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Acrylic Paint
Preparation Predispersal requirements etc
Attempting to make Acrylic Paint from base ingredients is difficult but
the following method based on using pre made acrylic mediums is fairly
straightforward. It has the advantage that the same basic technique
can easily be adapted to make a huge range of paint qualities and
characteristics from thin ink-like fluids to thick textural
constructional pastes. Gouaches and Watercolor like paints are easy to
make as well as more conventional thicker Acrylic Paints.
Pigments should be predispersed using distilled water and Surface
Tension Breaker. About 50/50 liquid to pigment will make a suitable
paste. Several pigments will disperse very easy. Ultramarine is
probably the easiest, but some of the synthetic organics such as
Quinacridone will be unco-operative. The easy to disperse pigments are
best dispersed by simpling mixing in a plastic container with a spatula
(see below) but the difficult pigments will be best mulled on the slab.
Golden sell a product called Universal Dispersant that is particularly
good at wetting the pigment and maintaining the long term stability of
the pigment dispersion.
There are some problems to watch out for:
- Foaming. The Acrylic emulsion already contains
surfactants. Like dishwashing detergent they foam easily. Use of
defoaming agents may be necessary.
- Drying. Like when making Watercolor drying can
occur (especially at the edges) during dispersal and needs to be
avoided.
- Overuse of modifiers. Too much defoamer can be
a problem, same with Retarder, take care when measuring.
- Maintaining alkalinity. The pH can easily fall
as ingredients are added and the paint will cease to be viable paint
beyond a certain point. Increase pH with ammonia.
- The hydrophobic nature of pigments. Use wetting
agents or even a little Grain Alcohol to wet the pigments.
You will find a straight sided 1 liter (2 pints) plastic bucket with a
flat bottom the ideal mixing container that is not too big, not too
small. An eyedropper is valuable for adding small amounts of liquids
like ammonia or defoamer. A plastic spray bottle can help keep the
paint wet during mulling.
Related Links:
Ingredients for Acrylic paints
Pigments
Grinding or mixing Also
called dispersal
The proportion of pigment to binder varies according to the pigment
from 40% to 60%. It is possible to add more pigment but beyond a
certain point this will reduce adhesion and durability of resulting
paint films. The trick is in finding that sweet spot that is optimal
for each pigment. In general the percentage of mineral based pigments
like Ultramarine will be higher, while the percentage of organic
pigments will be lower. Manufacturers tend to be secretive
about their exact formulations so a little personal
experimentation is required. The good news is that the latitude is wide
in Acrylics and generally if you are going to have a problem with a
paint the problem will be apparent as soon as the paint dries.
It is at the initial mixing stage that matting agents should be added.
It is advisable to make a couple of small amounts of paint with an easy
to use pigment with varying portions of matting agent in order to
arrive at the portion that suits you. As always when making paint note
everything down as it is easy to forget or get confused about amounts.
Most mineral type pigments disperse easily from the pigment paste into
the chosen Acrylic binder by mixing with the spatula in the bucket.
Start with 50/50 and then add more as the mixing proceeds. At first the
paint will seem to get thicker then after vigorous beating the paint
will become noticeably smoother. It is important to make certain that
there are no areas of the container on the bottom or edges that are not
so well mixed as the rest. Test with a drawdown
Organic pigments may well require mulling. Start in the bucket with a
little less than half pigment to binder then add pigment paste as
necessary. Use drawdowns as necessary to check dispersal. If necessary
pour a little on the slab and mull in a circular motion, scraping the
paint into the center and from the edge of the muller as necessary.
Work quickly but be wary of foaming. Use a spray bottle to keep moist
if needed, but don't over wet. Making Acrylics is often better done at
night as the humidity is higher and drying less an issue. Defoamer
should never be more than 1% of paint volume. Retarder never more than
15%.
It is important to monitor pH as when the pH falls below 8 the paint
can become more like cheese than paint. If this happens just throw it
out, it is ruined. To monitor pH it is possible to use litmus papers I
guess, but the smell test is easier. At the correct pH the paint will
have a distinctive ammonia like smell and will lose it as the pH
lowers. Adding ammonia a few drops at a time will retain the
appropriate alkalinity, ideally between 8 and 9.
Rheology needs to be considered here. Acrylic paint can vary from thick
and honey like, as in automotive paints. This is 'long' rheology. Less
resinous, and less stringy paint has 'short' rheology. This is not the
exact equivalent of the terms long and short in oil paint where the one
kind of buttery quality is sought. In acrylics it may be desirable to
make a variety of rheologies.For example it is possible to have
high viscosity with either short or long rheology and the same for
lower viscosity paints. Each has a role and only artist preference
dictates which is best in any given situation. Fortunately Golden makes
thickeners of both long and short rheology that make this kind of
formulation choice easy.
The degree of fluidity, the level of surface sheen, speed of drying and
so on can all be modified considerably. As this is more to do with
personal taste than practical issues such things should be left to
individual experimentation. Available products can be found here Technical support is often provided by
Acrylic manufacturers.
[ Go to Testing paints ]
Filling tubes and jars Storing
paint
Having made your Acrylic paint the storage method needs to be decided
on. Tubes are popular and easy to use but larger quantities of paint
may require storage in plastic buckets. Putting a sheet of Gladwrap
over the paint surface helps prevent surface drying.
Related Links:
Studio notes
Basic Ingredients
Detailed Ingredients
Testing paint
Starting to make paint
Making Oil Paints
Making
Watercolors and Gouaches
Making Egg Tempera
Making Hide Glue Chalk
Gesso
Making Encaustic
Paint
Making Fresco Colors
Making Pastels
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Frequently Asked Questions
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