The Extra-Strength Tips for the Clients and Friends of Ben Willmore (www.digitalmastery.com):

With our heads still swirling with thoughts of color, we're going to expand on the ideas I taught you in the last tip, so if you didn't read that one, be sure to visit www.digitalmastery.com/tips and catch up with the tip from 12/19/04 before continuing.

Last time around, I showed you a basic concept for how many of Photoshop color adjustments can work. The main idea was that the Info palette can show you which general colors you'll shift your image towards when you are adjusting Red, Green or Blue in the Curves dialog box (although the same thing applies to Levels). Now, let's see how the numbers that show up in the Info palette can help us figure out how to shift the color of an image towards a specific color.

Go find two images that include people and open them in Photoshop. Make sure that skin tones in the photos look different. Maybe one includes a tan person and the other includes someone who has pale white skin (although try not to mix races, otherwise you'll be starting with a rather difficult adjustment instead of one that's appropriate for this tip). We're going to end up shifting the color of the first person's skin so that it looks similar to the second person's skin. Before moving on, arrange the two photos so you can see both of them at the same time and choose Window>Info to make the Info palette visible.

With the photo you want to shift active, make a selection of part of the skin using the Marquee tool. The selection does not have to be accurate, it's just there so we don't shift the entire image. With that selection still active, choose Layer>New Adjustment Layer>Curves. Now, remember back to the previous installment of my Extra-Strength Tips... Remember that you could Command-click (Mac), or Ctrl-click (Win) to add a dot to the curve? Well, for this image, we want to add a dot to each of the Red, Green and Blue curves. To accomplish that, hold the Command-key (Mac), or Ctrl key (Win) to indicate that you want to add a dot, then add the Shift key (which indicates that Photoshop should add a dot to all three of the R, G and B curves) and click within the skin of the image you want to change. It won't look like anything happened, but if you change the menu at the top of the Curves dialog box, you should find a dot on each of the Red, Green and Blue curves. Now let's see how we can use those dots to precisely shift the color of the skin.

While you're still in the Curves dialog box, release the keys you were holding down, move your mouse over the second image and click in an area that has a similar brightness as the first image. With the mouse button still held down, look at the RGB numbers that appear in the Info palette and write them down. Those numbers indicate the exact formula that Photoshop uses to make the color of skin your mouse was over. Now, back in the Curves dialog box, set the Channel pop-up menu at the top of the Curves dialog box to Red and then change the number that appears in the Output field at the bottom of the dialog box to the first number you wrote down from the Info palette. Next, change the pop-up menu to Green and change the Output number to the second number you wrote down. Repeat this process with the menu set to Blue and use the third number you wrote down. The image will look rather weird until you get all three numbers entered into the respective Red, Green and Blue output fields. Once you have them entered, the area of skin the first photo should be close to matching the color of the skin in the second.

Before you click OK in the Curves dialog box, cycle through the Red, Green and Blue curves once more time and look at their overall shape. If any of them have what I call I "hard landing" (where the curve suddenly bottoms out), then click within the flat area of the curve and drag the resulting dot close to the dot you added earlier until the shape of the curve looks nice and smooth.

Finally, click Ok in the Curves dialog box to apply the adjustment and then choose the Paintbrush tool. With the newly created Adjustment Layer active in your Layers palette, paint with white on any area of the skin that didn't change color, or paint with black on any non-skin areas that shifted but shouldn't have.

This tip has only covered about 4% of what you'd learn if you'd either read the Color Manipulation chapter in my Photoshop CS Studio Techniques book or watch my Mastering Color DVD. If you're interested in expanding your knowledge of color, then visit www.digitalmastery.com for info on my books and DVD's.

Or if you'd rather learn about a wider variety of Photoshop techniques, check out my new on-line class at http://www.betterphoto.com/photocourses/BEN01.asp

-Ben Willmore