Colorize a Black-and-White Image in Photoshop CS5
You can use blending modes in Adobe Photoshop Creative Suites 5 to tint a black-and-white (grayscale) image with color. You can’t paint color in Grayscale mode, so follow these steps to use blending modes to add color to a black-and-white image:
Open an image in any color mode and choose Image→Mode→RGB.
If the image isn’t already a grayscale image, choose Image→Adjustments→Desaturate.
This feature makes it appear as though the image is black-and-white, but you’re still in a color mode and can apply color.
Choose a painting tool (the Brush tool, for example) and, from the Swatches panel, choose the first color you want to paint with.
On the Options bar, select Color from the Mode drop-down list and then use the Opacity slider to change the opacity to 50 percent.
You can also just type 5.
Color Blending mode is used to change the color of pixels while keeping intact the underlying grayscale (shading).
Another way to bring attention to a certain item in an RGB image (such as those cute greeting cards that have the single rose in color and everything else in black and white) is to select the item you want to bring attention to.
Choose Select→Modify→Feather to soften the selection a bit (5 pixels is a good number to enter in the Feather Radius text field). Then choose Select→Inverse. With everything else selected, choose Image→Adjustments→Desaturate. Everything else in the image looks black and white, except for the original item you selected.