Basically equalization means that you take a look at the overall impression of the image (its histogram) and accordingly change the values of the pixels so that there is an equal distribution of values across the entire range. For example, if a greyscale image is predominantly mid-grey with no highlights and deep shadows, equalizing it will change the image so that there is an equal amount of shadows, midtones and highlights. It is obvious that this in its simplicity is a crude operation that can both ruin or improve a picture, but this can be avoided by only equalizing to a certain degree, by only equalizing luminance and by applying Power Retouch’s special Photographic Mode.
This Photoshop plug-in lets you equalize luminance to varying degrees. Use our special Photographic Mode to integrate the equalization into the photo. Or use a graduated effect.This is the Equalize Luminance Photoshop plug-in's control panel. Click on the image for a larger view.It works with the following image modes:8 & 16 bit/channel: RGB, CMYK, Grayscale, Duotone, Lab.
70%, Photographic mode
70%, not Photo mode
Photographic mode integrates the retouch nicely into the original image as you can see from the following three flower images. Far more nuances and shades are preserved when Photographic mode is on. The result is not so dramatic, but it is aesthetically far more pleasing in most cases. Photographic mode is not available for greyscale images and does not make any difference in B/W RGB images.
50%, not Photographic mode
Enlivening a dull photo
As you can see from the photos to the right, slight equalization of luminance will raise contrast without altering the color values and add more life to an otherwise nice, but dull, photo.
These three sliders let you adjust the amount of filtering in the lights, midtones and darks.The photo to the right was filtered with midtones at max. and lights and darks at 0. Photographic mode was off.Note how much more life and variety comes into the face. Models photographed in the shade are rather dull and flat. Midtone targeted equalization of luminance will help this.
100%. Midtones only.
60%, darks only
Here we only filtered the darks to get the most details visible in the dark shop. Photo mode off.
Often you do not want to equalize a photo uniformly but only in one side or in a corner.In this instance we do not want to equalize the sky but only the lower right corner.We equalized 50% and did not use Photographic mode.