varnishing to use sticKlac or secdlac to gain strongly coloured varnish and to use de-waxed/bleached shellacs, where a glossy, fine and pale coating is required. Propolis (Bee Glue) If the exterior part of the violin is varnished with relatively hard resin types, it can be advantageous to treat the intemal areas with softer resins such as mastic or sandarac. Perhaps the softest of all varnishes for this puzpose can be obtained from propolis, bee-glue. I used in combination with other varnish layers, propolis is far to0 soft to be useful. However, when used alone, as a simple varnish for the intemal parts, it remains soft and pliable (moving ‘with any change sin the wood) and may assist the sound of the instrument. Propolis is found in the hives of bees, forming a kind of crust under the wax and honey. Beekeepers would normally scrape this hard residue off their frames and discard it It contains an interesting coagulation of wax and a proportion of balsam and resinous material (transferred from the plants and trees that the bees interact with). Propolis can be dissolved into alcohol but also spike lavender oil and lavender oil, During the solving process, the wax is removed by allowing the mixture to steep for perhaps a week. At this point, the wax and resin/balsam separate out. The mixture is then cooled to the point that the wax solidifies but the remainder stays liquid and is poured off Solvents As already mentioned, some of the essential oils (e.g. spike lavender oil) have solvent properties. In some respects it is better use these materials to dissolve resins because they impart the properties of slow drying, even-evaporation into the varnish film, which may be desirable. The use of solvents, of which turpentine is a good example, allows for faster solving of resins but also quicker evaporation of solvent from the varnish film.‘Turpentine Classed as volatile oil (subject to change upon exposure to heat and ait), turpentine is distilled form the sap of pine trees. In Europe, production has been centred in Portugal but also other southern European countries such as Turkey. Turpentine is also produced in North ‘America and many other parts of the world. Turpentine is distilled from the liquid mass of pine resin into two portions: oil of turpentine (the liquid part) and colophony resin/ rosin (the solid pari). Distillation varies from source to source: the best qualities are turpentines which have been double distilled, or double rectified. This process filters out a portion of the turpentine which is prone fo thickening upon exposure to heat and air. Turpentine has an ability to reconvert back to @ sappy, thick resinous consistency when exposed fo sunlight and ly on contact with air. As a consequence, turpentine should be kept in a brown bottle (or a closed metal tin), with air excluded. The traditional method is to drop glass marbles, into the bottie to exclude air, after each use of the bottle. In this way, no air or very little air is allowed back into the turpentine bottle. In practice, it is best to use fresh turpentine into varnishes. Ifthe turpentine has thickened, it will impart a soft, sticky residue into the varnish film. This may not be apparent at first, but could leave the varnish film permanently sticky and tacky. Inferior qualities of turpentine may include this sticky residue from the start, or may quickly thicken up. Good turpentine evaporates slowly and evenly from the paint film. Alcohol Old recipes mention using spirits of wine. Some small-scale farmers (in Iialy, contadint) still produce such forms of alcohol, probably in a close manner fo those mentioned in old texts. This more or less pure form of alcohol is excellent for wetting pigments and also for solving resins, In practical terms, unless one is involved with the production of moonshine, procure inslead Water-free Alcohol. This form of industrial methylated spirits is clear and free of the purple or pink colour included in household methylated spirits. The water-free variety is ‘because it is free of any dry residue that may be found in the household type. ‘Alcohol evaporates quickly from the paint film, leaving no residue. Alcohol can also be admixed with water in some instances: for example when using spirit aniline dyes. ‘As stated elsewhere in the text, in some circumstances, alcohol based varnishes can be blended into oil varnishes by the inclusion of spike lavender oil or lavender oil.Ground Layers The varnishing procedure can be said to be reliant upon the laying down of a suitable ground coat, prior to application of varnish layers. There are innumerable theories as to the enact relationship between the ground coating and Varnish layers. In simple terms, it is necessary to seal and equalise the surface of the raw wood, so that the varnish lies on relatively flat surface and does not sink into the wood unduly. ‘Two possible solutions to this dilemma: 1. Glue ground 2 | Mineral ground Glue Ground A simple layer of animal skin glue (e.g. rabbit glue) is applied to the raw wood. A typical glue recipe is: Rabbit glue, in grains 1 part Cold water 15 parts The glue is allowed to soak in water for 1-2 hours, then gently warmed in a bain marie, to for a clear solution. The glue is applied while just warm (never hot), so as not to impart tension into the wood structure. Into the glue solution, « 10-20% volume of nataral powdered mica is added. This mica (potassium aluminium silicate) levels out in the pores of the wood surface and creates a very slight glinting/shimmering effect. Over this dried glue layer (or layers), a thin film of violin rosin can be applied as a ground coat, before further coats of varnish are applied. Minenl Ground © prewar ds Magsler Ee Potassium silicate (waterglass) is also available as a watery suspension, which can also be used to prepare the raw wood, prior to varnishing. A 50% dilute mixture of waterglass is ‘brushed onto the surface of the raw wood, then rubbed into the surface with a clean cotton loth. While this watergless layer is still wet, a Jess dilute solution of waterglass is applied to the surface. When dry, this surface is lightly abraded before varnish layers are applied. The dried waterglass gives a very hard surface, although if itis applied too thickly it may become ‘brittle. A variation of this ground has been formulated by David Rubio and is called Rubio ‘Mineral Ground. This special preparation contains a mixture of materials which approximate ‘o those materials often found in old violin varnish grounds. This special preparation is mixed with tap water and applied into the first (still wet) application of dilute waterglass. When dried completely, a further, Jess dilute coat of waterglass is applied over the top, then abraded to form a smooth surface when dry. When violin rosin is applied over this structure, it leaves the ground transparent. The hard coating of waterglass/mineral ground, acts 2s @ sealing coat, but may also help improve the sound of the instrument. Further information on Rubio Mineral Ground: www.rubioviolins.com www kremer-pigmente-com ‘The Coloured Layers Pigments (and sometimes dyes) are often used to colour varnishes. In general, the desired colour is a warm orange-red colour, achieved by mixing colours together, or by use of @ single colour. While dyes can be said to dissolve into liquids or solvents to form transparent films, pigments retain their particle structure and this structure is sometimes observed within the paint/ varnish film. The particle size and structure of pigments can vary enormously. For example, natural earth pigments tend to have large, irregular sized particles, while modern synthetic organic pigments tend to have an extremely small particie size, which may have a relatively regular shape, from one particle to another. When pigment particles are milled into binder, the liquid binder is required to coat the entire surface of the pigment particle, to obtain optimum working properties.. For pigments with large, irregular particles, this meansthat more binder is required, as more binder is neetied to completely coat the particles (often referred to as “oilabsorption rate”). As a'consequence, the correct proportion of binder to pigments only found through trial and error and experience. Pigments which show transparency tend to be those which have irregular/jagged particles, such as the natural earth pigments. Lake pigments (eg. madder lake) also show ‘transparency when the natural dyestuff has been fixed onto a translucent material (e.g. rock alum). Transparency /transiucency shows in the paint/vamish film in terms of light refraction. Light rays pass through the transparent varnish film and light also bounces off the jagged/irregular angles of the pigment particles, to give increased light refraction. Where light can pass through the varnish layer, it will hit the ground coat and either absorb (dulling effect) or refract, according to the preparation of the ground coat. For example, where potassium silicate (mica) has been applied in the ground layer, this quartz material helps bounce light back and give good refraction, showing as e luminous effect. Pigments which give opaque paint/Varnish films tend to have a regular, usually spherical shape, where light is absorbed into the paint/ varnish film (e.g. synthetic iron oxides). Some plant pigments tend towards opacity because they have been struck (fixed) onto milky, ‘opaque substrates such as fine marble dust or chalk. Historic Examples: Pigments, and Dyes in use 1600-1800 ‘The range of colours available to violin makers during the period 1600-1800 is rather limited when compared to the extensive numbers of colours available at present In a sense, this makes the task of colour matching slightly easier: we have fewer colours to experiment with and less chance of being led away from discovery. However, one must always bear in mind ‘hat the processing of colours during the period discussed, varies greatly to the methods which may be used today. This is particularly true of colours based on plant sources. Industrial methods for processing plant based colours reached a peak during the middle of the nineteenth century in France, with regard to the production of red madder dye for the use in the textiles trade. Prior to this, the processing of plant stuff such as madder into Pigment form was @ small concern, involving insignificant numbers of people. Often the Colours expressed from such plant sources would differ slightly from batch to batch. As « ‘consequence, it is today virtually impossible to colour match dyes and pigments expressed from plant sources to historical examples. Included in this text are various recipes for colour making from plant sources. In all cases, the reader should remember that these recipes are given as examples and cannot guarantee an exact result. Much is also made in various historical texts (see Bibliography) of the use of colour in specific varnish types. Some colouring agents produce wildly different effects, depending on the type of varnish used. The choice of varnish (or binder) can become a crucial aspect. Included in the text are some basic “overview” comments relating to binding agents, resins and vamishes. It would be wise to consider the relative merits of each binder, before beginning to work with colours. A Note Regarding Health & Safety ‘As will guickly become apparent to all violin-makers, the raw materials mentioned in this text can be represented as being potentially harmful if used inappropriately. Alongside the general advice as follows, makers should be aware of the nature and properties of all the Shaterials being handled. This s especially important where the extraction of dyes/ pigments from plant sources are concerned. Certain mordants and other materials useful in these Ensure that you know how to actin case of spillage, etc. The best policy in regard to such ‘materials is to ask the supplier to recommend applicable safety /protective equipment, prior {o use. The advice given in this text cannot be held responsible with regard to interpretation by the end user. 8