How do I create a gradient map from an image?

If I have an image that I know started off as greyscale and that somebody has colourized it with a gradient map, and that the resultant image is sufficiently detailed to have all 256 lightness values mapped to a colour -- then how do I create a colour gradient map from that image so that I can colourize images similarly myself?

I know that this is possible because I did it myself a few years back and I have the .ggr gradient maps that resulted, but Google has failed me now and I've forgotten how I did it.

Hello,


do you know if it is possible to script funciton:

colors - desaturate - color to grey?

I didn t find it

as well as: colors- Color temerature


Thanks for your help

        I need to remove the lines from the following image. It was recommended that I use threshold. When I tried that, it removed some of them, but not all of them. In addition, it turned it black and white. Is there anything else that can be done?

Hi everyone. I downloaded GIMP a week ago. I want to make a thumbnail for my YouTube video, where 3 pictures of 1920*1080 resolution are put in three equal parts in a 1920*1080 picture. I want them to be divided by three slashes (/) rather than a straight line. Thanks!

Hey all, I'm having a bit of trouble here.  A few days ago, Windows 10 decided to do an automatic update, and ever since then Gimp crashes on startup, specifically when updating the tag cache. 

Here's the exact error message.



Currently I'm using gimp 2.8.22, however when the problem first started happening I was using a slightly older version.  I had uninstalled and reinstalled gimp several times, attempting to solve the problem.  

I don't have any brushes or plugins installed, and I only had one font installed, although I probably don't anymore, since I had deleted every file on my computer with the name Gimp attached to it.

This problem is frustrating to say the least, and I'd greatly appreciate any help.  Thanks!

Can someone to explain how to use with the plugin?

[img=1000x750]https://i.imgur.com/InhjxY9.jpg[/img]Check it!

Howdy GIMP folks,

My daughter (12) is working on becoming an artist. I just purchased here a Huion G10T drawing pad based on some online reviews, and trying to make a smart investment in case she doesn't end up following through.

We've got her set up with GIMP, and everything was working fine last night. At some point however, the tablet started changing tools ever time she tries to draw with the stylus. Primarily the pencil that I'm aware of. Google isn't providing anything helpful, and I'm failing to figure out what's happening.

Does anyone have any experience with this glitch? Or should I just go deep dive with reinstalling everything and learning how to use it myself for trouble shooting?

Thanks!

I can't figure out how to change the brush size. On another website it shows a picture of the slider under the title of the brush but on my screen there's no slider. Where is the slider supposed to be?

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Dear Forum,

I need to halve the resolution of about sixty .png pictures, from 600dpi to 300dpi, preserving their Alpha Channel (transparent background).

I tried with XnView, which provides a very complete batch conversion/editing tool, but, ulnluckily, in the new 300dpi files Alpha is suppressed.

What can I do?

Can GIMP work on these several files this way, with a unique batch action?

Thank you.