The Preserve Visibility option affects all aspects of image editing.
When Preserve Visibility is selected, pasted selections do not affect
clear areas. Also, a pasted selection will match the transparency of
the existing pixels when you defloat the selection.
You must deselect Preserve Visibility to paint in clear areas of an
image. Then, if you want to edit the painted areas, select Preserve
Visibility again.
For example, you can deselect Preserve Visibility and paint airbrush
strokes in a clear image. Then, select Preserve Visibility and you can
paint over the airbrush strokes to change their color, without losing
the soft edge or spilling color into clear areas.
When Preserve Visibility is selected and you use the Eraser tool, pix-
els you erase are painted with the current background color; they
are not erased to clear.
Also, when you use any painting tool to apply color, you cannot
make pixels more or less transparent. This is why you cannot apply
any color in clear areas when Preserve Visibility is selected.
When you select Preserve Visibility, you can paint and apply filters
to modify pixels that are less than 100% transparent. You can change
the hue, saturation, and intensity of pixels but cant change their
transparency.
To paint or apply filters to an entire image, deselect Preserve Visibil-
ity. This turns off the visibility mask and lets painting tools and filters
affect the entire image.
Tip
If an image is completely
clear (contains no colored
pixels), you cannot alter
the image when Preserve
Visibility is selected.