Notes on Paint, Pigments and Binders

Paint & Binders PDF for download

The Paint

Acrylic paint comes with many ingredients and is made from acrylonitrile, a highly volatile toxic liquid used in creating acylic plastics and resins.

Acrylic paint itself is water based plastic designed to be stable, easy to use and safe to handle. Mostly it dries the same tone as when wet, with a sheen giving a more glossy finish, making your work look shiny, and easy and predictable to handle. There can be over 150 additives in the average tube of acrylic.

Pigment is the colour and binders are the medium usually liquid, which turn it into paint in that it binds the pigments into a liquid making it coloured paint.

Binders

Binders are used for all paint including car and house paint. They are the "glue" holding the paint together.

Colours might be made from a single pigment, several pigments or a synthetic combination of colours (hue). Better quality paint will have the pigment number or numbers. EG Prussian Blue is PB27.

Useless fact: a paint code say PB27, defines a range of formulation, "P" is paint, "B" is blue, ie PB27.0000 to PB27.9999, which is why one pigment maker's pigment might behave differently to another.

Paint made with a single pigment is important when colour mixing to keep the vibrancy, especially in those all important midtones. Don't insult yourself primarily using student grade paints.

The process of making paint is similar for all mediums. Small amounts of medium are added to the pigment until it becomes a paste. Some colours are “fluffy” meaning they dont easily absorb into the water so a wetting agent is needed. 

Dry pigment colours are made from minerals or chemical formulations

Pigments can be used to make any paint and inks

Paint is in three main parts

Pigment, binder and solvent

Tempera paint. 

Tempera paint is long lasting (hundreds of years) and dries pure matt.

In traditional use, namely byzantine icons, translucent layers are added to provide shading

There are two versions of tempera. Using the egg yoke directly then the oil version, adding linseed oil to the egg yoke and using a blender to combine both ingredients so creating an emulsion, ie oils, suspended in water. Otherwise known in cooking as Hollandaise sauce. 

The egg yoke  lasts about a week if left in a fridge but once dried is pretty much permanent.

Application

Egg tempera is fast drying and can't be “undried” so this affects how you paint. 

Egg yoke with oil dries longer, handling more like an oil paint.

Watercolour and gouache

The binder for watercolour is gum arabic. Adding Danish Whiting (calcium carbonate otherwise known as chalk) creates gouache. Gum arabic and Guache are perhaps the easiest to make and both are wonderful mediums.

 Distemper

 Distemper is glue size with whiting and dry pigment. 

Add size in a jar, then add eight times cold water. After a few hours it will turn to a jelly. Place the jar into warm water container and the size will disolve, plus a little stiring, and is ready to use. It is important that the size is not "cooked" as it will smell something rotton.

 Glue size is warmed, the pigment added and then applied warm to the support.

There’s around 17 :1 water to size ratio. Start with small amount of pigment first. Too much pigment and it will fall off.

It gives a pure matt finnish 

If Whiting is added it becomes Gesso with an eggshell matt finish. There is nothing else like it.

Mixing and amounts needed

Making up the whiting into Distemper

Break up the whiting in a clean bucket covering with cold water.

Leave the white to soak for 30 minuites before pouring off the excess water and beating into a smooth thick batter.

Make up the size in warm water then mix into the whiting.

Distemper dries light so this can take some getting used to

Binder to pigment ratios.

This is not an exact science and there's much trial and error. I'm always modifying mixtures according to what's wanted.

The main guidelines are to start off with 50/50 pigment binder. Extra binder and solvent can always be added later. It's important to get it properly mixed to get a highly pigmented solution, which can always be diluted. Sometimes the pigment might separate from the binder when stored but it can always be remixed. Prussian blue is very good at this.

Useful Terminology