Brightness and Contrast in Illuminating Engineering

convey a very definite impression, with a good idea of expression, age, sex, character, etc. , even though the lines have made no attempt correctly to represent contrasts, colour, or many of the important details. It seems that we see not by light alone, nor by darkness alone, nor by contrast, nor colour alone, but by recognising the familiar geometry of the brightness and colour contrasts presented to us. Even a crude indication of this geometry may be sufficient to give a great deal of information either directly or by inference. Recognition thus depends upon .