Sunday Secrets #33

 This entry was originally posted on Sunday, September 2, 2012

A couple of weeks ago I discovered a question in the comment section of Sunday Secrets #21

which is about gum arabic, the binder in watercolor paint.

 

The question is 

I have got Gum Arabic granules, how can I make binder from these granules?

 

That is a good question and one that I am not entirely sure of how to answer. I have never worked with the granules, just the liquid form.

However, I did some research and I hope what I found can help.

 

First of all, gum arabic is easily dissolved in water (hot or cold) when it is in powder form.

It might also be easily dissolved as granules.

You can give it a try.

If not, you might be able to grind it into powder form, the same way that pigments are ground.

With a mortar and pestle. 

(but NOT your kitchen one, please use one set aside just for your painting)

 

A good ratio is 1 gram of powder dissolved into 2 ml of water.

This should flow easily.

I would suggest using distilled water.

(This is what I use when grinding my own pigments. It has fewer impurities)

Now you will have a liquid form of gum arabic.

 

Once you have the liquid gum arabic, you can add it to powdered pigment or dried out watercolor paint with a dropper.

A good ratio for this seems to be 3:1 or 4:1 of water to gum arabic

(3-4 drops of water to one drop of gum arabic)

 

Add the gum arabic and the water to the pigment until you get a nice creamy consistency that you can paint with.

 

Extra gum arabic can be added to your paint to increase the flow and to make it glossier.

However, too much gum arabic will cause the paint to crack and flake off. 

Sunday Secrets # 21

 This entry was originally posted on Sunday, June 10, 2012

Today's Sunday Secrets is a question from Hannah in Vancouver, BC

 

She asks, "What is Gum arabic and why is it in watercolor paint?"

 

That is a good question.

Gum arabic is a gum made from hardened tree sap from the acacia tree.

Gum arabic has properties that make it glue-like and is a binder used in many things since it is also edible.

You would be surprised to know how many things it is used in!

Soda, candy, and postage stamps, for instance.

 

Since it is a natural binder, it is used in watercolor paint to help the pigment bind to paper.

Without a binder, the pigments that are in paint would just brush off and act like chalk.

That is why we need binders in paint.

To make sure it stays where we put it.

 

Gum arabic is one of the oldest binders for paint.

Another wonderful binder is egg which is used in egg tempera.

Oil paints use a drying oil (the most common being linseed oil) that has been boiled with resin as its binder.

Acrylics, which have only been around since the 1950s, use an acrylic polymer as the binder.

 

More information on gum arabic can be found  here