Photoshop

To use the Equalize command

The Equalize command redistributes the brightness values of the pixels in an image so that they more evenly represent the entire range of brightness levels. Equalize remaps pixel values in the composite image so that the brightest value represents white, the darkest value represents black, and intermediate values are evenly distributed throughout the grayscale.

You can use the Equalize command when a scanned image appears darker than the original and you want to balance the values to produce a lighter image. Using Equalize together with the Histogram palette lets you see before-and-after brightness comparisons.

  1. (Optional) Select an area of the image to equalize.
  2. Choose Image > Adjustments > Equalize.
  3. If you selected an area of the image, select what to equalize in the dialog box, and click OK:
    Equalize Selected Area Only
    Evenly distributes only the selection’s pixels.

    Equalize Entire Image Based On Selected Area
    Evenly distributes all image pixels based on those in the selection.