Friday, 26 March 2010


This is just a test shot for posting on a forum showing problems I'm having with a feathered brush used on a mask layer. This has been exaggerated to enable viewers to see the problem easily.

On Gimp if I duplicate the background layer, then alter the new layer on curves for example, then add a mask layer and use a large feathered brush at any opacity with zero hardness on the brush, it does reveal the layer below where used but leaves these concentric circles. Obviously the more the brush is used the more anomalies that are left behind. Although not very noticeable at low magnification they are still there and would probably show up on prints I assume. Does anyone know what if anything am I doing wrong as this could be effecting a large proportion of my work. Also it is more noticeable on B&W work than on colour.


donnie said...

sorry - have never used a layer in my life

Mark Alan Meader said...

If you're only talking about a layer mask, I doubt you would see any banding in the finished product.
I'm not familiar with GIMP so I don't know what options you have, but check the bit-depth.. going to 16 or 32 (if possible) may help if you are working at 8.
Try adding a bit of gaussian blur to the mask.. that should smooth it out. Banding in gradients is an OLD problem.

Mook said...

Donnie all the more kudos to you sir!

Mook said...

Mark cheers I just found out today it is the bit depth that's the problem, gimp only has 8. Basically I've been doing the Craig Tanner big brush mask layer thing.

I haven't come across the adding a gaussian blur to the mask so I'll give it a try, but much as I don't want to I might have to go the Photoshop way :(

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