Page 411 - Xara Designer Pro X17

The Photo Tools 411

By dragging the white eye-dropper from the Levels dialog over the whitest part of the
image, it not only restores a better overall histogram, but also corrects the blue cast so
that the white snow really is white.

The corrected histogram now shows a much better balance (it's largely at the white end,
but that's to be expected in a snow scene).

Auto Levels
The AUTO button will automatically adjust the white and black points to correspond to the
lightest and darkest shades in the selected picture. This works better for some images
than others (the above snow scene works perfectly, so in fact this can be corrected with
a single click).

Reset
The "RESET" button will reset all levels parameters back to their starting values. The
"COMPARE" button on the Photo Tool's InfoBar also does the same thing, but has the
advantage that pressing it again restores the altered settings.

Advanced Levels - The Green Line
For the more advanced user, the levels control is really mapping the range of input
brightness levels to an alternative set of output levels. Overlaid on the red histogram is a
green line that represents the mapping function.

The default straight line means no change, so dark shades are mapped to dark, and light
to the same light shades. But as you alter the controls the green line is altered to reflect