It is an old video, but I’ll answer your question anyway: interference colours are designed to go on top of other colours to create colour shift effect.
Layer the interference colours on top of regular dried watercolours. Use them as highlights, change your regulars into new colours with a little shimmer in another colour etc etc. TONS of options!
To avoid destroying your brushes,always use them opposite of the direction the bristles point (eespeciall when you pick colour). It will destroy the points of your round brushes eventually,as also the hair will get shorter over time.Thanks a lot for 5he swatches.keep up the good work!
Interference colors change when the angle of light changes usually with something aproximating the compliment of its usual color. It shows up more over darker areas of your painting.
