Hello,

My hobby is astrophotography and what I cannot do with Siril in linear image or in PixInsight LE in non-linear image I do it with GIMP.

I would like to ask you a question regarding several closely related processes.

I work with raw format that I convert to TIF. In photographs with a high dynamic range, and assuming there has been no loss of information in lights and shadows, it is necessary to increase light in shadows and reduce light in highlights, and then increase local contrast. In GIMP with the G'MIC plug-in I find several processes that I can use. If I use masks I can use them on certain areas and if I break up the image with wavelets
I will be able to use them only on certain structures (stars or nebula).

In relation to the dynamic range of the image:
1. Colors > Exposure (exposure for me is a combination of aperture, ISO and exposure time, but this process has two sliders for shadow level and 'exposure'). There is a tutorial to bring up the shadows, but what about the highlights?
2. Colors > Shadows/highlights
3. Colors > Brightness/contrast
4. Colors > Auto > Equalize
My doubt with these is because I think that they are several perspectives of the same thing: the modification of the black point, the white point, and the midtones in the histogram; and I have no information on whether they cut out the information or not. Is there any other tool that will help improve the dynamic range of this
type of images?
Regarding the dynamic range, and trying to be clearer, I am looking for a tool that allows me to increase the space of the shadows and the highlights, at the expense of a compression of the midtones, so that I can extract detail from the extremes of hystogram (and this is not only to move three points in the hystogram I suppose)

And to increase the local contrast:
1. Filters > G'MIC > Details > Local contrast enhancement
2. Filters > G'MIC > Details > Tone mapping
Are they the same? From a technical point of view, could someone tell me what each of these processes does?

Have hundreds of old slides to scan in, and unfortunately, the majority of them seem to be Kodak Ektachrome, and have a red/brown tinge to them.
Is there a good tutorial around, or an "easy fix" to correct this? (He says, hopefully...)
Sample:     

I've managed to load an editable set of lines. I now want to draw a precision circle and I'm stuck again

Hi, longtime Gimp user, 10+ years, very casually though.

The SSD where Gimp was installed recently died (Christmas). Today, I tried to install Gimp on a different drive and the installation fails. It is trying to install Gimp on the no longer existent drive, and there is no option to install it on the new drive.

Before you tell me to "uninstall the old Gimp" as per the pinned instructions on this forum, Windows uninstaller fails, of course, because the old SSD does not exist. The old SSD is dead.

Therefore, since the Gimp installer lacks such a basic function as drive selection, it appears I will need to spend time in the registry. I am not a computer genius, so yay. Great design choice.

So could someone with a bigger brain than me please explain step by step how to remove the old Gimp from the registry so that the Gimp installer can then install to the correct drive?

Thank you.

Hi-

This dog was standing on a red mat and you can see some of the red reflected on their white hair. I have removed all the extraneous parts of the image but would like to change the color or tint of the edges. 

If I used the fuzzy select tool to select these red areas how can I change those areas to more closely match the surrounding areas that are more white?

thx!

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when i run the mouse over the photo that i have showing nothing happens...when i turn to black then it rubs the photo out and shows the patern in behind the photo.
Should the white have any affect on the photo or am i missing something?. hope this is clear.

hi ,
I am using gimp 2.10 on windows 10
I want to do the following
Select a polygon section in an image . I am able to do that using free select tool .
Now I want to select any vertex of polygon and pull it farther . This should distort the image inside that polygon . But when I do that simply the polygon shape changes but there is no effect on underlying image .
I hope that I am able to explain my requirement .
To give another example - suppose image is of human body . I draw a polygon such that right hand is inside it , now when I will stretch or squeeze the polygon then right hand should get deformed . 
Can you tell me how to do above ?
Thanks.

I am trying to load a set of generated 2 point lines on top of the image they display a hidden geometry to..
I have stuck path-csv-0.1.py in my plug-ins directory and it shows up in the plug in browser.
I cant find where it is in the interface, how to run it.

Hello, 
I'm new into Gimp but think that i will use it for long time,
pretty exited by extension opportunities 

the first thing that i want to do is have an extension that permit to add a Qr code on my pictures 
with some option like embed a logo or not,
set the color of the Qr code.

The only way that i have to done it is go on a dedicated website like (https://www.qr-code-generator.com/ ) 
download the result and then import it into my image. 

When i tried to look on internet that's what i found for the moment : 
- https://www.youtube.com/watch?v=YHXX3KuB23Q ( presentation from Akkana Peck  about basis to write a gimp plugin )
- https://www.gimp-forum.net/ (this website but the thread about Qr code dont discuss the possibility to build an embeded one / but very happy to join a community around gimp )
- https://github.com/isman7/gimp-qrcode (this repository on github, i did'nt understand all yet )

If the subject talk to someone i will very happy to exchange about, cause i think that can be useful in the process of making flyers , reciept, branded bag ( like the one i'm working on - see pic )

Have a good day ^^

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I have an image that has to be used with a de-saturation shader.  Normally I just up the saturation so the colors are not washed out, but said image already has several colors that are at maximum saturation.  Is there any way to compensate for the de-saturation?