Because the Saul Goode LM script is not working in GIMP 2.10.14, Tim Tran created a new script for me. My idea was that the channels should not overlap so that they could be used separately or in combination.

To show my ingratitude, I then modified it (because I had a clear example of Python that I could understand)!
I added a DDDD and LLLL which affect only the very darkest and lightest parts of an image. I also split the M into a medium dark (MD) and medium light (ML).
It allows one to make extreme adjustments using Colours/Curves or Brightness & Contrast without affecting adjacent areas.
Also, by making "loose" selections, one can adjust the required area without changing other parts which may be included within the selection.

I have attached both versions. Tim's is named david_lum_mask.py and my modification david1_lum_mask.py
(Linux users will have to make them executable.)

I hope others will try both versions and give comments and criticism.

david.

Yet another update!
Because luminosity masks can be unusable for low-contrast images (one mask can contain almost all of the picture content), I have modified my previous script.
It now equalizes the layer used to create the masks. The full range of masks are now available for use on low-contrast images.
This avoids the need to produce time-consuming hand drawn masks.

It does not appear to have any negative consequences for photographs of normal contrast.

Linux users will have to make the file executable.

I would appreciate feedback as to its effectiveness.

david.

David, thanks for your work. I've been trying to make use of layer masks for some time now, following them from the initial essay description to the first scripting of the procedure and the several scripts since then. How to handle especially the middle values has been unsettled from the very beginning. The number of masks created has varied, as well as where to locate the masks in the GIMP work area and how or if to assign modes and visibility. I was glad to have all of the variations because creating such scripts in either scheme or python remains out of my ken.

I can't comment on the technical aspects of the scripts, but, speaking as a user I believe your "ungrateful David" version was the first "complete" version of what was originally attempted. It seemed to work better, was faster, and offered more genuinely usable mask layers than what had come before. (Sometimes script writers left out layers altogether and other times cautioned users that some of them just weren't very useful.) Upon finding your take on the script, I began archiving all the previous versions I had collected and used from time to time.

In my opinion, your update, applying EQ to the initial stages, could point a way for even further creative development. I would be very interested to see where this additional processing approach might lead.

So, just in case you were beginning to wonder ...

Thanks again!

I have version 2 installed. How do I call it up to use the plugin?

mackenzieh,

You should find the script under Python-Fu/David2 Luminosity Masks... Click on this and it should create all the layers and masks.

neurolurker,

I am glad you find it useful. I used the Saul Goode script for several years. When it ceased to work under GIMP 2.10 I decided to incorporate ideas I had thought about for a long time. Although it is not ideal I hope it proves useful to you.

david.

David,

Here is what I see when I load up gimp:




I am running gimp 2.10.14 on Windows 10 64bit. I don't see your plugin.

EDIT:
I now have your plugin.

mackenzieh,

One of your screen captures is showing it under Python-Fu - David2 Luminosity Masks...
If you click on it, having loaded an image, it should run.

Close to midnight here in the UK. Let me know how you get on and I will look for your reply in the morning.

david.

Necroposting, but, updated version that works with 3.2.4:


And a version that just makes channels instead of making image layers (my preference):


These were bot-updated, but I read through and it looks good (and works well, so far at least).