Masks - Can't seem to get it right

[AceMcHammer]

I'm running GIMP 2.10.20 on Windows 10 on a 4K screen.

I searched for and found various GIMP mask tutorials but for some reason it never comes out right.  

I have a specific image that I'm trying to "enhance" with a mask.  BTW, this image is a copyright released image found here for any would-be copyright nazis out there.

I'm trying to get this image here.......




to look like this image here.........




As you can see the second image has a very light sort of sepia tint to it and I'm guessing they made a mask over the whole image.  So if I like the second image better then why don't I just use the second image?  I have a higher resolution image of this image than the one that I found online that's been masked and in addition to that the second image has been cropped and I want to use the uncropped image.  

Can someone give me detailed instruction on how to get the first image to look exactly like the second image by making a mask?  Thanks in advance

[Ofnuts]

You don't need a "mask" (or at least not the "mask" concept as understood in Gimp). .There are plenty of tools to shift colors slightly.

* Colors > Color temperature an increase the intended temperature slightly (this is a prime candidate if you have two image that are likely two photos of the same source, but taken with a slightly different white balance)
* Colors > Hue chroma and slightly reduce the hue
* Colors > Hue saturation

The ultimate tool for this is a CLUT, using the GMIC plugin. Using the before and after images it will produce a Color Look-Up Table (CLUT) that maps the colors between the two images. With the same plugin you can re-apply the CLUT to a different image to obtain the same result (in theory, in practice you can only apply it to a similar image, a CLUT created using an image with plenty of reds may not give good results on an image with plenty of blues.

[rich2005]

Looks like you might get it with an HDR effect.  There are plugins around for Gimp 2.10 but pure Gimp

Try: Colors -> Tone Mapping -> Mantiuk2006 with settings as shown:

   

It is not a very fast effect, so for a large image, be patient.

[rich2005]

Another one that might be of interest.  There are two effects Dragan and Dave Hill, if you search there are methods for these.

Using Gimp 2.10 a very old plugin, (attached) Put it in your plugins folder. Find it on the menu bar - PythonFu. Unusual in that it gives advice as it runs and it does use masks. Edit: playing around, sometimes the "advice" dialogues pop-under the main Gimp window - just as long as you know. For a trial just run through to the end and on the top layer adjust color/hue-chroma

   

[AceMcHammer]

(08-10-2025, 05:34 PM)Ofnuts Wrote: You don't need a "mask" (or at least not the "mask" concept as understood in Gimp). .There are plenty of tools to shift colors slightly.

* Colors > Color temperature an increase the intended temperature slightly (this is a prime candidate if you have two image that are likely two photos of the same source, but taken with a slightly different white balance)
* Colors > Hue chroma and slightly reduce the hue
* Colors > Hue saturation

The ultimate tool for this is a CLUT, using the GMIC plugin. Using the before and after images it will produce a Color Look-Up Table (CLUT) that maps the colors between the two images. With the same plugin you can re-apply the CLUT to a different image to obtain the same result (in theory, in practice you can only apply it to a similar image, a CLUT created using an image with plenty of reds  may not give good results on an image with plenty of blues.

I know the Color Temperature adjustment well and use it often to make images look warmer or cooler but the color temp alone will not create the effect of that "sepia" mask or of that slight brownish mask.  

I actually tried to duplicate the effect using all my usual adjustments of Hue Saturation, Color Temp, Brightness Contrast, Chroma, Color Balance, Exposure (black level), Curves and this is what I came up with without a mask.....



..which looks pretty close but it's still not like the other image.  I had to go to Hue Saturation and adjust the "Hue" of the red, yellow and magenta I believe mostly get it to look like that.  I basically concentrated on matching the color of the sail masts.  But in the other image I can tell by the lines in the sails look darker and the also the color of the water that it's probably a mask.  Even the water has that slight sepia tint.  I can bring out the lines in the sails a bit more with contrast but then brighter areas start to loose detail.  And that's another reason I think it's a mask in the other image because the of the darker lines in the sails without overexposure of bright areas.

I do have the GMIC plugin but have not tried the CLUT option.

---

(08-10-2025, 05:48 PM)rich2005 Wrote: Looks like you might get it with an HDR effect.  There are plugins around for Gimp 2.10 but pure Gimp

Try: Colors -> Tone Mapping -> Mantiuk2006 with settings as shown:



It is not a very fast effect, so for a large image, be patient.

Trying to set the contrast and saturation adjustments that you showed with the dialogue of that effect froze my computer up 

(08-10-2025, 07:33 PM)rich2005 Wrote: Another one that might be of interest.  There are two effects Dragan and Dave Hill, if you search there are methods for these.

Using Gimp 2.10 a very old plugin, (attached) Put it in your plugins folder. Find it on the menu bar - PythonFu.  Unusual in that it gives advice as it runs and it does use masks.  Edit: playing around, sometimes the "advice" dialogues pop-under the main Gimp window - just as long as you know.  For a trial just run through to the end and on the top layer adjust color/hue-chroma

I'll give that a try too.

[rich2005]

(08-10-2025, 09:21 PM)AceMcHammer Wrote:

Quote:Try: Colors -> Tone Mapping -> Mantiuk2006 with settings as shown:
It is not a very fast effect, so for a large image, be patient.

Trying to set the contrast and saturation adjustments that you showed with the dialogue of that effect froze my computer up 

It might be your old version (2.10.20 ??) and Windows, but GEGL real-time rendering on large images is very intensive. If you want to give yourself an example use Colors -> Desarurate -> Color to Grey on your large image and you see GEGL rendering block-by-block

For your large ship image turn the preview off - wait for that to become active - then it is easier to enter the parameters.

example: https://i.imgur.com/M8v6Pgh.mp4

...or of course your computer might just run out of steam.

[denzjos]

You can try this :
Make a copy from the original layer
Colours / Desaturate / Sepia
Set layer mode : Burn
Set layer opacity 20 pc
You can finetune with : Colours / Curves
   

[AceMcHammer]

(Yesterday, 11:55 AM)denzjos Wrote: You can try this :
Make a copy from the original layer
Colours / Desaturate / Sepia
Set layer mode : Burn
Set layer opacity 20 pc
You can finetune with : Colours / Curves

Sounds like a good idea.  Will try

[sallyanne]

Or you could try
Duplicateing your image and set it to muliply layer mode at 50%