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Displays Any way to screenshot in Full RGB colour space?

Discussion in 'Hardware' started by boiled_elephant, 12 Nov 2019.

  1. boiled_elephant

    boiled_elephant Merom Celeron 4 lyfe

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    This has flummoxed me. My graphics card is outputting 8-bit full RGB. My screen supports the same. I can visually verify that I have the full 0-255 range visible. But when I screenshot in Windows or with the snipping tool, the result is colour compressed and shows 0-235.

    (Clarification edit: the image below isn't one of my screenshots. I've included one further down for comparison. This is an original untouched RGB Full sampler from a web search.)

    leveltest.png

    It's not RGB Limited as I understand it, because in the screenshots I can still distinguish 0 and 16. But 255 becomes 235.

    Any way around this? It affects game screenshots in Steam too.
     
    Last edited: 12 Nov 2019
  2. edzieba

    edzieba Virtual Realist

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    That screenshot looks full-range to me (25 and 235 are distinct shades, as are 0 and 16).
     
  3. GeorgeK

    GeorgeK Swinging the banhammer Super Moderator

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    Same here - I can see 4 distinct stripes
     
  4. Gareth Halfacree

    Gareth Halfacree WIIGII! Staff Administrator Super Moderator Moderator

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    Here, too, on a calibrated but very cheap Philips VA panel. All four stripes are extremely distinct.
     
  5. GeorgeStorm

    GeorgeStorm Aggressive PC Builder

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    Seeing 4 stripes at work both on laptop and monitor, very clear 235-255, 0-16 is less so.
     
  6. Gareth Halfacree

    Gareth Halfacree WIIGII! Staff Administrator Super Moderator Moderator

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    You don't have a monitor colour profile applied, do you? I know that when I calibrated my monitor I got *really* confused, because I'd told The GIMP to use the colour profile and when I copied an image from Firefox and pasted it into The GIMP it looked completely different - turns out that I had to also tell Firefox to apply the profile to all images, not just those tagged as colour-corrected.

    Could something like that be at play? You're viewing the original image in something which is applying the correct colour profile so you can see all the lines clearly, but when you copy and paste it it's going into something which doesn't apply the correct colour profile. That'd explain why we can see the lines fine: they're still in the image.

    In fact, that should be the case anyway: doesn't matter what the GPU is outputting or the monitor is displaying, the screenshot should capture the image as it actually is in video memory (except, I guess, if your GPU is dithering, maybe? Dunno about that one.)
     
  7. boiled_elephant

    boiled_elephant Merom Celeron 4 lyfe

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    Here's what a screenshot pasted straight into Irfanview looks like:

    screenshot_2019-11-12.jpg

    I'm baffled because everything I can find online about screenshot methods in Windows implies the same thing you guys are saying - that it directly captures what the GPU is outputting. The GPU is outputting 8-bit RGB Full to an 8-bit RGB Full compatible screen. Yet screenshots are experiencing some sort of heavy colour range compression - and only in the upper end, not in the blacks.

    Oh but to add to the confusion, the screenshots in Steam Overlay do mush up the blacks. 0 on this scale in Elite Dangerous comes out as 16.
     
  8. Gareth Halfacree

    Gareth Halfacree WIIGII! Staff Administrator Super Moderator Moderator

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    I can confirm there's no difference between 255 and 235 in that one. I don't mean "no discernable difference," I mean "no difference:" they're both #FFFFFF.

    What happens if you try to take a screenshot using something like The GIMP, or Firefox's screenshot facility? Equally, what happens when you paste a screenshot into something other than Irfanview? Is there a difference between a screenshot saved directly as PNG and one pasted into an application first?
     
  9. yuusou

    yuusou Well-Known Member

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    Try going oldskool, PrtScr, paste into Paint, save as BMP.
     
  10. wyx087

    wyx087 Homeworld 3 is happening!!

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    Do you see 4 stripes on your browser?

    I noticed my default Firefox browser wasn't displaying my photos correctly, after export from Lightroom into photo gallery server program. Turns out, there's a switch in Firefox use monitor colour profiles.

    I've experienced Steam screenshot showing strange colour dithering for game screenshots. But never PrtScr on a window, always captures exactly what I see.
     
  11. boiled_elephant

    boiled_elephant Merom Celeron 4 lyfe

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    Sorry for the necro, lads, I got so busy with work over winter I forgot all about this.

    It's still a thing. I'm using a GTX 1070 and a Samsung 55" TV, which is running in HDR. I'm guessing the HDR and the TV are something to do with it.

    The colours aren't compressed on the display output. The screenshot method and output application don't matter - snipping cool, prnt-scrn, steam overlay, paint, irfanview. They all do it. What you see in that compressed screenshot is not what I see on the display; the on-screen image is fine, full range.

    Drivers are the latest Nvidia ones. Connector type is HDMI, cable is a good un.

    It's not a high priority but it still baffles me, and I still can't take screenshots without them compressing like this. I suppose the next thing would be to try a different display.

    Edit - I'm tired-dumb, it can't be the display, can it? That's not how screen capture works. It must happen somewhere between the operating system and the API. The 1070 isn't faulty, or I'd see problems on the display.
     

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