Luminosity Vs. Sparkle

   
 If you want the eyes to twinkle, the fruit to gleam, the bottle to shine, then follow Rembrandt’s example. Look at the hilt of his cane. It sparkles. Its sparkle follows a formula; any small area of light surrounded by a larger area of dark offers the promise of sparkle. We are attracted to contrast. The greater the contrast the more brilliant the effect. So, a very small area of light will appear to shine when surrounded by dark. If you were to place a photometer on the light area you could discover that it measured a quantity of reflected luminance that was equal to or less than the light in other areas in the painting but the sensation to the viewer is that the small patch of light appears brighter. We look at areas selectively and in small bits called foveal saccades. We experience brightness as a relative experience. When an area of light expands in size, then it appears to diminish in brilliance. We notice light by its contrast against darkness. This is true metaphorically with everything. If you want something to seem bigger or younger or darker or bluer just place it against its opposite condition.

Notice in my photo that the rocks appear to sparkle with light but the larger water territory in the upper right is merely bright, not sparkling. It is too large to sparkle. Notice in my painting that the foreground lights juxtaposed against dark edges appear brighter than the blended middle-ground lights even though a photometer would disagree. This is because they are broken into smaller patches of light and surrounded by more contrast, more intense darks.