Let there be Light

It's amazing to me how important light is to our visual perception system, even though we are often not consciously aware that we are looking at light (i.e. When we are in the shadows of a room). Light is one of the “first causes of perception” (Arnheim, pg. 303). Without light, we cannot see.

Our ability to distinguish the luminance or brightness of an object is related to the context of what's around it. For instance, the man in figure 224 (Arnheim, pg. 308) is seen as in shadows relative to the woman, rather than having darker skin than the woman. One of the reasons for this interpretation is that his cloak is also engulfed in shadows, showing that the whole body is situated in a place of low light in the picture. If his clothes were not shadowed, then it would be more arguable to interpret his darkened face as darker skin.

I am not an artist (other than two art classes taken in high school), so I'm incredibly impressed, knowing now, how hard it is to separate the luminance and the color in our perception, that so many artists manage to balance the two perfectly (especially Leonardo Da Vinci). Jean-Auguste-Dominique Ingres' picture of Princess Albert de Broglie (Arnheim, pg.126-127) is impressive. The caption is right – it is difficult to tell that the black and white is not the photograph of a person; in fact, I think it is only the unnaturally white skin that gives it away. The dress is captured perfectly with the way that light reflects off the shimmery material.

Livingston outlines how our visual system is adapted to perceive more luminances even though the actual perceptual ability of the individual parts of our system are limited. The center/surround system allows us to easily distinguish the difference between sharp contrasts. Gradual changes are overlooked when distinct changes occur. In this way, we increase our ability to see luminance differences.

I am intrigued about the correlation that Livingston draws between luminance contrasts and depth perception in paintings. She says that the Cathedral paintings that look flatter are also the ones that have little luminance contrast in the analysis of the luminance profiles. This is due to the fact that the Where system is colorblind and sensitive only to luminance changes in seeing shapes from shading. “Thus, a low luminance contrast alone stimulates the Where system but not the What system” (Livingston, pg. 128).

The two paintings by Monet (Livingston, pg. 132-133) demonstrate what happens when the artwork stimulates primarily the Where system. The objects in the picture are not distinct, and it is only after studying the picture for some time that one can distinguish the objects at all. Despite the fuzzy quality of the objects, the depth relations of where the blurry objects are situated is clear. This is due to the low luminance contrast and lack of color contrast.

I found it particularly striking that Andre Derain understood that by utilizing the luminance differences to show depth, an artist was freed from using descriptive colors to work with expressive colors. This ability is due to the colorblind-ness of the Where system which sees depth.