Why and How to Use Watercolor Mediums

Watercolor using Distilled water and Mediums 

¬† So with watercolor painting for some reason there is a lot of misinformation out there and other information that is completely lacking. Three of the most misunderstood subjects is using watercolor mediums and the use of distilled water vs. tap water. Let’s start with using distilled water to thin your paints. I have heard the rumors that using distilled water is superior to using tap water since I began watercolor painting back in high school. I have continued to hear it over the 20 or so years since then. I finally broke down to experiment with the possibilities of using distilled water. First off distilled water is slightly more acidic than tap water the higher ph could potentially be detrimental to your watercolor paper. That not withstanding I experimented using distilled water on different papers hot pressed, cold pressed, and rough watercolor paper. I also used distilled water in several watercolor painting techniques including gradient washes, flat washes,wet in wet, and wet into semi-wet and so forth. The verdict is there is no difference between tap water and distilled water. In fact distilled water didn’t perform as well as tap water. So in watercolor painting tap water is just fine. Let’s move on to watercolor mediums what they are for and how to use them.

Watercolor Mediums

Why and How to Use them Gum Arabic

Most watercolors contain a portion of gum arabic. It has the consistency of honey or light corn syrup it is used as a binder for watercolor paints. As a medium gum arabic increases the gloss and transparency of watercolors. Gum Arabic also helps slow down the drying time of paint giving you more time to work with you washes.

How to Use it:

Never use gum arabic straight out of the bottle. Always use it with water. At the very least use a small water resevoir with 8 oz water about 20 drops of Gum arabic. I also will sometimes use Gum arabic in my main painting water. Then you just use your water the same as you would if it didn’t have gum arabic. Something to be aware of if you use gum arabic your paint will lift off the paper more easily,so if you plan to use several layers of colors over other colors don’t use gum arabic.

Ox Gall Liquid

Ox gall increases the wetting properties and flow of watercolors with a few drops to your painting water. The colors will soften and blend together easier. The medium can be useful for ‘marbling’ or creating textures. It will also set your colors into the paper and make them harder to lift. If you want to create paintings with several color layers ox gall is the way to go.

How to Use it:

Using about 8 oz of water add 10 drops ox gall liquid. Use the medium to wet the paper for wet into wet or wet into semi wet techniques painting techniques.

5 Responses

  1. Do you have any information on gel mediums to mix with water before using either watercolour or gouache? I’m going to the Antarctic and have been told a gel medium is useful. Many thanks

  2. I just wanted to add to your discussion of tap vs distilled water. Unlike you I don’t think I’ve ever known any artist to say that using distilled is superior in as far as how it makes their artwork better or worse. The only reason I’ve heard to use distilled over tap is to avoid mold on the palette. This especially true when the watercolors contain honey. Some home tap water (and/or old piping systems) contain forms of bacteria not harmful to humans, but that interact with the honey contributing to the formation of mold. Apparently the distillation process kills the bacteria… I doubt I said anything you anything you didn’t already know!

    1. I appreciate you pointing this out. I believe it helps forward the discussion. My palette is flat without color reservoirs so my colors dry out in few hours instead of being wet for days so I never have personally had problems with mold. I do however, know people that paint in watercolor every day using a palette with paint reservoirs and the colors are always wet or moist and so I have seen mold grow when this is the case. I was unaware that distilled water helped thank you for the tip.

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