Acrylic paints have a tendency to dry darker which can make it difficult to match colors. The color may appear to match when it’s wet, but then it dries darker. This can be frustrating, but with a few tips you will be able to compensate for it intuitively. Matte acrylics can actually dry lighter but since the majority of acrylics dry darker, that’s the focus of this article.
Acrylics dry darker because the acrylic emulsion is cloudy when wet and dries clear. If your color dries darker, the solution is to add a touch of white to the mixture. It will appear to be too light when it’s wet, but it should dry to match the color you wanted. Another option is to switch to Winsor & Newton’s professional line of acrylics because they’re the only acrylics that I’m aware of that uses a clear binder and don’t have this problem.
Acrylic Binder Is Cloudy When Wet and Dries Clear
Acrylic medium is basically acrylic paint without the pigment and it has a cloudy appearance. In the photo below, I poured out a small drop of acrylic pouring medium on a sheet of black foam board to make the milkiness of the acrylic medium more obvious. The wet acrylic medium is on the left. The edges were transparent after 12 hours but the center still had a slightly cloudy appearance. After 24 hours the puddle of acrylic medium was dry and totally transparent. I think regular gloss medium would have dried faster but I used pouring medium because thick puddles of acrylic can crack as they dry. The pouring medium has additives that prevent cracking and crazing.
This photo is also a good example of how long it can take for acrylics to fully cure. The pouring medium was dry to the touch after 12 hours but the cloudiness indicates that there’s still moisture within the acrylic resin. Normally this isn’t visible because the opaque pigment disguises it–you can’t see past the surface of the paint. The cloudiness of the acrylic binder is like adding a temporary white to your paints that disappears as it dries.
Wet to Dry Acrylic Paint Comparisons
In the above photo are of four colors that dry darker to varying degrees: Phthalo Blue, Pyrrole Red, Phthalo Green, and Burnt Sienna. The phthalo colors are very dark when used straight from the tube so I mixed them with white. I made sure that I mixed enough of each color so that I would have the same exact color for the wet and dry comparisons.
The photograph was taken immediately after I added the wet paint. The dry version of the color is at the top and the wet version is at the bottom. The Burnt Sienna and Phthalo Green seem to be affected the most while the Pyrrole Red almost looks the same. I should also mention that the difference was easier to see in person than in the photos
How to Compensate for Acrylics Drying Darker
Not every color will dry darker, with experience you will learn which colors suffer from this effect the most. The way to compensate for this is to match the color as you normally would, and then add a small touch of white to lighten it. As it dries, it should darken to the shade you had intended.
I usually keep a small sheet of scrap paper near my easel to test my color mixes on. It doesn’t have to be fine art paper, but it helps if it’s thick so it doesn’t buckle from the moisture. I also keep a hair dryer next to my easel so I can dry the test samples quicker. It’s not always necessary to go to this level for every color that you mix, as that would be time consuming. For example, I intuitively know that I need to mix sky blue slightly lighter than the shade that I want so I don’t test it on a scrap of paper. Eventually, you’ll develop a feel for how much white to add to compensate.
Titanium white is probably the most common white pigment because it’s so opaque. A very small portion of Titanium White is enough to lighten the color mixture to compensate for the way acrylics darken as they dry.
Another option is to use Zinc White, which is much more transparent. It’s also available as a “Mixing White”. If you find that you’re adding too much Titanium White, then you may want to try Mixing White because it’s more forgiving.
How Will This Affect My Painting?
Depending on your painting style, the darkening of the color may not even be an issue because it’s so subtle. Beginners often don’t even notice it. Your style will also determine if this will be an issue for you.
For example, thin washes of acrylic paint won’t show this effect because it’s such a thin and transparent layer of paint. There’s less binder to lighten the appearance of the color. The example photo of the pouring medium at the top of this post is much thicker than a thin wash of acrylics so the effect is stronger.
An impressionistic painting would probably also conceal the way acrylics dry darker. An impressionistic painting consists of many daubs of color scattered throughout the painting. The modulation of color in this type of painting is often desirable.
Color matching is much more critical when a painting consists of large areas of flat unmodulated color. Pop artists such as Robert Indiana, Roy Lichtenstein, and Andy Warhol are good examples of artists who used flat graphic shapes in their paintings. If your paintings consist of flat areas of color then there are a few things you can do to make color matching easier for yourself. It’s not uncommon for artists to write down the recipes for the important colors of a painting so they will know how to mix it again if necessary. The green in the photo below is made from Diarylide Yellow, Phthalo Green, and Titanium White.
It’s also a good idea to mix more of a color before you run out. Matching a color is much easier when you compare wet paint to wet paint as explained below.
Save Samples of Wet Paint for Easier Color Matching
The best approach to precise color matching with acrylics is to save a sample of the important colors and keep them wet. You can store them in tiny plastic containers, or keep them in a stay wet palette. This will allow you to match wet paint to wet paint, before it dries darker. It’s much easier to match a paint sample this way because the color matching takes place before the colors darken.
In the above photo, the new green mixture on top of the palette knife is being compared to an wet sample of green that was kept wet on my palette for this purpose. The color on the knife is a very close match to the old batch of color and it will match perfectly when it dries.
Acrylic Paint That Doesn’t Dry Darker
Winsor & Newton professional line of acrylic paints don’t darken as they dry. They’ve formulated an acrylic resin that’s transparent when wet. In theory the colors should look the same when it dries. I have yet to test these out but I believe that it would eliminate the color shift problem. I should also mention that it’s only their professional line of acrylics use the transparent binder. The student grade Galeria paints behave like regular acrylics. I hope these clear acrylic resins will catch on with other manufacturers.
Acrylics Can Dry Lighter?
Aside from the clarity of the resin, the surface sheen can affect the appearance of a color. Most acrylic paint dries to a glossy surface and that’s when you’ll see the darkening affect. However, matte acrylics can dry lighter. This seems to affect dark colors more than light ones.
The photo above is an example of Mars Black from the Liquitex line of matte acrylics. The wet version at the bottom has a glossy appearance and it appears very dark. As it dries the matte finish makes it appear lighter. I believe this lightening effect has to do with the matting agents that change the surface of the paint. The surface of the paint looks and feels rougher and changes the way light reflects off of it. The glare makes the color appear lighter. The photo below is the same except a polarizing filter was used to eliminate the glare. Both the wet and dry samples now appear to be the same.
While acrylics tend to dry darker, the effect is often subtle enough that it’s easy to compensate for. Many painting styles will allow you to ignore the wet to dry color shift. If the wet to dry color shift is too frustrating for your style of painting, you can always try switching to professional acrylic paint from Winsor & Newton. Experimenting with materials and becoming familiar with their characteristics is an important part of improving your painting skills.