User guide
Image Adjustments and Effects 53
Lens Filter adjusts the color balance for warming or cooling down your
photos. It digitally mimics the placement of a filter on the front of your
camera lens.
Threshold creates a monochromatic (black and white) rendering. You can
set the threshold, i.e. the lightness or gray value above which colors are
inverted.
Equalize evenly distributes the lightness levels between existing bottom
(darkest) and top (lightest) values.
Negative Image inverts the colors, giving the effect of a photographic
negative.
Black and White Film is used for grayscale conversion with controllable
source channel input.
Posterize produces a special effect by reducing the image to a limited
number of colors.
Instead of the manual tonal adjustments above, the PhotoPlus Image menu
affords a number of functions you can apply to correct shadow/highlight values
in an image automatically. Adjust>AutoLevels or Adjust>AutoContrast may
do the job in one go; if not, you can use Adjust>Levels... or
Adjust>Shadow/Highlight/Midtone....
Use the Histogram tab to display statistics and image color values,
helping you to evaluate the kinds of image adjustments that may be
needed.