Quoting Victor Domingos <[EMAIL PROTECTED]>:

> Is there a preference in GIMP, to make a channel appear as a
> grayscale layer, instead of a red, green, or blue layer? Is
> decomposing the image the only way to do this? I would laike to
> compare two channels more easily, and the R/G/B color cast doesn't
> seem to help...

There is not really such an option built-in to the GIMP. If your main  
concern is just comparing the channels then you could create a layer  
from them rather easily by dragging the component (R,G, or B) from its  
position at top of the Channels dialog to the bottom, then dragging  
the resulting new channel over to your image window. You can drag a  
component directly to your image window, but realize that the  
components displayed in the Channels dialog will then be based on new  
layer; so in order to do this for the next channel, you would need to  
hide the layer.

You might find a script I wrote a while back to be useful  
(http://flashingtwelve.brickfilms.com/GIMP/Scripts/decompose.scm). It  
decomposes a layer to its constituent components and uses those as  
layermasks to red-, green-, and blue-filled layers. It doesn't handle  
the alpha channel in the original layer (doing so would introduce some  
inherent difficulties that are worse than having the limitation).

Once you have decomposed your layer using the script, you can edit the  
layermasks of the respective channels -- viewing either the resulting  
projection or using "Show layermask" to view the grayscale version of  
the respective channel (I would recommend assigning a quickkey to the  
Show Layermask function, as it is handy to switch between the two  
views). To restore the original layer, just make only the four layers  
(R, G, B, and black) visible, assure that none of them are showing its  
layermask, and do a Merge Visible.

Gimp-user mailing list

Reply via email to