Substrate Induced Discoloration
Substrate Induced Discoloration or (SID)
Acrylic mediums (especially when thickly applied) have the ability to draw out impurities from the support (surface) they are painted on. Gesso priming will not prevent this from occurring. The impurities in the support cause clear gel mediums to take on a yellow to deep brown cast. Pre-washing your canvas will remove impurities and prevent SID.