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+--- Thread: Editing photos (/Thread-Editing-photos)
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Editing photos - gazza - 05-31-2023
Hi
I have been taking quite a few landscape photos recently and editing them in GIMP. When the photos are taken the hills or mountains in the background just appear dark outlines. I understand the naked eye would just see them as dark outlines depending on how far away they are. I believe in Lightroom and Photoshop, an adjustment brush can be used to brush over those items to lighten the dark contrast and make the colours of those hills etc more visible. What would be the best method in GIMP. I am assuming that maybe I have to select the areas and adjust the contrast and brightness. I have tried that but the results are not wonderful
Any help appreciated
Gary
RE: editing photos - Ofnuts - 05-31-2023
The good technique is to use a "luminosity mask". This makes for very progressive touch up. There is the canonical tutorial by PatDavid that explains the principle very well.
In action it looks like this:
Starting with this image where the shadows along the quay are a bit too dark:
[attachment=9878]
You create a luminosity mask that extracts the very dark pixels (DDD using PatDavid's conventions)
[attachment=9881]
and apply Curves (Brightness-Contrast isn't very good at the ends of the histogram).
[attachment=9880]
[attachment=9879]
As you can see the effect is applied in full on the quay walls, but the shadows in the roofs have also become a bit lighter. Of course it is also a matter of subtlety, you have to be careful to not overdo it. In particular if you use such a mask to boost the dark parts, color shifts occur very fast because a minute difference between two color channels is expanded by the increase of values.
You can use the method expounded in the tutorial to create the masks, but I also have a script with some pre-cooked ones and you can create your own (or use part of the script just to extract a luminosity channel).
RE: Editing photos - gazza - 06-04-2023
Thank you Ofnuts
It took a while, but I did get the luminosity masks working. The changes are very subtle, and I can see that you don't need to over cook any of the settings. Obviously it also depends on what photos are being altered as to how much difference it makes. I will continue with this over the coming weeks and no doubt get better at the adjusting.
Regards
Gary
RE: Editing photos - gazza - 06-09-2023
Hi again
I have been experimenting with this process, but what I have found is the when I try to change the Darker areas, the mask method does not work as well as selecting the "Shadow" adjustment which is in Gimp. I seem to get more changes when I choose the Light masks. In fact, to be honest, I find that a number of the standard built in parameters in Gimp seem to make more of a difference than the mask method. Am I expecting too much change from using this method?
Thanks
Gary
RE: Editing photos - Ofnuts - 06-09-2023
For small adjustments I would agree with you, but the tool is also prone to generating halos if you push the sliders.
Luminosity masks are of more general use.
RE: Editing photos - PixLab - 06-10-2023
(05-31-2023, 08:38 PM)gazza Wrote: Hi
I believe in Lightroom and Photoshop, an adjustment brush can be used to brush over those items to lighten the dark contrast and make the colours of those hills etc more visible.
Any help appreciated
Gary
You are searching for the Dodge and Burn tool
https://docs.gimp.org/en/gimp-tool-dodge-burn.html > " The Dodge or Burn tool uses the current brush to lighten or darken the colors in your image. The mode will determine ... "
[attachment=9908]
RE: Editing photos - gazza - 06-14-2023
I would like to send some more issues to do with these threads and would like to send a word document attachment 16.9kb and another jpg of 19.6kb. When I attach them to the post, it only shows one being attached. Can I only send one at a time.
Regards
RE: Editing photos - PixLab - 06-15-2023
(06-14-2023, 10:29 PM)gazza Wrote: I would like to send some more issues to do with these threads and would like to send a word document attachment 16.9kb and another jpg of 19.6kb. When I attach them to the post, it only shows one being attached. Can I only send one at a time.
Regards
zip them together, the forum accept the compressed archive .zip and .7z then upload them to the forum > https://www.gimp-forum.net/misc.php?action=help&hid=11
RE: Editing photos - Ofnuts - 06-15-2023
(06-14-2023, 10:29 PM)gazza Wrote: I would like to send some more issues to do with these threads and would like to send a word document attachment 16.9kb and another jpg of 19.6kb. When I attach them to the post, it only shows one being attached. Can I only send one at a time.
Regards
You can have up to 5 attachments, but the accepted types are mostly images types (.png,.jpg,.xcf...) or archive/compressed types (.zip, .7z, .gz).
If you aren't using one of the allowed type you get this message:
[attachment=9933]
So upload your Jpeg as an image and put the .doc in a ZIP file.
RE: Editing photos - gazza - 06-16-2023
Hi Again
I have been endeavouring to use this method and when I first started had some excellent results and was able to change brightness and contrast along with removing shadows. However, for some reason now, I cannot for the life of me get it working. I created a “Cheat Sheet” of instruction in the form of a word document (attached) which did work and still works in as much as I seem to be able to create the masks per the instruction. You will notice on the .jpg file attached the Dark to Darker and Bright to Brighter mask look like they are correct. However, when I go to implement any changes, nothing happens. I have tried a number of photos in which I wanted to decrease the amount of shadow for example but nothing changes.
Could there be an issue with my Gimp. I have 2.8 and 2.10 installed but neither of them will change any Brightness, Contrast, using Curves, Levels, etc etc.
However, if I open any image make any changes that one would normally i.e. without following the Luminosity method, all of the above tools work perfectly i.e. Brightness, Contrast, using Curves, Levels, etc etc.
Regards.