When we buy our paint colours at the art supply shop we take it for granted that the contents of each colour come from remarkably diverse sources. Burnt wood, pregnant beetles, semi-precious stones, metals....it's no wonder that some strange behaviours may manifest with some of these colours!!
Here are 6 strange behaviours that are worth taking note of in your pigments.
6 More Wacky Behaviours of Pigments as provided by Winsor + Newton:
(i) ‘A' rated in full strength may fade in thin washes
(ii) Cannot be relied upon to withstand damp
(iii) Bleached by acids, acidic atmospheres
(iv) Fluctuating colour; fades in light, recovers in dark
(v) Should not be prepared in pale tints with Flake White, as these will fade
(vi) ‘A' rated with a coating of fixative
My favourite is (iv) which is basically like reverse glow-in-the-dark ! So if you notice any funny behaviour happening with some of your paint colours look further into the characteristics of the pigments it contains.
Winsor & Newton has developed this system (i) to (vi) to notate any paint colours that they make that have these characteristics. Other brands don't use this system.
Many colours are man-made - created in a lab, they have chemical-sounding names like Phthalocynine Blue. But many of the pigments are naturally still naturally sourced. Some of them come from the strangest sources so it's no wonder that they act so surprisingly. Think about that next time you are painting!