brush not contained to my alpha 1 mask selection please help

[Guest]

Hi, 

Attmepting lumiosity masks...I select and save the blue channel as new channel. Put a curve on the alpha 1 channel. Back to layers, create a black mask, reselect alpha 1, start painting using brush. It is my understanding that the brush should be contained to the area that is selected ( illustrated by marching ants) but the brush will paint anywhere.

Colour is white. Mode is normal.

Can't seem to find this issue in a forum anywhere or figure out the solution. Please help. THanks!

[Norman Sanders]

Try this. It takes far, far longer to describe step-by-step than to do. 

1. Before making the Blue Alpha Channel, add a mask to the appropriate layer in the Layers panel.

2. Move to the Channels panel and create the Blue Alpha Channel.

3. Select > All followed by Edit > Copy

4. Click on the RGB to choose RGB, and R, G and B channels. Then return to the Layers panel

5. Choose the mask and then Option click on the mask. The screen will go white. You have chosen the mask.  

6. Edit > Paste. It puts the Blue Channel Alpha in the mask.

7. Deselect the marching ants and then make the selection you have in mind

8. Paint in white with a hard edged Brush 

9. Click on the eye to see the result and deselect the marching ants

Note: You can do Step 9 before Step 7 but be sure to paint on the mask

Good luck.

[josephlavine]

Is your Alpha channel solid black and white? Keep in mind that the selection (marching ants) only shows the area that is more than 50% selected. Thus, areas that are gray on the mask are actually part of the selection even though they do not show up inside the selection.

I hope that helps.

warmly/j