In my last TidBITS article I wrote that the main reason I use Photoshop is to run Asiva's plug-ins, especially Shift+Gain. Last year Asiva shut up shop, leaving these products unavailable, but they have been purchased by their original developer, who is marketing them again. He is also now, at long last, providing demo versions, making it possible for people to try the products before committing any money. In addition, he has cut their prices and renamed three of the plug-ins to clarify their functions. Here is the line-up. The set of four costs $99.
Current Name Former Name Price
Correct Color Shift+Gain $39
Replace or Apply Correct+Apply $39
Sharpen or Blur Sharpen+Soften $39
Selection Selection $29
These plug-ins allow you to select tones and manipulate them based on their hue, saturation and intensity. Hue, saturation and intensity approximate the perceptual dimensions that the brain works with, so manipulating tones with Asiva's plug-ins is more straightforward than manipulating tones in conventional ways that are analogues of film or are based on the computer's channels of red, green and blue. Asiva's plug-ins enable direct, vector adjustments that would normally require handwork and/or complex masking. Asiva's approach is patented, so these are the only products of their kind.
I use Correct Color for almost every photo, in lieu of all of Photoshop's colour-correcting tools (for details, see "Editing Photographs for the Perfectionist," 2004-09-27, and "Reality and Digital Pictures," 2005-12-12). Replace or Apply is the simplest way I know of to change the colour of a sky or of a discordant piece of clothing or background. Selection lets me select skies and other smooth tones so that I can remove noise only from those areas and retain detail elsewhere. Sharpen or Blur I use occasionally for softening bright elements in portraits.
These plug-ins are available for any version of Photoshop back to 5.5, for any kind of Macintosh or for Windows. The Macintosh demos are universal binaries that will work on an Intel- or PowerPC-based Mac, but they require Adobe Creative Suite 3 and Mac OS X 10.4.8 or later.