A medium is a substance added to paint in order to alter the way the colour appears and behaves. There are a number of reasons why you might use a medium, including to alter sheen, drying time, texture or transparency. Mediums are available to suit oil, acrylic and watercolour, although they are not compatible across media. Here is a summary of all the different varieties of medium available by media.
Alkyd is a synthetic resin that has come into popular use in colours and mediums within oil painting. The Winsor and Newton Griffin range of colours uses Alkyd resin as its binder. The advantages in doing so lie in the speed at which alkyd resin dries, and also its low cost. Unfortunately alkyd resin does not have the same colour holding capacities as a natural gum resin such as damar might have, which is used by Schmincke in their Mussini oil colour range. This means that the colour depth and brilliance is compromised slightly. However alkyd mediums are perfect for students or beginners, as well as for using when painting out of doors for all levels of ability (ease of use, practical reasons). It is also a good medium to use in the initial layers of a painting (underpainting) as it dries quickly, and one can then continue to work over the top with a medium that is made up of more lustrous, richer ingredients, if one so desires. Remember always the fat over lean rule – this means that the initial layers of oil colour should have less oil content than the layers applied over the top in order to allow the painting to dry solidly throughout the layers – this will give your painting stability and minimise the paint’s ability to absorb water from the air. Alkyd is also used in C. Roberson’s Oil Primers and Jackson’s Thixotropic Alkyd Oil Primer, and this allows these primers do dry a lot faster and be sold at a much lower price than the pure lead primer by Jackson’s. There are many alkyd mediums available, with varying consistencies and by a number of brands – check the details of each individual product for their unique characteristics. Brands Available Include: Jackson’s Fast Drying Oil Painting Medium, Jackson's Alkyd Oil Medium and Jackson's Gloss Gel Medium for Oils Winsor and Newton Liquin (all varieties) Daler Rowney Alkyd Flow Medium
There are a number of pre mixed mediums that use traditional, natural ingredients that achieve a greater degree of colour brilliance and depth. Because these mediums replicate the recipes used by painters for hundreds of years, we know the extent of their permanence and stability. If you know you are only going to use a specific ingredient for one purpose, i.e. as part of a particular medium, then buying a pre mixed medium might be the most cost and time effective way of doing so. If you are more likely to want to explore the possibilities with how to alter and manipulate mediums by altering the ingredients and their proportions, then it may be better to buy the ingredients separately to mix yourself.
Some of the Pre-mixed, traditional mediums available:
Below is a brief guide to other ingredients that you might mix with oil to make your own oil painting mediums based on traditional recipes.
The rectifying process is carried out by steaming out the spirits of the turpentine. This is different process to distillation of the spirits, yet serves the same purpose of removing any impurities that may have a disadvantageous effect on its drying process. Rectification is a mechanical process that uses water and is a much newer process of purification than distillation.
Beeswax is a popular medium among artists who like to paint more gesturally or with impasto colour. It is a mixture of linseed stand oil and bleached beeswax paste. It thickens oil colour and dries with a semi-matte sheen. Beeswax is particularly effective when mixed with semi-opaque and opaque colours.
Solvents can be divided into two main categories: Those that are extracted from pine trees and those which are petroleum based. Generally it is considered that the solvents that are extracted from pine trees are better suited to using in painting mediums, and in the cleaning of brushes etc., but the quality of these gum-resin based solvents (turpentine) vary hugely, so it is worth considering this when making your decision on which to buy. The quality of these is reflected in the price you pay. Many manufacturers call their high quality turpentine different names, and so if one comes across an English distilled turpentine, or a rectified turpentine, or a gum spirits of turpentine, one is going to be looking at pretty much the same product, and it would all come down to testing each one out to see which one does the job best for you.
Pure turpentine contains more impurities than English Distilled turpentine but is great as a brush cleaner prior to rinsing with soap and lukewarm water. Turpentine is made from the gum resin of pine trees, which is then purified or distilled or rectified to remove the impurities found in the resin, leaving a pleasant, pine smelling, yet effective thinner and cleaner of oil paint. If your turpentine does not smell as good, it could be down to the fact that it may have not been purified to the same extent, or that it may have been made from the mulch and dead pine tree leaves and branches as opposed to a live tree source. Such turpentines will be less stable and although may be cost effective, we would only really recommend these for cleaning brushes and not as an ingredient within an oil paint medium. We strongly recommend using all qualities of varieties of turpentine in a well-ventilated work area, as inhalation of the fumes should be kept to a minimum.
Warning - turpentine may suffer some discolouration if exposed to air over a prolonged period of time, so always worth keeping the lid on tight when not in use.
White Spirit is a paraffin derived, clear transparent liquid, and generally speaking is considered too unstable to be used in oil paint mediums, although can be used as a very effective cleaner for brushes after an oil painting session. However there are special ‘Artist’s White Spirit’ such as the one available from Winsor and Newton, that Winsor and Newton claim is suitable for painting with as part of a medium.
Low odour solvent is another petroleum based thinner, which has had its harmful aromatic solvents removed from its hydrocarbons – while Jackson’s calls theirs a ‘Low Odour Solvent’, Winsor and Newton call theirs ‘Sansodor’ (a name derived from the French for ‘without odour’) and it is worth remembering that these are much the same product. The key things to remember with these are that they are less stable than the very finest turpentines, they dry slower when mixed as part of an oil painting medium, and even if they do not emit as strong an aroma into the atmosphere, they still contain harmful fumes that should not be inhaled and so a well-ventilated studio is of paramount importance to the healthy artist’s well-being!
If the artist is concerned about one’s well-being in the studio and would like to find a friendlier solvent to use, then Zest It is our recommendation. Zest It is a solvent, primarily for use by oil painters. It is made from an Aliphatic Hydrocarbon and pure food grade Citrus Oil. It has a neutral pH value and contains no CFC's or Aromatics and has low VOC's. It is a clear, colourless liquid which has a pleasant 'citrus' smell, is inherently biodegradable and evaporates without leaving any residue. Independent laboratory tests show it has no detrimental effect to the oil paint or pigment quality, proven stability and a long active life. It does not emit any harmful paint fumes and although it is a little more expensive than other solvents, it can be recycled (left to stand so residue sinks to the bottom, and the clear Zest it can be decanted into another vessel to be used again). If you are looking for a solvent with a longer history of use, then Oil of Spike Lavender smells of fresh spring meadows, and has been used by oil painters for hundreds of years. It does emit some fumes but not as many as turpentine, low odour solvent or white spirit might, and it is less potent, and less abrasive than any of those solvents. It has a thicker consistency, and is known to be great for maintaining the quality of brush hairs when used straight as a brush cleaner at the end of a painting session, as well as part of a lustrous, easy-to-use painting medium when mixed with stand oil. It is pricey but a real treat for any serious oil painter.
Larch Venice Turpentine is not for cleaning brushes – it is a thick, thixotropic natural balsam that is extracted from resin (oleoresin) and mixes beautifully with oils (especially walnut or stand oil) and a little distilled turpentine to make a thick, lustrous, glossy, rich oil painting medium that increases the transparency of your colours.
Pure Turpentine is a natural product distilled from pine trees. It can be used in oil painting mediums by mixing with oil (linseed, linseed stand, walnut or safflower etc.). It is also great for cleaning brushes as it is effective yet is not as strong as white spirit and will not dry out the natural moisture of your brush hairs as much. However please note that prolonged exposure of natural hairs to any solvent will accelerate the deterioration of the quality of the hair and cause them to become brittle and break more easily. Turpentine can also be used to thin oil based varnishes, and is superior to white spirit in its ability to blend easily with oils to create even mixtures. To make your own varnish you can simply suspend damar resin crystals wrapped in a lint free cloth into a jar of pure turpentine until the crystals have dissolved. Turpentine’s slow evaporation rate creates a gradual drying time, which again, allows for a more lustrous finish to dried colour that has been mixed with turps.
Warning - turpentine may suffer some discolouration if exposed to air over a prolonged period of time, so always worth keeping the lid on tight when not in use.
Larch Venice Turpentine is a slow drying thixotropic balsam for use in mediums and varnishes. Pure resin from the Austrian Larch tree purified and slightly heated when decanted. Dilute with turpentine or place in warm water bath to obtain fluid consistency.
A layer of varnish on a finished painting will protect it from dust, dirt, grease and UV rays. It will also even out any unevenness of sheen on a paint surface e.g. a gloss varnish will make the whole picture surface equally glossy. All solvent varnishes are made up of resin and solvent. The resin provides the stable, solid, fast drying and glossy component of the varnish, and the solvent the liquid vehicle, which evaporates in the air with time which allows the resin to solidify once more after the varnish application. There are 2 main types of solvent varnish - a final picture varnish, and retouching varnish. The difference between the two is that the picture varnish will have a greater resin to turpentine ratio than the retouching varnish. The reason why is that the picture varnish is designed to be more concentrated to form a more solid, continuous layer of resin over a finished work, the layer will be even in its appearance. Its strong, solid structure will not allow water or other liquids to permeate through it, and conversely will not allow any liquid still contained within any semi-dry oil colour beneath the layer of varnish to escape into the atmosphere.
If a painting is not sufficiently dry when varnished with a final picture varnish blooming may appear, as well as more visible cracks in the varnish as the paint beneath shifts. This is why it is very important to not apply a final picture varnish until the painting is at least 6 months old. Picture varnishes should be removable so that they can be taken off and replaced with a new layer if the old layer gets damaged or dirty, and all good varnishes will state the best means of removing varnish (although it will be with the use of the solvent that is used in the varnish itself). Because retouching varnish has more solvent in it, when it dries liquids are able to permeate through the layer of varnish, which means that the painting does not need to be fully dry before its application. It is used as a temporary protection layer as well as a device to unify sheen during the painting process.
Small quantities of varnish are also sometimes used in oil painting mediums to act as a siccative (to speed drying) as well as add a little more gloss to the finish. The resins used vary but typically it is damar resin if it is not a synthetic alternative, such as ketone. Damar resin is extracted from the Dipterocarpaceae family of trees in India and East Asia, and as well as in varnishes, can also be found in the binding of Schmincke Mussini oil colours. It is thought to increase the appearance of colour brilliance, and is a good ingredient in oil painting mediums as it has a good colour holding capacity.
Generally speaking, damar is preferred to synthetic resin as it is thought to provide a deeper, more lustrous finish, as well as being less likely to yellow with time and having more stability. The solvents are either turpentine or white spirit, which dries slightly slower than turpentine. Winsor and Newton also offer a range of Artisan varnishes which are water-based and to be used to protect fully dried paintings created with the use of Artisan colours, and can only be removed with the special Artisan varnish remover. All solvent varnishes can be applied with a spray or a thin flat varnish brush, and can be used on all dry oil, alkyd or acrylic works.
Matt varnishes can be made 2 ways – either with the use of a wax that is matt anyway when dry, or by adding a matting agent to a varnish that would otherwise dry gloss. Michael Harding’s matt varnish is made with beeswax and double rectified turpentine and C. Roberson & Co also produce a similar beeswax picture varnish. C. Roberson and Co.’s ‘Matt Varnish’ contains a petroleum based microcrystalline wax, which is elastic and adhesive in its nature, as well as matt in appearance. Matt varnishes by Royal Talens and Jackson’s Art Supplies contain a matting agent (in the case of Royal Talens they use silica), which serves its purpose but the only snag is that the matting agent tends to be marginally denser than the other ingredients in the varnish and will sink to the bottom of the bottle over time. This may lead to an uneven sheen, so it is absolutely vital to give your bottle of matt varnish a thorough stir or shake prior to use.
It is both cheap and easy to make dammar varnish, to use either as a retouching varnish or a final picture varnish. It is a case of diluting one part dammar crystals to one part turpentine. Wrap your crystals in a piece of cheesecloth or muslin and tie at one end, and suspend in a jar of your solvent. As I said earlier, the more refined the solvent the easier to use the varnish, so try and use something that has been rectified or distilled of its impurities. You will need to gently stir every now and then for the following 2-3 days, as the crystals break down. After about 3 days all the crystals should have dissolved and you then have your damar concentrate. With this you can either a) make picture varnish, by mixing 1 part damar concentrate to one part solvent, or b) make retouching varnish by mixing one part damar concentrate to 3 parts turpentine. You may also make a matt varnish by also diluting a quantity of beeswax in the same jar of damar concentrate.
Those who favour working in acrylics are often attracted by the myriad ways the paint can be manipulated with the use of mediums. Acrylic mediums and gels are made using the same acrylic resin binders that manufacturers use in making paint, to which various other materials including marble dust, stone and mica are added in order to alter the consistency and behaviour of the medium which in turn will manipulate the paint when the medium is mixed with it. Jackson’s Artist Acrylic range includes a number of gels and mediums which are described below, and we also sell acrylic mediums by Golden, Liquitex, AV, Daler Rowney, Winsor & Newton, Lascaux and Ara.
Acrylic gel medium is available in Daler Rowney (known as ‘Impasto Gel Medium’), Jackson’s, Golden (known as ‘Heavy Gel’ and is available gloss, matt or semi-gloss), and AV. Jackson’s Acrylic Gel Medium is made from acrylic polymer emulsion, and is of a heavier viscosity that the Jackson’s Artist Acrylic. By adding this medium to your colour you will extend the colour, increase its transparency, and slow the drying time a little. Gel medium is particularly good for heavy impasto techniques. Golden also do a ‘Regular Gel’ in gloss, matte or semi-gloss, and this is of a similar consistency to Golden Heavy Body Acrylic but still may be thicker than some other acrylic colour ranges. (Please note that brands can be mixed).
These mediums will thin heavy body acrylic colour, but are usually of a similar consistency to fluid colour. They extend the colour and increase the transparency. It is worth checking each individual brand with regard to how they affect the drying time – AV’s does not alter the drying time because it is made using the same acrylic emulsion as the paint itself. Jackson’s and Golden also do their own versions of this product.
Jackson’s, AV and Golden all offer retarders as part of their acrylic medium ranges. These slow the drying time right down, and also extend the colour and increase its transparency. It is advised not to mix more retarder than 10% of the colour you are mixing with as this will weaken the bonds between the acrylic polymer particles in the paint too much and cause instability in the dry acrylic paint film.
There are so many other mediums and gels to explore, so if you are interested in really making unique paintings then it is worth having a look. There are mediums to make paint appeared cracked and aged, mediums to make paint stringy, sandy, gritty, pearlescent, pasty…there are gels to alter consistency, reduce brush marks, increase brush marks, increase gloss and decrease gloss. Experiment where you can, you might even want to mix mediums and see what other possibilities there are.
Gum Arabic is used to bind pigment in watercolour manufacturing processes, as is made of hardened sap extracted from 2 species of the Acacia tree. It is sometimes known as chaar gund, char goond or meska. Gum Arabic dissolves very easily in water, and is used as the binder in watercolour because it also effectively binds the pigment to the paper surface once the water has evaporated. Gum Arabic allows for more precise control over watercolour washes as it limits the amount of flow and/or bleed of the colour. Gum Arabic also allows the evaporation rate of water, which means that it keeps your watercolour wet for longer, allowing for longer working times. Once water has evaporated from watercolour, the colour’s luminosity and transparency, as well as permanence, is enhanced by the gum Arabic. Gum Arabic is sold separately for those who wish to try making their own watercolour paints by combining it with dry pigment, and it can also be used as a medium to mix in with pre-made colour, to further optimise transparency, luminosity and lightfastness.
As well as in watercolour, gum Arabic is sometimes used in lithography, and can also be used to transfer images from photocopies, photos or magazines (you can also transfer images using acrylic mediums). Simply sponge the gum Arabic on to the image, and then roll oil based ink over the photocopy. Ink can then be easily removed from the white areas by carefully wiping with a damp sponge.
Jackson’s Art Supplies sells gum Arabic as manufactured by Schmincke, Jackson's, Daler Rowney and Winsor and Newton.
When granulation medium is mixed with watercolour paint it gives it a mottled appearance when the colour would normally appear as a smooth wash. Some colours naturally do have a mottled or granulated appearance, such as French Ultramarine. Granulation medium would serve the purpose of increasing this characteristic in such pigments.
Schmincke Aqua gloss remains watersoluble, and can be applied on to dry watercolour to enhance its gloss, or mixed in with wet watercolour as a medium. It also slows the drying time. It is advised not to mix aqua gloss in a watercolour pan as it may affect the paint for future use.
Aqua Shine and Iridescent medium are both pearlescent watercolour mediums that add a shimmer effect to your colours. They can also be applied to work pure. Both Aqua Shine and Iridescent Medium retard drying and stay watersoluble.
Ox Gall for watercolour is made of the gall from cows mixed with alcohol. It is a natural wetting agent for the degreasing of undercoats – i.e. it allows for greater adhesion on to already dried layers of watercolour paint. Ox Gall can also be used in gouache painting. Used sparingly, ox gall can also be used as a watercolour levelling agent.
Winsor and Newton Blending Medium slows the drying time of watercolours which enables a longer amount of time for blending. Winsor and Newton Blending Medium is therefore particularly useful when painting in a hot climate.
Schmincke Aqua Collage is formulated for artists who wish to use watercolour in mixed media works. Aqua Collage dries water-resistant. It is an adhesive that can be applied on its own (in which case it will dry clear and invisible) , or it can be tinted with watercolour. You may wish to use it to glue photos or coloured paper to your watercolour paper, and then work over the top once dry. When dry aqua collage can be painted over without resisting the paint in the way that PVA glue might.
Schmincke’s Aqua Effect Spray is for the very experimental watercolour painter! Spray into wet watercolour work to create what Schmincke refer to as ‘bizarre surface effects’ on watercolour paintings – basically, it causes the pigment to gather up into pools, to create something a little like flocculation, but also a little like a marbling effect – the colour gathers in pools of saturated colour and leaves area of transparent thin layers of less saturated colour – the surface is broken and undulates. It is worth trying it out on a separate piece of paper to fully understand what it does and whether it is what you want to use on your work. Because Schmincke Aqua Effect spray is in a pump spray bottle, be sure to mask off any areas that you do not wish to apply the effect to.
Aqua Pasto watercolour medium is manufactured by both Schmincke and Winsor and Newton. I see Aqua Pasto bridging the gap between watercolour painting and the kinds of impasto techniques you’d be more familiar with in oils or acrylics, and it really does open up the possibilities with watercolour. This is a transparent thickening medium which can be applied pure on to paper, or mixed with colour prior to application, and allows a paste-like texture. You can even start to apply your watercolour paint with a spatula! Aqua Pasto reduces flow, and increases gloss. It slows the drying time and stays watersoluble, so can be re-worked over time.
There are a few mediums available for pastel. In addition to these adding a little water as you work can also help achieve more fluid effects.
In the Pan Pastel range there are a number of mediums that come in the same pans as the colours. The mediums available are the colourless blender, pearl white (fine and coarse) and pearl black (fine and coarse).
All mediums are mixable, erasable, low dust, lightfast and of professional artist’s quality.
The colourless blender increases transparency and enhances colour flow.
The other mediums add either a fine or coarse, black or white pearlescent sheen to your colour.
This medium can be applied directly to soft pastels to temporarily liquefy colours. This allows pastel colours to be mixed and blended giving effects not usually associated with traditional pastel techniques.
Please note: This product is not a pastel fixative.
Gum Tragacanth can be used as a binder in the making of soft pastels. Here is a basic step by step instruction of how to make soft pastels at home.
1. In a bowl mix one part gum tragacanth to 20 parts distilled water with a whisk.
2. In a well ventilated room and in another bowl mix the French chalk/whiting with your pigment. The ratio should be no more than 2 parts chalk to one part pigment. The colour of this mix in its dry state is a good indication of the colour of your finished pastel.
3. Add the gum tragacanth and water mix very slowly to the pigment, stirring as you go to form a dough.
4. With rubber gloved hands, you can now roll your mixture into the desired shape and leave to harden.