Monday, March 6, 2017

How Much Water Can You Add to Acrylic Paint

"Strawberries," acrylic on aquabord panel, 6" x 6" by Kim Testone.
(I originally wrote this piece for my other technique blog, but as I'll be merging the two here I thought I'd share it again. Thanks!)

When I first began painting in acrylics a few years ago, I was very paranoid about how much water I could add to my paint. Of course I knew acrylic was a water-based paint, but there seemed to be a lot of diverse opinions around the Internet and in the books I read about how much water I could add to thin it down. Some people said no more than 30% water to paint, some said up to 50% water, and some even said they added up to 80% or more. What was the right answer? I didn't want my paintings to fall apart, but I was struggling to make the transition from the smooth blending capabilities of oil paints to the tackiness of an acrylic paint.

After lots of research and experimentation, I've learned that there isn't a single right answer, but rather a right answer for each circumstance. So I want to share with you what works for me. Note that in many paintings I will use more than one of these to work on various areas to get the right look and gain control over my paint. 


Option 1: The Watercolor Method

If you want to add gobs of water and work in super thin, washy layers, you can paint in the watercolor style. I first learned of this approach to acrylics in the informative book, "Acrylics The Watercolor Alternative," by Charles Harrington. When I use this method, I prefer to work on Ampersand Aquabord (an absorbent watercolor panel) but you can work on any watercolor surface you prefer. That is the key - if you want to be able to add as much water as you want, you need to work on an absorbent watercolor surface. Otherwise, if you try to work on a non-watercolor surface and water your paint down too much, you'll cause the bond between the acrylic polymer binder and the pigment to break, and the initial result will be that your paint may bead up and not adhere. It may also affect the structure of later layers of your painting and their bond to your surface.

 The "Strawberries" painting above is actually done on Aquabord. But in general, for my style of painting (many thin layers), if I'm working on a watercolor surface, I start out with multiple thin watercolor layers until the surface stops absorbing the water and then begin with my regular layering style - using a combination of water and acrylic medium. The paintings look pretty much the same at the end, but the watercolor method helps me get through the first several layers more quickly than in using other methods.

Option 2: Roughly 30% Water to 70% Paint

I try to avoid excessive texture in my paintings, and in some cases, working with straight water is a great way for certain areas to do that. When water evaporates from acrylic paint, it causes the paint to shrink slightly, so often, a little bit of texture during a painting session becomes barely noticeable by the next day (great for realist painters working like me, but undesirable if you are aim is to get lots of texture). To ensure that the bond between my acrylic paint binder and pigment isn't broken, I do try to stay within the manufacturers recommended limits of no more than 30% water to 70% paint. However, sometimes I go outside of this, if I'm trying to quickly soften an edge or because I work an area too quickly or just to get the paint to go where I want it to.

Do I panic? Never, because I have a secret weapon - I seal each of my paintings with one or more coats of undiluted gloss or matte medium, or a mix of the two,  at certain stages and at the end to ensure a proper adherence of every bit of my paint. It's sort of like applying a thin layer of glue over the whole painting, as you would in a mixed media piece. I also use it to help get achieve a more even finish to my painting surface, even if I still plan to apply a separate varnish afterward (I'll talk about this in a future piece). (EDIT: I've recently started using a permanent varnish sealer by Liquitex as well, which still seals the work but also adds a layer of added protection, even if I don't add a removable varnish.)

Option 3: Straight Matte or Gloss Medium


For some of my early acrylic paintings, I used almost no water because of my paranoia. I actually think this was a great exercise because once I gained some level of control over my paint using just paint and acrylic medium, adding water into the mix was a luxury! It is tough to do, but it does ensure the strongest possible bond. Think of it like a stretching exercise leading up to option 4 here.

There are, however, some circumstances in which I do still only use straight medium mixed with paint and no water, like when painting small lettering or sometimes when adding final details or glazing shadows.I do still occasionally use this method on a full painting as well, but because the medium extends the drying time significantly, it's a more time-consuming process for a full painting.

Option 4: The Perfect Medium

This is by far my favorite go-to painting medium, a formula which I came up with myself, but I'm sure many artists far smarter than me came up with long ago. So here it is: make a mix of 70% matte or gloss medium with 30% water. Mix as much or as little with each brushstroke as you want. Voila!

We're visual people, right? I made you a visual!

This simple formula makes everything so much easier during the painting process and provides me with a perfect level of control over my paint. Why does this work? Acrylic medium is essentially acrylic paint with no pigment. I can add as much acrylic medium to my paint as I want. So, if this helps to thin my paint and adjust its viscosity, and if water does as well but I shouldn't add too much, why not just add the water to the medium (in a proportion that will retain the medium's binder)? Then I get a thinner medium that moves my paint more easily, and I don't have to worry about how much water I'm adding to my paint.

For my approach to realistic acrylic painting, this is a great solution. I mix up enough for my painting session and store it in a Diamond Daily Mini Cup with a lid and keep it on my palette or on my easel. (I use these cups for a variety of purposes in my paintings, which I'll discuss in future posts.) 

Why I Don't Use Acrylic Retarder or Open Acrylics

Some of the main reasons I stopped using oil paints were because of the technical rules adding mediums and because I was tired of constantly having to take tweezers to my wet paintings to get rid of pet hair and dust. That's why I don't use acrylic retarder or Open acrylics. Both of these methods aim to extend the working time of your paint, making it behave more like oils. But acrylic retarder can cause adhesion problems, and Open acrylics attract even more dust and pet hair than oils did for me. While I'm sure some artists have found success with them, I've found them unnecessary and overly complicated.

Final Thoughts

When in doubt, seal it! As I mentioned, I seal each and every painting with an undiluted coat or multiple coats of gloss or matte medium and/or a coat of Liquitex permanent varnish. I never worry that my bond won't adhere years down the road.

I personally also use a really high quality paint - usually M. Graham Acrylics or Golden Acrylics - because I know that these paints aren't chock full of fillers or junk that is unnecessary, and I have confidence in their archival properties.

But the best advice I can give to any aspiring painter is to simply paint. Experience will be your best guide.

I hope this article has been of some help to you! Happy painting!