Sentence:  These areas by virtue of their abrupt density of pattern , stated the literal surface with such new and superior force that the resulting contrast drove the simulated printing into a depth from which it could be rescued - and set to shuttling again - only by conventional <WSD>perspective</WSD> ; that is , by being placed in such relation to the forms depicted within the illusion that these forms left no room for the typography except near the surface . 
Meaning of the word marked with <WSD> tags:  the appearance of things relative to one another as determined by their distance from the viewer