Many folks don’t understand how valuable selections and masking are for working on their digital photos. It’s true that compositing is an important use of masking, but that isn’t the only or even the primary use of selections and masks. I’m entirely a fine- art photographer these days, and I frequently use masks to improve my photographs.
Masks are way of exercising local control over a photograph. They let you control what parts of an image get affected by your manipulations. A mask is nothing more than a grayscale image that has the same dimensions as the photograph you’re working on. Black areas in a mask completely block whatever change you’re making to the photograph; white areas permit the change to work at 100% strength. Gray values in the mask produce intermediate- strength changes—the lighter the tone in the mask, the stronger the effect of your manipulation on the photograph. Masks can even modulate filters and adjustment layers in Photoshop.
Sometimes a mask is simple and contiguous, like the backdrop behind a product. Other times it can be complicated and non-contiguous, like pieces of sky seen between branches and foliage in a landscape. In some cases, I want to select for a particular characteristic, like tone or color. Or I may select all the highlights or shadows in a photograph so that I can adjust their appearance without altering the rest of the photograph. Sometimes a mask is amorphous and ill-defined, like the tarnish in an old photograph. (Check online at photo-repair.com/DRBook Promo/DR_Excerpt3.htm for instruction on how remove the bluish sheet of tarnish from black-and-white photographs using a mask.)
Using masks isn’t hard. The big trick is creating a good one in the first place. Building a perfect mask by hand, pixel by pixel, is time-consuming and tedious. Third-party tools can do very sophisticated masking with fewer clicks of the mouse and strokes of the stylus, saving hours of work on a single photograph.
One such tool is Fluid Mask 3 from Vertus (www.vertustech.com/fm_over view.htm), a $239 program for both PCs and Macs. It runs under Windows XP SP2 or Vista and Mac OS X 10.3.9, 10.4.9, or later. You can run it as a stand-alone program or as a Photoshop plug-in under Photoshop CS2 or CS3. It’s a universal Mac application, running on both Power PC and Intel processor machines.