I am a new GIMP user with a quick question. I am using "Add Layer Mask" and the radial gradient tool to create a transparent hole in a png layer. The radial gradient tool only applies maximum transparency at the cursor vector center fading to opacity at the end of the cursor vector. Is there a way set complete transparency over a circular region fading from complete transparency at the circle edge to the end of the cursor vector?
Just make a circle selection and bucket-fill it with black, leaving the rest of the mask white.
Explanation: the layer is opaque where the layer mask is white and transparent where the mask is black. Achieving complete transparency of the layer over a circular area is done by painting a black circle on a white mask, and painting a black circle is done by making a circle selection and bucket-filling it with black.
I'm adapting the answer to the OP's level of expertise as demonstraded by the question. We don't want to copy the whole Gimp manual each time, do we?– xenoidNov 8, 2016 at 13:09
Thank you for the suggestion and explanation, xenoid. As an alternative, I found that editing the gradient profile is also helpful in increasing the size of the transparent hole generated with a radial gradient. I did this by adding a new palette with the palette dialog, adding 3 or more colors with the "new color from foreground" button, transferring the palette to a gradient using the "palette to gradient" operation, and editing the new gradient from a button in the tool options window. Nov 8, 2016 at 21:19
Yes but you'll always have blurry edges that way... But then there is even faster technique, use the Brightess-Contrast tool on the mask, and add contrast to reduce the width of the semi-transparent transition.– xenoidNov 8, 2016 at 21:53