Tom,
two things:
1) Any way to see a side by side of before/after, or even just to see the history of the before?
2) I wish I could paint an area, select brightness, and then move the brightness slider to see how it applies it to the mask in real time. It seems the only way to do it is to select the brightness you want FIRST ??
Not sure about the first item, but I just figured out how to do the second one, which is pretty cool! Here's an example:
1. Start with a fresh image and choose a filter (Brightness/Contrast).
2. Use the slider to make a very noticeable difference. You'll change the amount later, you just want your paint area to be noticeable.
3. Choose the paintbrush, and on the next screen choose the paintbrush again.
4. Paint the area that you want to change, and click the OK checkmark.
5. Tap the Layers tab. Now, you'll see on the side bar an icon of your image, and an icon of the mask under the heading of the Filter you used.
6. Tap the icon of your image to Edit Image.
7. Now, you'll see all the available Filters again on the side bar. Again, choose Brightness/Contrast.
8. Now, when you slide the slider, you're changing the Brightness/Contrast in the Mask area like you wanted.
Another thing you can do when you're in the Layers tab, is tap on the icon above the Edit Image icon (the icon looks like 3 little sliders). A side bar will pop up with a lot of choices I have no idea about, except the top one, which is "Duplicate Layer". This will duplicate the mask that you made, and allow you to add a different effect in the exact same area.
FYI - I think I may have uncovered a bit of buggy behavior when applying a second effect with an existing mask. I went to blur an area that I had already changed Brightness/Contrast, and as I was adjusting the Blur amount, the image started to look goofy, with a big black area appearing. When I clicked "OK", everything looked fine again, with the Blur applied.
Regards
Tom