Acrylics dry very quickly. The drying process consists of various stages, but generally, the paint is sufficiently dry after 10-15 minutes, making wet-on-wet techniques no longer feasible.
Please note: the actual drying time is much longer; a regular layer of acrylic paint will only be completely dry inside and out after one to two weeks. This is particularly important to remember if you plan to varnish your painting after it’s finished.
There are two options: either you can try yo extend the drying time, or you can learn to work with the properties of acrylic paint.
Retarder
Retarder extends the drying time by approximately 20%. You can mix it with your paint.
A 20% longer drying time means that your paint still dries relatively quickly (compared to oil paint). It does provide you with a little bit of extra time to work with it, but don’t expect miracles.
When adding retarder, you should be cautious. Typically, you should not exceed 5% retarder in relation to your paint.
Slow-drying medium
Slow-drying mediums extend the drying time. A big benefit compared with retarder is that it doesn’t matter how much you add to the paint.
However: medium of course makes paint more transparant as well. So, the more you add, the more transparant the paint gets.
Slow drying acrylics
Some brands produce acrylics with a slow drying time. For example: Golden Open.
Sta-Wet Palette
You can buy or make a palette that keeps the paints moist.
It’s a kind of box. At the bottom, there’s a moist sponge. On top of it lies a sheet, the palette. The paint is kept moist from underneath.
After painting, the box can be sealed airtight. This allows you to preserve the paint for a much longer period.
Mist sprayer
One of the best tools in my opinion. Depending on your environment (in a warm and dry environment paints dry quicker) you can spay some mist on your palette. It keeps the paints moist for a very long time.
You can also use it on your canvas. If you want to paint wet-in-wet, just keep the paint on your canvas slightly moist with the sprayer.
Palette Preparation
Make sure you prepare an ample amount of paint on your palette, better to have too much than too little. When there’s more paint on your palette, it dries out more slowly.
Of course we don’t want to waste paint. But in the end: you make more mistakes when the paint dries too quickly, costing you more paint in the end trying to solve the problems.
Pre-mix important colors with a palette knife
If you premix the most important colors that you need in the painting session, you can paint more quickly. The paints are already there on your palette, so you can quickly load your brush and go.
When you mix with a brush, the paint dissapears in the bristles and there’s nothing left on the palette. When you mix with a palette knife, you can make piles of paint. Piles dry out way more slowly.
In the example below, I’ve first premixed the green colors for the blouse. Pre-mixing cost me more time than painting, because painting was just a matter of putting the colors at the right spot.