PNG "Apply Gamma correction" in Import options does nothing?

[Roger Breton]

I tried changing the default 1.0 value to any other number and it does not seem to make a difference in the overall appearance of the imported image. I wonder it this option actually "works". 

[rob day]

Hi @Roger Breton , It’s working for me once the file is placed:

[James Gifford—NitroPress]

How do you get the import options to show up after you've placed the image?

[rob day]

You have to load a PNG–tested in CC2021, haven’t checked CC2024.

The PNG Image Import Options Preview doesn’t respond to the Gamma number, but the link does

[James Gifford—NitroPress]

Yes, I've loaded a PNG, with Import Options checked (multiple times for this). I don't understand your comment above about "once the file is placed" — when I place any image through the Import Options panel, the latter disappears when the placement is complete. Nothing I can do while the operation is in progress changes the PNG in any way, which is what I assume Roger is seeing as well.

[rob day]

Not sure I understand the scale—can’t imagine using it for a color correction.

[James Gifford—NitroPress]

I see you asked this a while back and got no answer.

I've just spent 20 minutes messing around, and came up with only one conclusion, which I'll reserve for the moment. The short answer is that no, this option and collateral setting seem to do nothing at all with any PNG graphic I have at hand (Win 11, v19.4).

Furthermore, I am mystified as to what it's supposed to do:

Adjust the mid-tone values? Okay. Import a gamma value from the PNG? Okay. It doesn't seem to do any of these, and I am unable to find any useful information on PNG gamma mucking-about, in Photoshop help or anywhere else. (I'm not the strongest color-technology mind in here, but I do grasp it at a photogrraphy and print-prep level... and I am fairly mystified by all of the above, especially the lack of explanation and the lack of any apparent effect.)

Hence that conclusion: PNG is a format I avoid at all costs except when I need web transparency with something too large for a GIF. 🙂

[Roger Breton]

Thanks James. I can't figure the gist of this option. Perhaps, I thought, as I read the same documentation you show that, perhaps, when a PNG is save with "some" gamma, other than the 'standard' value (whatever that is), InDesign picks up on it and allow the user to change the value on import? Totally hypothetic... although I find "interesting", from a color management viewpoint, the idea of being able to, say, import the same image multiple times and assign different gamma values each time? In principle, that would be a useful thing. But as you noted, something is amiss...
BTW, I find I'm pretty much saving most graphic files in PNG to import in InDesign or simply as a base storage format, these days. I still use JPEG on larger files though. I like the idea that PNG isn't "lossy" as JPEG.