Hi Steve -

In flipping between the various tabs on the layers and channels dialog I have found it's really easy to be looking at one thing and editing another. When you want to edit a channel, make sure (a), that that channel is both visible and selected s the active channel; ditto for the layer mask, or the layer itself. You need to select the proper thing in the layers and channels dialog, and then move back to the image window to do your actual modifying with the drawing tools. You might want to make sure, too, that you aren't trying to work outside an active selection, or that you don't have "preserve transparency" turned on. Also, make sure that the color you're using to draw with isn't the same as the background of the channel you're trying to draw into. (/me speaks from experience).

HTH,

I started using the Gimp a few months ago and struggled with this at first, too. I'll see if I can help. To see how altering a selection with a channel mask, follow these steps. 1. Open an image and make a selection. 2. Right click in the image and do Select/Save to Channel 3. Make sure your layers dialog box is open (C-l) and click on the channels tab to see your channel mask selection. 4. Toggle on the eye to activate the mask. The selection will still be there.
5. Remove the selection (the dotted lines) with C-S-a and you have the mask remaining.
6. Double click on the bar with Selection Mask copy, you can name the channel mask and set a color by double clicking on the black box. Opacity setting of about 50 works well. 7. Now you're ready to alter your mask. Select the paintbrush tool, to add to the mask, make sure the foreground color is black. To subtract from the mask, switch the foreground color to white. 8. For this to work, be sure the layer that's active is the selection mask layer in the channels area and the eye on the left of the bar is toggled on.
9. When you have the changes made you want, right click back on the layers dialog box and click Channel to Selection. The Selection with the moving ants will return.

This is a start for learning how the "painting" with masks works.

A simpler demonstation can be seen by clicking on the small red box at the lower left of the image window. Make sure you have a selection. The mask will be red. It can be altered with the paintbrush tool by adding to the mask with the foreground black and subtracting with the foreground white.

Hope this helps.

Judy Wilson

* Steve Crane [020709 17:22]:

I have recently been making an effort to learn as much about using the GIMP as I can. I have been referring to the GIMP User Manual, Grokking The GIMP and several tutorials that I have downloaded. These all suggest that I should be able to use the painting tools to modify layer masks and selection masks saved in channels. However these tools have absolutely no effect and I'm wondering if there is something I am not doing that is needed to be able to do this. I am using version 1.2.3, built from source, and am running it on SuSE Linux 7.2.