Digital Light & Color

Is there any way to add up opacity in masks with multiple strokes with a transparent brush? When I tested Photoshop Elements this was possible, and I think it's very useful.

Having the mask paint tool be cumulative with multiple clicks would be extremely useful. The paint tool and clone tool both work that way -- only the mask paint tool does not.

This may not be strictly OT for this thread but the following techniques may be what you would ultimately be doing with an accumulating Mask Tool - Add/Subtract Paint Brush capability [possibly making Technique (3) easier]...

...The following three dodge-burn painting techniques are currently possible with PWP4 or later:

(1) Composite-Softlight/Paint Tool - soft-sided White/Grey/Black Brushes of specific tones and varying tranparencies;
(2) Composite-Softlight/Misc Tools - soft-sided midtone mode Lighten/Darken Brushes [accumulating using multiple strokes or clicks and varying tranparency]; and
(3) Composite-Softlight/Mask Tool - soft-sided Add/Subtract Brushes of varying transparencies on an initial 50% gray solid tone 'active' mask.

The workflow setups are similar for all three techniques and Technique (3) is described in detail here:
http://www.dl-c.com/discus/messages/2/1 ... 1207209217

These techniques take a bit of practice and depend heavily upon one's artistic recognition of photo-realistic lighting and painting ability of an image's main visual elements.