I thought for a while when first reading your post that he was using alpha channel adjustments. Having now seen the video it seems he has just gone and altered the view to grayscale. Click on Image - Mode - Grayscale (this is just a viewing mode while working on the file), and change it back when done with the adjustments. Working in a grayscale is much easier as it's easier to see the adjustments without being distracted by the colors and colorfringing and such.
I have CS 6, but the same should apply. Also, be sure to shoot in Raw, as it gives you more flexibility in pulling on curves and levels afterwards.
Hi, thanks for your post. My problem is in CS2 if I have the color tiff on my PS desktop and click image-mode-grayscales, PS asks me: "Do you want to discard the color data?" And then as far as I can see it gets iretrievable afterwards...hmmm.
@MrBean: Thanks a lot! I will do so. Did several like that before, always like touch the limits ;- at least photography wise...
Hmmm.. Seems you are right. I have never used this, but gotten a grey picture when sharpening in alpha layers, so I thought it was retriveable. It probably is, I just don't know how to do it. There are however many people in this forum who are experts on photoshop.
Below is a picture (actually eight taken with the 16-35 II, and stiched) I took some weeks ago in Shanghai. Below that is the same picture converted to grayscale, the one I was not able to revert.. I'd be interested in seeing how to solve this