[Gimp-user] Masking for Contrast Control - Can this be done in Gimp?

[David Gowers]

On Wed, Apr 1, 2009 at 6:32 PM, paperaussie <paperaussie at gmx.net> wrote:
>
> Can any experienced Gimp users tell me how the process described in Ron
> Bigelow's article can be reproduced in Gimp most efficiently?
>
> http://www.ronbigelow.com/articles/contrast/contrast.htm
> http://www.ronbigelow.com/articles/contrast/contrast.htm
>
> Looks like a quite handy process to optimise some photos. I think I sort of
> could reproduce it with layers but I couldn't figure out if it is possible
> to follow these instructions with channels.

The procedure in GIMP is virtually identical. I'll paste the most
relevant part here, adjusted for GIMP:

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A selection of the entire image is created by choosing Select/All. The
image is now copied by choosing Edit/Copy. A new channel is created by
clicking on the Create new channel icon at the bottom of the Channels
dockable (see Figure 5). The channel should be renamed the Contrast
channel. The image is now pasted into the Contrast channel by
selecting that channel and choosing Edit/Paste, going to the Layers
dockable and clicking the Anchor icon. Next, it is necessary to invert
the black and white image by choosing Colors/Invert.

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