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Hi all.

tl;dr

Photo edits don't have the desired results. Probably because when I import photos into Gimp, the brightness, contrast, saturation (etc.) change subtly but perceptibly. I think this is due to Color / Colour Profiles(?) What am I doing wrong, and how can I get more predictable results? Thank you in advance.

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Apologies for what feel like pretty "noob" questions. (And further apologies if they've been answered 1,000 times already; I searched the forum, but maybe my search fu is lacking).

The problem: 

I take photos with my smartphone, then import the jpegs into Gimp for post-processing. But they look different in Gimp - flatter, greyer, less bold - than they do in the File Browser (Finder; I'm using macOS on a MacBook pro). I think this is due to the Colo(u)r Profile: Finder says "Colour profile: sRGB IEC61966-2.1" but AFAICT Gimp is using sRGB(?)

I've experimented with Image > Colour Management > Assign Colour Profile... and Convert Colour Profile... ...but I can't discern any difference, so I assume I'm using them wrong.

Q1. Am I right in my assumption: is the Colour Profile the problem?
Q2. I want the changes I make in Gimp to accurately reflect what I'll see in Finder; what's the best way to achieve this?

Bonus question (...possibly opening a can of worms?): if my ultimate goal is to post the results online, does it matter which colour profile I use...?

Any help gratefully received  

P.S. macOS, Gimp 2.10

sRGB comes under many names but is is always the same.

Edit>Preferences>Color management: is the managed color display enabled?

Also, assuming that the Apple finder displays the photos without any enhancements could be incorrect...

As Ofnuts says, how do you know that it is not the image viewer application causing a change.

Just for info,  there is no appreciable difference between the embedded Gimp sRGB and the Industry standard sRGB IEC61966-2.1 extracted these with exiftool.

[attachment=5719]

If you are worried about it, turn color management off in Edit -> Preferences.

(03-11-2021, 12:46 PM)Ofnuts Wrote: [ -> ]sRGB comes under many names but is is always the same.

I think Elle Stone would disagree with that statement: https://ninedegreesbelow.com/photography...rison.html

Hi all, and thank you very much for responding; I appreciate it.

Quote:Also, assuming that the Apple finder displays the photos without any enhancements could be incorrect...

@Ofnuts: Well, quite. And I am definitely not assuming this!  But there's clearly something different between the way Finder parses the image file, and the way Gimp does - whether that's a configuration difference / mismatch or something else - because the same images look different in the two of them. I'm trying to understand why, so I can get more predictable results.

To give you an example: I wanted to enhance an image by boosting the contrast and saturation slightly (a simple task for Gimp, given all the amazing tools it has). And I was able to get what I wanted pretty quickly...but when I exported it from Gimp and compared it to the original, I discovered that the latter actually looked better (better contrast, better saturation) in Finder  When I went back to Gimp, I realised that the original layer (the un-processed and un-edited image imported directly into Gimp) looked different from the way it looked in Finder. Which is when I started to wonder about Colour Profiles...

Quote:If you are worried about it, turn color management off in Edit -> Preferences

@rich2005: I'm not worried: I'm trying to get results that are reliable, repeatable, predictable.

Quote:I think Elle Stone would disagree with that statement: https://ninedegreesbelow.com/photography...rison.html

@Kevin: That's such a good site: lots of great information, and conveyed very clearly. Nice pictures, too. I think the author is very generous with their time and knowledge  

Thanks again to all.

(03-11-2021, 04:08 PM)mister_marbles Wrote: [ -> ]

Quote:If you are worried about it, turn color management off in Edit -> Preferences

@rich2005: I'm not worried: I'm trying to get results that are reliable, repeatable, predictable.

Then you need to color calibrate your computer display. This comment a reverse of yours, a PS user complaining that the image does not look the same in a mac.
https://community.adobe.com/t5/photoshop...-p/9557293

(03-11-2021, 06:03 PM)rich2005 Wrote: [ -> ]

(03-11-2021, 04:08 PM)mister_marbles Wrote: [ -> ]

Quote:If you are worried about it, turn color management off in Edit -> Preferences

@rich2005: I'm not worried: I'm trying to get results that are reliable, repeatable, predictable.

Then you need to color calibrate your computer display. This comment a reverse of yours, a PS user complaining that the image does not look the same in a mac.
https://community.adobe.com/t5/photoshop...-p/9557293

(?)

Are you sure? I followed the link...but that's for a different issue. The problem there is that images look different on different devices; my problem is that images look different on the same device - the same screen - but different applications (Gimp, and Finder).

Forgive me - perhaps I'm missing something - but if I (re)calibrate the screen then surely that will affect everything i.e. all applications, including Gimp and Finder(?)

How will (re)calibrating the screen affect disparities between applications...?

I use linux, no 'Apple-anything' so no comment on the hardware, however from that article about viewing in different applications

Quote:If the monitor is not close to sRGB, such as wide gamut units, this won't work. Then you must have full color management.

and a look at mac monitor calibration https://photographylife.com/how-to-calib...ac-monitor

Do you have one of those wide-gamut displays ? Do you have a monitor profile ie. 'something.icm' to feed into the Gimp color management settings?

Try asking the question on https://discuss.pixls.us/ more chance there of someone with comparable hardware.

...packing in for the night, so bye...