Layers in Compression

A collage is an example of layers that seem to be in ‘compression’; layers placed one on top of the other, when in fact that is not the case. Unlike perspective sketches, ‘depth’ in a collage is perceived by the contrast and play of colours between each other and each layer. Darker colours, particularly black, appear to recede into the ‘back-ground’ layer, while lighter colours come forward. However, the opposite is true in sketching; strong details in the fore-ground layer and less in the back-ground.