Tip for quickly selecting contrasting colours?

Question

Hello,
I have a custom brush defined of my signature that I put on my photos. As I want the signature to be subtle so it doesn't detract from the photo, I use a colour that almost blends with the colours in that corner of the photo. The signature is visible, yet it doesn't attract attention.
As examples, the signature would be a shade of green over grass, blue over ocean, grey over asphalt, etc.
Selecting the color to use is trial-and-error, tweaking it several times so it isn't too bright, too dark, or too contrasting with the background. As each photo needs a different colour, this becomes time consuming after hundreds of images.
Is there a tool or other way in PS (either CS2 or CS4) to select a colour like this more quickly? Perhaps one that picks an "average" colour from the area for the signature, and then tunes it a bit brighter or darker so it will show up?
At the moment I an experimenting with using the Eye Dropper, set to 101x101 sample averaging (the largest available). So with the signature brush selected, I Alt-click to get this average colour. But then I still need to make the colour lighter or darker, otherwise the signature blends in too well, almost invisible. Is their a shortcut key way to lighten or darken the selected foreground colour?
Thanks,
KDJ

Answer 1

Thanks all!
I hoped changing the brush or layer blends modes alone might do it. On more-or-less gradual background tones, it sometimes works okay. However on busier backgrounds (like grass!), the signature becomes very speckled as almost each pixel takes on a different colour. Unfortunately the effect makes the sig simultaneously both very conspicuous and impossible to read :D
Ho, interesting tool, though not sure how it fits in within PS to select colour based on one area of the image.
J Maloney, I tried following your steps, though not sure I understand what you meant. For "select thay layer trans", unpainted areas of my layers are transparent by default. Do you mean set Opacity to 0%? Or select the transparent areas of the layer, by ctrl-click the layer icon and then Invert Selection? And what do I select for your second Copy Merged? And why two Copy Merges? Can the blending be set on the first layer instead, and skip one?
The Blur Average step might help with the pixelation mentioned above.
I can see this is going to take some experimenting to make fire-and-forget-automated..., variables such as the starting colour, blend type, etc., need to be robust enough so that a single setting works for all images.
Thanks,
KDJ