Making your own paints - Oil Colours
Sometimes, you need to get have a special paint.
SAFETY FIRST.
Many pigments are toxic to some degree - either in low doses over a long time or in higher doses in a single instance (cronic and acute poisoning respectively) - so, it is important for your own safety and that of those around you to adopt certain practices that will preclude such events.
To contaminate yourself with pigments (or other painting-related compounds), there are a number of routes into your body. The most obvious of these is your mouth. Others include your lungs, skin, nose, eyes and so on. Avoiding activities that allow things to come into contact with these routes is the most effective way of avoiding contamination. So, when painting or preparing pigments, paint, solvent:
- Do not smoke. Apart from the obvious fire hazard with organic solvents, you will be putting things in your mouth that you have handled with your fingers;
- Do not eat or drink for the same reasons;
- Keep your painting related activities in an area that is away from your normal living area (you will be less vigilant when not painting so more likely to become contaminated);
- Keep away from pets, partners and children, whether the materials are in current use or not;
- Pigments are powders that you can breathe in so keep the dust level down by prevention - when mixing pigments, do things slowly and using as little force as possible thereby reducing the energy that can throw powder into the air.
- Do not paint when intoxicated - you will not be as aware of the potential dangers;
- Wear protective clothing so that your everyday clothes do not become contaminated - an apron will do, just something that is going to stop whatever it is that you are working with coming into contact with you or your clothes;
- If you become aware that you might be breathing in more solvent than is healthy, increase the level of ventilation (if you are gilding, don't do it where there are solvents anyway as you cannot have drafts with such an activity.
- Finally, clean up after you have finished. You don't want pigments mixing together but more importantly, you don't want to pick up any contamination from stuff that has not been cleaned away which you can then ingest by accident.
The above is not an exhaistive list. Feel free to be even safer in areas that are not mentioned above as well as those that are.
Oil paints
In oils, the medium is usually linseed oil - it has enough of the oil that oxidises in air and cross-links to go solid yet flexible. There are other oils that contain the glycerol esters of those fatty acids but no in as high a concentration so they tend not to be as strong. In fact, the first oil paint was in Afghanistan and the medium in that was poppy oil.
In the fifteenth century, the renaissance started in the north of Europe and the likes of Memling, Van Eyck, Van Der Weyden, got to experiment with the medium - the result of which was that the colours in the paintings were far more saturated than they were in the preferred medium of the time which was egg yolk.
Another advantage was that the paint took several days to dry whereas egg yolk took only minutes and this led to a whole new way of painting. Instead of having to have a set of mixtures of intermediate tints and shades, colour could be mixed in situ. This, in turn, led to a blending of colours that had never been seen before.
Another thing that they did - and this is backed up by research done by the National Gallery (London UK) is that they heat-treated the linseed oil. This meant that the oil took less time for the cross-linking/polymerisation reaction to take place, therefore the painting dried quicker - something like a few days instead of a week or two. This meant that the 'fat over lean' principle - where you put layers of paint only with increasing proportions of oil in them over the previous layers - was an irrelevance.
'Fat over lean' is a principle that you use when you paint in layers where the layers below have not been given enough time to dry properly. Generally, the higher the proportion of oil in a paint, the longer it takes to dry. If you put new paint over a layer that has not dried all of the way through, there is a risk that the new layer will dry before the layer below - especially as it has more access to atmospheric oxygen than the layer below. If that happens, the layer below will continue to dry out but as it does so, it will split the dried out layer above as it shrinks thus producing a craqueleur effect. This can take anything from a few minutes to several weeks to happen and it is different to the craqueleur that you see in old paintings which is down to ageing and not differential drying rates.
Instead, a layer of paint was applied to the painting and then it was allowed to dry all of the way through. As that layer was completely dried, there was no need to have to make a fatter layer to paint on the top of it. If you have a look at the collections of the Van Eyck, Van Der Weyden et al paintings in the National Gallery or whatever is convenient for where you are located, you will see that the paint, heat-bodied linseed oil and all, has survived a good 600 years or so.
This all happened before Leonardo Da Vinci - the person usually credited with inventing oil paints - had even been born.
So, what does an oil paint need to do before you stick a brush in it?
First of all, it has to set so linseed oil is the obvious choice here because of its strength and the fact that it doesn't yellow that much over six centuries. Avoid adding catalysts that change the rate of setting of the oil - these are called 'sicatives' - as they mess around with the oil itself and that can lead to the production of something called 'soaps' which, in the virtually 'geological' timescale of paintings migrate through the oil layers and form 'pustules' that erupt onto the surface of the paintings like little volcanoes. Also, avoid oil that has been treated with alkali as alkali (as does acid) starts of the saponification process.
Of course, an oil paint has to be usable as you squeeze it from the tube - you don't want it all settled to the bottom of the tube whilst you have had it in your drawer or box or standing up in a mug or whatever so if the density of the pigment is not too different to that of the oil, it is fairly likely to stay as a homogeneous mixture. However, if it is substantially heavier, it will settle and form a fairly solid lump. With water colours, you have the advantage of the stored paint being in solid blocks but that isn't practical with oils. So, we can't do anything about the density of the oil but we can make it more viscous. Traditionally, this is done by adding beeswax to the linseed oil but pigments vary and some need to have more wax added that others. So, we need to be able to do something about that.
One thing we can do during the making of the paint is make it less viscous whilst we work on it and we can do this by adding some English double distilled turpentine which can evaporate off at the end. You won't need much and it can help.
So, first thing to do is select your pigment which should be dry and not have any unwanted bits in it.
Unless it is an expensive pigment of which you are only going to make a small bit of to use immediately, you should aim at making a tube's worth or thereabouts - better to be a bit under rather than a bit over so in the middle of a grinding slab that is hard enough for your pigment.
Here, we have some verdigris that I have made myself and it has a hardness of 1.5 so marble with a hardness of 3-5 is a safe choice.
Make a pile of pigment in the middle, keeping the spill away from the edges of the slab. Remember that it is a powder so whilst it is dry, it will be very fluid and therefore you have powder handling problems related to the toxicity of the pigment you are using.
In the middle, make a depression and then put in there some linseed oil of your choice.
If you are making paint for a tube and your pigment is particularly dense, say it is a compound of mercury, lead, cadmium, chromium and so on, you are going to need to adopt strategies that reduce or prevent settling out of the pigment during storage.
One strategy is to not add very much oil and this is something that you should be aiming for anyway. The other is to add something that modifies the viscosity of the paint.
A traditional substance that is added is beeswax.
On the right is a small pot of white beeswax that has been dissolved in double distilled English turpentine. Simply adding solid beeswax to the pigment or pigment-oil mixture would not work because it is simply too hard. Instead, this is one part by volume beeswax to roughly four or five parts double distilled English turpentine.
It was made by putting the beeswax in the jar then filling it up (not all of the way leave around a fifth of it empty) with turpentine. Then, heating it in hot water from an electric kettle (not boiling or you might crack the glass of the jar) that has been poured into a saucepan. By leaving an amount of air - 10-20% - it is possible to shake up the contents of the jar. Let the jar warm through and the beeswax will start to melt and dissolve. Finally, let the wax-turpentine mixture set and it can be stored in the usual conditions for months to years.
Use a palette knife to take a small quantity of of the wax-turpentine mixture which is soft enough to add to the pigment-medium mixture without causing lumps of wax to remain in the paint. The amount you need to be looking at is to make a linseed oil to beeswax mixture of about 9:1. Remember that the wax-turpentine mixture is only a fifth beeswax.
This should mix in really easily because the beeswax has turpentine in it which will loosen up the linseed oil quite a bit. Mix it in well with the palette knife and the turpentine should evaporate out of it - a step that should be fairly complete before you start grinding the paint.
Hopefully, you should end up with a mixture that is like a hard paste - there is so little oil in it that the grains of pigment are held together by a mixture of atmospheric pressure and surface tension - not the wax.
The pigment grains are not little spheres, they are randomly sized and shaped and the sharper bits fit in between the gaps between adjacent grains so that it all fits together rather well - if you put the palette knife in the paint and vibrate it, it will flow yet if you apply a steady force to it, it will tend not to. Clearly, you cannot paint with this so we need to grind this using the muller on the slab. This is identical in operation to grinding water colours and if you feel the need to add any solvent, you can add turpentine instead of water.
Pile up the pigment in one corner of the slab and slice off small amounts of it at a time and grind it with the muller. You will find that the paint 'block' will lose its rigidity and if you have the quantity of oil right, it will become like the paint you get out of the commercial tubes of oil paint except that you know what is in this paint.
As you work you way through the paint, pile up the ground paint and when you have finished, mix it all together with the palette knife to make sure that it is the same all of the way through and that it is the correct consistency.
Once you are happy with it, use the palette knife to put it a bit at a time into a paint tube. Every now an then, hold the tube vertically and tap it gently against the work surface so that the paint goes to the end with the lid and any air that is entrained in the paint works its way to the open end.
When you have finished, the surface of the paint should be a minimum of 1.5 to 2 tube diameters below the rim of the tube.
Between your thumb and forefinger, carefully press the end of the tube flat and try to squeeze out any air that might be left in the tube.
Next, fold over around 5mm of the end of the tube then do so again and again, and when you are satisfied that the end is folded over enough, use a pair of pliers to crimp it flat - being careful not to make a hole in the metal tube with the end of the pliers.
Then, write a label for it with at least the name of the colour on it but you might with to add the date it was made, where the pigment came from, what is in the paint, and so on.
Finally, squeeze a little from the tube onto your finger (you might want to wear a glove or you might not) and smear that paint over the edge of the label like has been done in the photograph, then let it dry. (This is a photograph almost two years after it was made.)
Even though I had heard of this from the literature, it still came as a bit of a surprise to see it for myself and, with something that I had made myself.
The green smear is from the 24th April 2017, from the freshly prepared paint.
I looked at it and couldn't believe my eyes so I made another smear next to it.
Just to make sure and also get a time scale on this, I repeated it a couple of days later.
you can see that the smears from two and four days are essentially the same hue so this takes only a couple of days to happen.
This is not a peculiarity of making your own paint, it is a peculiarity of verdigris paint and is well documented in the literature.
Here is the paint nearly two years later - still comes out of the tube in a smooth, cylindrical shape without using much pressure.
Works just the same as two years earlier.
Perfect.
Meet the family. You can't get these easily anywhere and you certainly can't get them for the same price. I know what is in these paints because I put it there myself. No secret ingredients, no bulking out pigments or using 'alternatives' - these are all the real thing.
From left to right:
Vermilion; Chrome Yellow; Lead-Tin yellow II; Lead-Tin Yellow I; Home-made Dutch Stack Lead White; Malachite; Home-made Verdigris; and, Smalt.
All images and original artwork Copyright ©2019 Paul Alan Grosse.
