Photoshop Lab Color- P7: LAB has a reputation for enormous power, yet virtually all reference materials that advocate its use illustrate its capabilities with a single class of image. This chapter introduces the basic LAB correction method and explains why it is so extraordinarily effective. if you happen to have a picture of a canyon. | 9 The LAB Advantage In Selections and Masking The A and B channels may seem blurry and shapeless but they re often the beginnings of the best masks. Objects that can t be resolved in any of the RGB channels are sometimes clearly defined in the A and or B. Sometimes the strange structure of the AB channels even lets us select the ambient light. y luve wrote Burns is like a red red rose that s newly sprung in June. While much is to be said for the creative use of flowers in romance and while redness is ordinarily a virtue Figure is too much of a good thing. It s not a rose any more all detail has vanished in an out-of-tune melody sung unsweetly in a chorus of cacophonous oversaturation. The rose appears here because being so different from its background it s probably the easiest object we d ever have to select in a photograph. But before doing so I d like to fill in one hole in the first half of the book. The objective of manipulating the A and B channels is usually to increase color variation and to make certain colors brighter and purer. Basic AB curves accomplish this when we make them steeper by pivoting them counterclockwise around the center point. On rare occasions of which this is one we need to do the reverse to suppress colors. Steepening the AB curves wakes colors up flattening puts them to sleep. To reduce the intensity of the colors we pivot the curves clockwise. Figure had so many reds that were outside of the CMYK gamut that they all closed up when the file was converted. Figure B with a contrast boost in the L channel and the AB values reduced is a better match to what can be printed. Now back to our regularly scheduled program. When we select an object in Photoshop parlance we allow ourselves to change it whereas anything that isn t selected is locked. We can also make partial selections which reduce the effect of any move applying it less than on a fully selected area but more than on an area that isn t selected at all. We used .
