Tuesday, December 21, 2010

The science of lightness perception - part 6

In continuing to set the stage for my review of the new PercepTool2, and realising that many don't yet have George DeWolfe's Book, B&W Printing, here I'll finish presenting some of George's glossary terms.

Remember, George notes that many of the words that he uses have additional meanings in other contexts, but are used here as they relate to the science of lightness perception. I'll present the basic information. Readers are encouraged to get George's book in order to dive into the details.

Scale normalization rule: the perceived range of grays within a framework shifts to a 30:1 range (in brightness) from highlight to shadow relative to the actual physical range given the framework.

Size: the greater the size of a local framework, the more important it is in the image.

Value: refers to where a black, white, or gray tone lies along a light to dark continuum.

Visual perception: the process of acquiring, interpreting, selecting, and organizing what we see.


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