Quote:..Many colleague of mine work with TIFF files, in which (opening them with some apps like Photoshop) you can find several layers (brightness, shades, paints etc.).
I was really hoping for one of those TIFF files, AFAIK PS does not support multi-layer tif, of course files can be added as layers and adjusted.
From your screenshot https://ibb.co/KsVZd2V I can make a PS .psd (albeit an ancient PS7) with text and adjustment layers. My screenshot: https://i.imgur.com/0UY5jm5.jpg
You can see that the dark green patch has been 'adjusted' to a lighter green by those 'adjustment' layers.
Opening that .psd in Gimp (2.10.22) I get this: https://i.imgur.com/0dsjlEV.jpg Problems with PS .psd files
1. Text layers are rasterized, no longer adjustable as text.
2. Adjustment layers are discarded. Gimp does not use 'adjustment' layers. That puts the green layer back to its original hue.
3. Layer masks are saved, which might be useful.
Not much you can do about that, PS and .psd are propriety formats and change depending on version of PS used.
What can you do with that psd ? Using command line ImageMagick (IM) you get some information about the various layers, and extract individual layers. Here I pulled out the 5 layers identified by IM as individual parts. https://i.imgur.com/fxNtGTO.jpg
Open-As-layers in Gimp gives this https://i.imgur.com/fSRgdmW.jpg Not a lot of use, since the layer offsets are lost and all the layers are centered. Green layer is dark green.
However there is a flattened layer there. Layer 0 which has positions and adjusted color. https://i.imgur.com/WKkZM0T.jpg
It would be possible to re-construct the original from that but a big job if there are dozens of layers. Then export as a mult-layer tif.
Best I can do with the information available.