New colour adjustment tools question.

[Susan S.]

Richard - thanks for the new tools. The channel mixer adjustment layer and the selective colour adjustment layer are new to me - do you have any suggestions as to how and when they would be useful? Perhaps if anyone has a reference to a decent on line photoshop tutorial on these tools - I'm particularly interested in comparisons of the advantages and disadvantages of the different colour manipulation tools.
Susan S.

[Richard_Lynch]

Susan,

I guess my rather cold answer to this is: if I thought these tools were as good as those I already included with the Hidden Power CD, I'd have included them. Don't get me wrong, they are good tools, but I don't find them particularly more useful than stuff you will already have. However, some ideas:

Some people like to use the Channel Mixer to convert images to black-and-white. This would be done by checking the Monochrome box and adjusting the sliders. The other thing you could possibly use it for is in color correction to mix channels. For example, if you separated an image into RGB w/Preview, and then thought you could use, say, the red channel to kill some jaundice in a subject by adjusting the blue channel with the red, this gives you the opportunity to do so without the additional setup. There is a section on Channel mixing in Hidden Power, if you have a look there, it shows the kind of color change that is possible. Personally I find the channel mixer dialogue a little more confucing than a physical application of layers.

Selective color provides some of the utility of what I show how to do with Hue/Saturation. It gives you pre-defined color ranges that you can affect using sliders. For example, say you looked at your image and felt the mid-range grays were a little, oh, Magenta. You could open a Selective color adjustment, choose neutrals from the drop list and shift the Magenta slider to the left to drop its influence in that range.

These are quite powerful tools, and these are but a few quick examples of what you can do. In combination with other tools (I am thinking Blend Masks), you can probably take care of a bunch of selective color changes.

I'd be interested in looking at other ways to apply these in combination and separately. If anyone knows where there are tutorials, please post links here!

[Susan S.]

Thanks Richard - I'd found a couple of things by googling, on the channel mixer - for doing black and white images from colour it is pretty quick and useful. Unfortunately I neglected to bookmark them so I can't give a reference (oops - but my photoshoop favorites list is so big that I tend not to add to it when I can help!)- I gather that there are presets around that you can load up to simulate various B&W photography filters which might be quite handy, but I haven't got round to locating any yet. I used to do a bit of black and white film photography, but never set up my own darkroom - this little tool gives a lot of the same control that using different filters over the lens gives and wastes a lot less chemicals and paper! As I like monochrome images this is a really useful add-on.

(I must confess I still haven't finished working throught the section of the book on channel mixing. I'll get there, I promise, but I'm such a gadget freak I've been having too much fun playing with the actions - and even taking some photographs!).

As far as I can see I agree that selective colour adjustment doesn't seem to add anything to what the use of Hue/saturation does - and as that is PE native it has the advantage that you can go back and tweak the adjustment layer later.
Susan S.