Digital Light & Color

PW 8.447
Hello.
a) Color curves default to HSV | V color space; Change to RGB and this defaults to Blue. Change to HSL | Hue; change back to RGB and now default is Red. RGB Probably should default to all. This is somewhat related to next item.
b) Select HSV | S, create a point and increase saturation. Change to RGB (this time defaults to Green), set point to adjust the curve. Now return to HSV | S and the saturation adjustment is gone. Actually, the saturation adjustment is reset when select the RGB space. Adjust HSL|Hue and change to RGB also resets Hue. So can't adjust both? Help seems to hint that only one color space is adjusted. And if that is case, perhaps there should be a warning that change to RGB resets HSL or HSV? Or use check boxes or another control to select color space so that the color space selection is exclusive? User can open a separate color curve transform for each color space.
c) Select RGB | all and set two points at, say x=y=3 and x=y=8 to lock mid range. Change to Expanded histogram. The grid expands with the histogram but the control points do not move. How to set same two points in expanded histogram? Seems to me that the guidelines are just that & should not change if the histogram expands?
Thx,

a) Color curves default to HSV | V color space; Change to RGB and this defaults to Blue. Change to HSL | Hue; change back to RGB and now default is Red. RGB Probably should default to all. This is somewhat related to next item.

b) Select HSV | S, create a point and increase saturation. Change to RGB (this time defaults to Green), set point to adjust the curve. Now return to HSV | S and the saturation adjustment is gone. Actually, the saturation adjustment is reset when select the RGB space. Adjust HSL|Hue and change to RGB also resets Hue. So can't adjust both? Help seems to hint that only one color space is adjusted. And if that is case, perhaps there should be a warning that change to RGB resets HSL or HSV? Or use check boxes or another control to select color space so that the color space selection is exclusive? User can open a separate color curve transform for each color space.

Each color space has 3 channels -- if the 3rd channel is selected in one color space it is also selected in the other. The intent is that you will use one color space which you select first and then adjust the three curves. Switching color spaces resets the curves. I will add this to the help file.

c) Select RGB | all and set two points at, say x=y=3 and x=y=8 to lock mid range. Change to Expanded histogram. The grid expands with the histogram but the control points do not move. How to set same two points in expanded histogram? Seems to me that the guidelines are just that & should not change if the histogram expands?

Expanding the histogram does not affect the curves so the control points stay in the same locations. The point of expanding the histogram is to help you see parts of the histogram that were compressed by a large peak somewhere else. It would not make sense to expand the curve scale as well as this would make it much harder to know what the curve is doing to the image. For example, the main diagonal (lower left to upper right) is critical for knowing if you are lightening or darkening the curve. It would also make it very hard to adjust highlights since they would be highly compressed.