Originally Posted by R_Fredrick_Smith
The exposure slider sets the white point for the photo. The shadows slider sets the black point. You would normally set these two first before playing with color balance. The easiest way to use them is hold down the Alt key while using the Exposure and Shadows slider. When you first slide the exposure slider the image will turn totally black (or maybe not). If it is black then nothing is being clipped at this point. Start sliding left till something non black starts to display. This will be something white or lighter in the image. What ever shows up will now be pure white in the image no matter what color it is. So back off till there is no white and you now have the optimum exposure. On the other hand, say you're shooting on a white background and you want it pure white, then you could slide until you see details of the subject start to appear, then backoff leaving the subject black. The white point is now set. Now repeat with the Shadow slider except move right slightly. If everything is white, then move back left until something starts to show up. What every shows up will be the darkest part of the photo. You are now choosing the point that you want black, so keep sliding till whatever you want to be the black point can be seen. Ultimately these two steps take a little practice but essentially the same thing you do with the set black and white points while setting up curves.
Now adjust the brightness and contrast sliders which primarily deals with the midtones. Now adjust the white balance.
The Auto settings are usally based on what camera you use. You can calibrate anyway you want using the last tab in CS2 where you make adjustments depending on what you want as your default Auto position. Myself, I just turn Auto off and always go thru the slider sequence above.
CS3 adds several more sliders and tabs including a highlight recovery slider, a fill slider, etc.
Just remember that Exposure/Shadows control the white and black points (the highlight and shadow details and brightness controls the midtones.)
Thank you for your excellent detailed reply. I was hoping you would see my post and respond.
As I worked through your directions, I found in both cases I was moving to the right.
Exposure: Hit Alt, black screen, move to the right, until something lights up.
Shadows: Hit Alt, screen nearly all white, move to the right until black items in the shot show up as being black.
I understand your comments about brightness and contrast affecting the midtones.
Another follow-up question for you: When you are using the Photovision target, do you use the color samplers on the white and black strips? And if so, what values do you strive for?
On my example--
White: R:247, G:247, B:248 (seems good)
Black: R:65, G:63, B:63 (perhaps a bit bright?)
The black seems a bit bright. But if I increase the shadows, then I clip some of the darker areas, such as the perimeter of the target which is a deeper black.
I greatly appreciate your response.