Friday, January 22, 2016

Wet vs Dry - Acrylics Dry Darker - The Proof!

So one of the things we deal with when painting with acrylics is that they dry darker then they seem when they are wet.

How many times have you walked away from a canvas thinking your highlights are just right, your value shifts between light and shadow are just right. And a couple of minutes later they are gone! I know I have!

This is because the acrylic medium that is mixed with the pigment to make acrylic paints is a little opaque when wet - and then drys clear.

It's hard to pin this down because it isn't the same for all colors, so I thought I would try an experiment.

I used gessoed canvas and these paint colors in Golden regular heavy body paints:

Napthol Red Light
Hansa Yellow Medium
Ultramarine Blue
Titanium White

I made rectangles of each color, using a double layer so I would be sure to cover the white canvas.

I added white to these and made more rectangles of paint in different values of the same color.

After letting them all dry, I used the exact same mix and brushed the wet paint over the dry and took a photo immediately.

The dry paint is on the left, the wet paint is on the right.

So this is what I saw:

First with Napthal Red Light:

  The first thing you can notice is that there is virtually no difference with the pure tube color. In fact, the paint on the right - which is wet - looks a bit darker. Because this is a fairly transparent paint, and there is still some of the white of the canvas showing through on the dry paint. The wet paint added a third layer and covered the canvas more.

The middle one with white added also shows very little shift (the wet stroke is always on the right)

The last sample, with quite a bit of white added shows a significant shift in value from dry to wet. It's pretty obviously lighter on the right!

Next with an Orange made by mixing Napthol Red Light and Hansa Yellow Medium

You can see again that the pure color, with no white added shows no discernible shift. In fact it looks a little darker again. I went one more step, adding even more white in this one.  You can still see the shift on the lightest one, but I think the second and third show a more distinct shift. This really does affect your outcome, especially when you are adding highlights. I can't tell you  how many times I've added light highlights (I thought) only to come back and they seem to have disappeared!

Another interesting thing to note on this sample. My mixture of red and yellow to make this orange looked very similar to the red in the pure form. But notice how different the color looks when you add white?

Next is Hansa Yellow Medium
Again, no visible shift in the pure tube color. Even in the lightest version, the shift is not that big. Interesting! Hansa yellow is not a strong color. In mixes you have to add proportionally more of it to get it to show up.

Next is Green made by mixing Ultramarine Blue and Hansa Yellow Medium

 I did 4 values again with the green. It's a color we use a lot in landscapes, so I wanted to see more variation. Again - no shift in the tube color. With the center samples showing the most shift. Though when you look at that last one, there still is quite a shift. The wet part looks almost white, while the dry is distinctly darker. That darkest green is sure dark isn't it? Great for making rich darks in your landscape.

Ultramarine Blue

 Again, a fairly transparent color from the tube, so even after 2 coats of paint on the left, the wet paint on the right is still darker because it is covering more of the canvas. Our pattern seems to be pretty consistent! No wonder my sky always looks too dark!!

Lastly, a Purple made from Ultramarine Blue and Napthol Red Light

Again - what a great dark, right? It almost looks brown. And yet add a little white and it's a beautiful color! And again, the lighter - more white added - the more visible the light dark shift is.

So, this was a great experiment for me! I say all the time in my classes "Remember,  acrylic paints dry darker!"  And now I can show you just how much!

  • So the pure tube colors don't shift much. In fact the transparent ones may look lighter - just because there is more of the canvas showing through and a double layer of the same paint will cover more.
  • The more Titanium white you add, the greater the value shift from wet to dry!
  • When you mix those very light colors, like for sky and highlight, don't be afraid to go very very light! What looks almost white wet will dry obviously darker!
Good to know! Hope this helps you visualize this shift better...


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  3. As always, thanks for sharing your experiments with us! -KC

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  6. Karen, Whilst looking at some Acrylic paints I saw in jars, not tubes, manufactured here in the UK by Pip Seymour,, I thought Id have a further look into his paints and found some interesting information. In order to create consistent textures, light-fastness and drying times the medium added to the pigments may change for each color. This happens in all paints. I tried to find out more and came across a book. The Painters Handbook" by Mark Gottsegen. Maybe of some use in understanding how paints change color when drying. It may be of use anyway it seem full of info on the technical aspects of painting. "Mark Gottsegen is the chairman of this government committee to set standards for the performance, quality, and health labelling of artist's paints and related materials - on light fastness and the general longevity of art materials are provided" Have a look on Amazon

    1. Interesting John. Knowledge is a good thing! And then there is just the practical aspect of how the specific colors on your palette work. I find myself glazing over when I get a lot of technical information, haha. I think I have seen that book actually, I'll have to go check my bookshelf. Thanks for letting me know!

  7. Great articles and great layout. Your blog post deserves all of the positive feedback it’s been getting.
    Wall Lights

  8. Thanks Karen. I watched a DVD by Nancy Reyner on color mixing and she pointed out the difference between mineral and modern colors when adding white. Going from the masstone to a slightly tinted color makes a bigger difference in the modern colors (i.e., the ones with the difficult names like Naphtol red) than the older mineral colors (like Ultramarine). A little white really makes the modern colors pop. This might explain the large change in your purple mix, as the big shift from adding white may be due to the modern red you are using.