Hi,

I'm interested in whether adjusting colour channels in Gimp can be used to detect chlorophyll emitted by biological life, or damp patches in roofs and masonry of buildings.

I've been experimenting with this but have found the results to be inconsistent. I've tried things like boosting the green in the green channel and the red in the red channel and also removing all the red and boosting the green in the red channel and removing all the green and boosting the red in the green channel etc.

I don't really understand what I'm doing with this.

Does anybody know whether this is a technique that could work in the diagnoses of damp related issues in buildings?

Any advice greatly appreciated!

Thanks,

I installed Gimp in early January of this year (2026) on a new Chromebook. I use to be able to launch and use it, but it no longer launches. The bar, at the bottom shows it attempting, but fails after a couple of minutes.

Its a new Chromebook. Model Asus CX15.

I had to install Linux first, so it runs under Linux. It no longer works.

I've used Gimp for a while, but only in the most rudimentary way.  I'm now trying something new for me that has me stumped. I've RTFM, searched online and watched YouTube vids, but I must be obtuse.

I have a scan containing two fragments of a document that I want to piece together. I successfully moved the fragments apart and now want to rotate each piece individually. I selected one piece using Tools->Selection Tools->Rectangular Select. Next I activated Tools->Transform Tools->Rotate. In Tool Options, I set Transform: Selection. I'm up to this step in the first screenshot. I enter a rotation, 90 degrees. I get a crawling ants frame that is otherwise all white. When I select Rotate, the blank white crawling ant frame remains. The originally selected region remains unchanged (second screenshot).

I'm sure I'm missing something obvious, but how do I accomplish the rotation I want?

-- Greg

Attached Files

Thumbnail(s)
       

This is with Gimp 3.0.8-2 and Darktable 5.4.1 on Windows 11. When I try to open an ARW raw from my Sony camera or a DNG raw from my Leica, Gimp starts Darktable and the images display in Darktable as I would expect. When I close Darktable it displays "Exporting to GIMP" on the screen, but I then just get an error dialog, and the image doesn't appear in Gimp. 

For ARW files, the error dialog is this:
   

For DNG files, the error dialog is this:
   

When I look at Gimp's preferences for Image import and export, the import options are set to this:
   

Any suggestions on a fix?

Hi there, I am working on extending GIMP with AI functions. I ditched Photoshop lately and my pals at the Photo Club keep telling me that I am a fool to have ditched PS with all it's nice AI functions. They shouldn't say that to me...

At this moment I've got AI Remove Background working, using IOPaint that runs locally on my laptop. It still needs some fine tuning, but it works.

Now I am working on 'inpaint' (filling a selection with a generated background). I am struggling now how to make a mask from a selection. The GIMP API has many procedures, but just copying a selection seems not to be easy. Is there anyone who has some experience with this?


P.S. I am new to Gimp Forum, so maybe I missed earlier questions/discussions like this.

Can we expect to see some of your plugins for gimp 3 anytime soon? I know it says on your site that the path plugins were still only for 2.10.
3 must have a plugin folder if it can support GMIC or does it need something else?

I want to use a different font.  When I select 'text tool' from the left pane, then the tool options pane for text appears in the right.  In the 'Font' field it has a default of 'Sans Serif'.  I can start typing with, for example, 'book' and a pull down list of font names is shown.  I can click on a name, but the font field is not changed.  The text I type does not show the font I want.
 
Likewise, I can drag a rectangle in the body of the image and small toolbox appears above it.  I cannot change the font name here either.  Is there a way to do this?

I am using GIMP 3.08 (revision 1)

I need help on how to apply to a new layer a 3d transform, mapping it to another layer that has an photo of an object. I want to map the 3d object already present in the older layer and apply my new layer on this perspective, like a stencil painted on a surface

I need something like making a path that matches the corners of the 3d object, and then 3d transform the stencil layer upon the object. Take this for instance: I have a phone case, and the the case will be the 3d surface that I want to map. I have another layer that has numbers on it, on a grid of 5x5, where the first line goes from 1 to 5, the second goes from 6 to 10, and so on. I want to be able to put this grid on the screen of the monitor, and adjust what is shown, move it around (following the guide from the mapped perspective) and apply zoom, like showing the top left corner zoomed in (1, 2, 6 and 7) or the center zoomed out (7, 8, 9, 12, 13, 14, 19, 20 21).

In this attached example I tried my best to guess the image correct transformation, but as you could see they are a little distorted.

Thank you very much for your time!

Attached Files

  case.xcf (Size: 879.75 KB / Downloads: 56)

An update from the 2.10 plugin for Gimp 3

https://www.arakne.es/en/gimp-plugin-sha...ator-2025/

All sorts of shapes as paths, there is a demo video on the above

Hi,

Look, please, at the following image:

   

I wish to transform the big black area in transparency (but not the hair of the girl    ), and very important:

• I need to draw the visible areas with my mouse,
  
• I do not wish to work by deleting the areas that are going to become transparent.