Transparent

Create and Erase on a Transparent Layer
This simple illustration applies to all Transparent Layers you may create. Open a new file. Select the Lasso tool and draw an irregular shape (1). Turn this into a floater. Fill the floater with a dark orange color and paint in some lines to add to the shape (2).
Normally when you create a Transparent Layer it automatically becomes the same size as your painting background. To create a Transparent Layer the same size as an existing floater (2), select it, then select Floater/Transparent Layer in the Objects:Floater List palette. You now have a Transparent Layer the same size as your floater. The selection marquee defines the total area of any floater or Transparent Layer.
In the example below (3) I filled the T-Layer with Black ( it defaults with White as the color). In the Brush: palette I chose the Airbrush tool, with a Feather Tip variant. Next I chose Plug-in for the Method and Transparent Layer Brush as the Subcategory. Then I painted the interior with flames and let a diagonal line run from one corner to another to show the total area of the T-Layer

To erase the diagonal line, I select the Transparent Layer in the Objects:Floater List. Next, I click on the Mask icon to open the Objects:Mask List, and select Transparent Layer Mask (the bar will turn blue). If I open the EYE I see a Black & White version of the mask (4). I can erase the lines in either mode. It is not necessary to switch to the eraser or any other tool to do this. But…It is necessary to change the Method to anything but Plug-in or Wet. I chose 100% White (removes & Black adds to) as the Primary Color in the Art Materials palette and painted over the lines to remove them.

I want to add a few curly vines. I can paint only in the current mask, which is behind the pumpkin. I could paint here but I won’t have much control over what I am doing. In order to accomplish what I want to do, I must switch back to Plug-in for the Method and Transparent Layer Brush as the Subcategory and re-select the Transparent Layer in the Objects:Floater List. Now I can see the vines in color as I add them to the Transparent Layer. Add a few strokes to create the illusion of depth and you’re finished. Try applying some lights. It is amazing what can be done with a few clicks of a button