The binder is what makes pigment stick to the paper. Watercolor binder is made from water-soluble tree gums. This particular listing uses gum Arabic, which is harvested from one of two types of acacia trees that grow in Africa.
It can also be made using the gums from peach, cherry, and plum trees. I haven’t done any studies on how these gums affect the stability or permanence of pigments, however, the ability to use a locally foraged ingredient rather than one imported from far away, is a temptation. Eventually, I’ll do some comparison studies and research this option more.
When I make my own watercolor binder, I usually make several bottles and sell the extra. One bottle lasts me for several months if kept in the refrigerator after opening.
Watercolor Binder Quality Control
I test each batch to make sure it performs to my own expectations. Things I’m concerned about include whether it dries without being tacky, wets easily enough (different pigments have different personalities, and some might need more time to wet… or ‘wake up’), minimizes cracking, etc. But the most important things I note: are the colors vibrant as expected, and will it smudge after it dries (it definitely should not). If those two criteria are met, I am happy.
How to Use
When making paints using dry pigment powders, you’ll need to get a feel for how much binder each different type of pigment needs. If your paints crack when drying, try adding a little more binder during mulling. Pour thin layers at a time into the pans and let each layer dry thoroughly. To make sheer paints with a little more gloss, I make a thinner paint. Sometimes I also pour up a pan of just the media so that I have a pan on hand if I want to add a little gloss to highlights in my paintings.
DIY
Here’s my general recipe if you’d like to make your own. If you make enough volume and use heat sealing lids, you can preserve them in a water bath just as you would can jelly or preserves.
Using powdered food-grade gum Arabic:
Makes one cup:
- 5T powdered gum Arabic
- 1/8 c honey
- 2 drops clove essential oil (not fragrance oil)
- 1 cup water
Boil the water. Put all of the other ingredients in a bowl. Once the water is boiling, add a little to the bowl so that you can stir the ingredients with a fork into a paste. Try not to let it make lumps. Slowly add the rest of the water while stirring. Bottle it while hot and refrigerate once opened. My bottle of media lasts months in the refrigerator.
Using whole gum Arabic tears/resin
- Start with a quart jar
- Add 1″ layer of raw gum Arabic resin
- Fill to curve of neck with boiled water
- Agitate to dissolve the resin once the water cools enough to handle
- Strain
In another container, add 1/10 volume with honey, fill the rest with your gum Arabic solution.
Add 1-2 drops of clove or cinnamon essential oil.
Usually, I make this in the evening. I fill the jar with gum chunks to the bottom mark. Add sterilized water to the second mark. Let it sit overnight to dissolve, and turn the jar every once in a while to help it all get wet.
The next evening, add more water if necessary to meet the second mark. The photo shows it right after I took it out to add the extra water. As the gum dissolved, the volume settled a little. Then add the honey.
After that, add a dash of essential oil of cloves. Supposedly this helps to keep mold and bacteria from growing but I don’t know if it works or not.
Then filter it all through the same sized sieve used below for sifting the powdered pigments. Store the media in a clean jar in the refrigerator and use as needed. If you have any gum left undissolved in the bottom of the ‘dirty’ jar, don’t throw it out. Just leave the lid off and let it dry out. Use the same jar just as it is, residue and all, for making the next batch.
So there you go! This is my way of making media for handmade watercolor paints. Let me know if you try it how it worked for you.