Tuesday, October 12, 2010

Is Using Water with Acrylic - Good or Bad?

There seems to be a myth that you aren’t supposed to use water with acrylic, and then there’s another one that you should always use water. This issue about water was something that really intriqued me when I first starting using acrylic paints.

I address this issue in my book, Acrylic Revolution. The book has lots of recipes and techniques and the idea of when to use water and when not to use water becomes more clear. But here I’ll write about it more specifically and in depth.

Basically water is not a bad thing to add to acrylic. However, there are some basic issues that when understood will help you decide when to use it and when not to use it - when it helps your work and when it works against the effects you are trying to achieve.

First, lets look at what makes paint. Generally, all paint is made of 2 basic components: pigment (for color) and binder (to make the pigment usable as a paint). The binder is what identifies the paint. For instance, take some pigment and add oil – now you have oil paint. That same pigment mixed with milk makes casein, with gum Arabic makes watercolor, and with polymer (or plastic or acrylic) you get acrylic paint.

So there’s pigment and binder, and then there’s the solvent. Each medium has a solvent that will break it down. For acrylic the solvent is water. Acrylic without water (just pigment and polymer binder only) will produce a paint film layer that looks juicy, glossy and substantial when applied over any surface. The surface could be absorbent or non-absorbent, colored or white. It doesn’t matter, because once you apply the undiluted acrylic on top the paint film will all look the same. You can add up to 20% water to acrylic paint and it will still have that glossy paint film, it will just get a bit thinner.

However, it’s a very different story when you add A LOT of water to the paint. When you make a 1:1 ratio (equal parts of paint and water) or even more water that that (I like 80% water to 20% paint color), we can call this “overdiluted” paint. Once acrylic paint gets overdiluted with water it will look totally different depending on the surface absorbency that it is applied to. For instance, a diluted acrylic paint applied on an absorbent surface like watercolor paper will have a matte, soft, muted evenly applied layer of color. This same diluted paint on a non-absorbent surface will look very crazy, puddling up in places with some interesting effects. (All this is in my book). So it’s TWO things that work together to create the interesting water effects – overdiluting the paint with water along with changing the absorbency of your surface. To change the surface you first apply some type of paste, gel or ground that makes it more or less absorbent than just the plain old gesso primer usually found on store-bought panels and canvases.

So, here are some key ideas: (1) use acrylic without any water at all for a rich, glossy, plastic, high coverage layer. (2) Use up to 20% water in acrylic paint to slightly loosen the paint, make it a bit more fluid to get evenly applied linear effects and decrease texture (3) Combine 80% water to 20% paint to get an “overdiluted wash” – and now use this on a selected surface (absorbent, non-absorbent, textural or smooth, colored or uncolored) to get a specific effect. (4) Use retarders and glazing liquid or the new “Open” slow drying acrylic to keep the acrylic from drying fast. Do not use water all over your palette to slow the drying or you won’t be able to control how much water is going into your paint.

I do think the whole water issue with acrylic is a bit confusing. Adding water is not bad. Its just that when water is used haphazardly and uncontrollably (spraying palettes with water to keep it wet, or not blotting the brush after washing it) this reduces the range of possible effects you could otherwise obtain. Again, the most important thing to remember is determining how much water you want in your paint depending on the type of effect you are looking for. The more water you add, the more important your choice of surface is to get certain effects.



Anonymous Anonymous said...

thanks for explaining this Nancy, its one of those things you think about, but are not always aware of the impact on one's painting.

take care,


October 12, 2010 at 6:01 PM  
Blogger PaintingLover said...

haven't tried it yet. but your explanation is great

October 13, 2010 at 9:40 AM  
Blogger m x X x said...

I paint over canvas gessoed and sanded at least three times. I usually use hint of water using brush, no water with knives, and spray with 100% water for minutes for washes. I have used a bucket full of water for kind of wash I might want at times, letting the water drain, hitting canvas hard with water jets and let water rip the rich layers of thick acrylics underneath. I love to paint...and wash and paint (and wash). I am reading this because I am a bit concerned about how this heavy use of water could have been affecting longevity of my work. I am kind of reassured, many thanks, though I think I'd keep using water to say my story even if doesn't stay forever! Thank you Nancy!

December 26, 2013 at 8:47 AM  
Blogger Nancy Reyner said...

It sounds like you are taking good advantage of the wash effects using over diluted (higher ratio of water to paint) acrylic. As I mentioned this is the way to get some interesting unusual watercolor type washy effects. And yes, what you are doing is fine. A final coat of an archival varnish will help keep your work looking the way you want it for longer. Washes do decrease the lightfast rating of some colors, and a coat of varnish with UV protection will help this.

December 27, 2013 at 4:15 AM  
Blogger alexis said...

It's important to note that using your 80% water to acrylic paint ratio will break the binding ability in the paint. It's fine to use as a wash on watercolor paper, but a canvas surface will peel after some years. Very bad for certain surfaces.

April 16, 2016 at 12:16 PM  
Blogger Nancy Reyner said...

Hi Alexis,
Thank you for your comment. However, I disagree. If you use student grade acrylic paints, and/or canvas with gesso already applied, you will have adhesion issues. If you use fine art quality acrylic paints, on a canvas using professional gesso made for acrylic, you can apply washes (heavily diluted paint with water) without any bad effects. Always use filtered water. If you use tap water, the chemicals and impurities can effect the stability of the wash paint film. Canvases that are purchased already gessoed usually use cheap gessoes, which will peel after some years REGARDLESS of whether your acrylic paint is diluted with water or not. In conclusion, washes of acrylic paint, using filtered water, high quality paints, appropriate gesso on canvas, and sealed with a varnish as the last painting layer, will not have any ill effects.

April 16, 2016 at 12:28 PM  

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