Mediums to add to your paint

 Ox Gall, Blending Medium, Gum Arabic, Glycerine, and Granulating Medium

Ox Gall

This is usually part of the formula for your water color paints. It is safe to use with your watercolor brushes. It is designed to improve the flow of your paints. It is considered a wetting agent, dispersant, and surfactant. 

 Use only 3-8 drops in a cup of your clean water. You will most likely need it on paper that is highly sized or heavy (300 lb) which resists water. Here is the most complete information that I have found on ox gall:

https://www.greenleafblueberry.com/blogs/news/how-to-use-ox-gall-in-watercolor-painting#:~:text=Ox%20gall%20is%20usually%20in,sold%20as%20a%20watercolor%20additive.&text=Ox%20gall%20is%20used%20in,aid%20in%20wetting%20your%20paper.

You should experiment with it for fun. You may decide it is super useful or that you just don't need it at all.

Blending medium

This extends the drying time to give your paints a little more time to blend and reduce the hard lines you get when the paint dries before you have time to blend or soften edges. It can be used with your regular brushes, and is used either slightly diluted with water or by itself to wet your paint. You can also wet the paper with it, then immediately paint on top of it.

Blending Medium is useful in a dry or hot climate, where your paper and paints may tend to dry too quickly. Like in the winter when the heater is on and the air tends to be dry. Or en plein air with hot dry temps. It is also helpful when you just need a little more time to work on an area. There are also some papers that absorb the paints too quickly and don't give you time to blend.

Gum Arabic

Because this is part of your watercolor formula, it is safe to use with your brushes. Dilute with water, dip your brush in it, then pick up the paint. It can enhance the brightness of your color, and slightly increase wetting time. You can also use it if your paints have begun to dry and crack.

https://www.artistsnetwork.com/art-mediums/watercolor/the-secret-of-gum-arabic/#:~:text=Gum%20arabic%20is%20the%20binder,linseed%20oil%20with%20oil%20paints.

You should not use gum Arabic thickly. It will cause the paints to become brittle.

 Glycerine

This is used in so many products, from make-up to candy. I use it to revitalize paints that have begun to dry and crack. Glycerine is a plasticizer, and makes the paint flexible, and sometimes adds to the glow. It serves the same function as adding honey to paint, and makes it creamy and easy to work with. 

While many paints will dry, if they begin to crack, it means they have lost some of its binder and will not spread or adhere to the paper as well as when they were new. I use a dropper with a tiny bit of glycerine to revive them. The video below compares using honey and Glycerine to improve your paint.

 https://www.google.com/search?q=using+glycerine+in+watercolor&rlz=1CATRIY_enUS1088&oq=using+glycerine+in+watercolor&gs_lcrp=EgZjaHJvbWUyBggAEEUYOTIHCAEQIRigATIHCAIQIRigATIHCAMQIRigATIHCAQQIRifBdIBCTgyMzNqMGoxNagCCLACAQ&sourceid=chrome&ie=UTF-8#fpstate=ive&vld=cid:15fa71bf,vid:YMFxHpUoK3k,st:282

I would also use Glycerine on a cheaper paint that doesn't flow as well as an artist grade paint. 

I have never had Glycerine go bad on me. And it's pretty cheap.

Granulation medium

PAY ATTENTION to this : DO NOT mix your paints that you add granulation to in your palette. You do not want to get it into your other paints, so you need to mix it separately.

Granulation medium is used to cause a non=sedimentary color to granulate. Some paints naturally granulate: burnt sienna, French ultramarine, some other blues. But pthalo blue is smooth and staining, sinking into the grains of the paper. Adding a little granulation to the puddle mixed with paint and water will cause it to separate and create texture. See this Winsor Newton video:

https://www.youtube.com/watch?v=1zlL8NNQx-I

Christmas Cactus project

Today's project is one I've used before, but not to demonstrate the use of mediums. I like it for newcomers especially because it demonstrates several key watercolor concepts:

    Color mixing and blending

    Wet into wet technique

    granulation

    creating shadow

    lifting

    limited palette

Choose 3 basic primary paints, a yellow, a red, or a blue

(I chose a medium yellow, magenta, and cerulean, with later addition of French Ultramarine)

I used wet into wet techniques on each stem. On the left stem, I just wet it with plain water, then added blue, then yellow, then magenta, with some blue on the bottom, allowing each color to blend into the next.

With the next stem I used blending medium in the water with the paint.

On another stem I used ox gall with the paint.

And on the last I tried some gum Arabic in the water. 

After it dried, I worked on the pot. I created a puddle of paint - burnt orange--and added granulation medium to it. I washed over the entire pot (using a flat brush) with the granulated paint. On the right side I added some French ultramarine (it is self granulating) to create a bit of shadow, while wet. I dried it completely.

When finished I did the table. I made a puddle of red (non-granulating in most circumstances) and added the medium, just a few drops. I painted the table, then added some blue near the pot to create a shadow.

To finish, I wet the dirt area, dropped in burnt umber, then dropped in French, and while wet, I added salt.

I LIFTED the light around the top of the pot edge. Lifted the vein that goes through the centers of the stems. And then I created a small hard dark on the far right blue leaf to separate the two leaves. I also darkened the shadow beneath the pot and added a thin dark shadow