Binders are the vehicle in which pigments are suspended to make paint. They help the pigment create a film and bond with the object on which it is painted, can make a paint flow properly, add body, and increase durability.
There are many natural binders that were used by NW Coast Indigenous people for making paint:
These binders each impart distinctive properties to the pigments with which they are mixed.
All fat-based (lipid) binders darken and even alter the color of pigments. They create reflective finishes similar to manufactured satin paints.
Bone marrow is a lipid binder and behaves like other lipid binders.
Hide glue darkens colors slightly but does not create a reflective finish; the finish is light-absorbent and has a velvety, matte finish. Hide glue paint can be thinned with water and has especially nice paint ability.
Vegetable juices, saps and resins each have their own characteristics that must be tested to discover how they behave with each pigment.
Water has been used with pigments for thousands of years on the NW Coast and proves to make a surprisingly durable paint with the color remaining true. The finish obtained is matte and light absorbent.