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> Screen-grabs can be taken in JPG JPEG is unacceptable for screenshots of text, unless you can disable chroma subsampling, which isn't always an exposed optio

> Screen-grabs can be taken in JPG JPEG is unacceptable for screenshots of text, unless you can disable chroma subsampling, which isn't always an exposed option. As a quick test, I took a screenshot of this comment, and saved it as both a PNG and 100% quality 444 JPEG, exported from GIMP. The JPEG is 81477 bytes, and the PNG is 44212.

ttoinou 3y ago
Note that sometimes text is not rendered as 1D monochromatic but with some kind of slight pixel-level chromatic abberation. In this case I'm not sure PNG will do so well
- Retr0id 3y ago
  In my test the screenshot had no subpixel AA, but if it did why would that be an issue? (beyond it looking ugly when upscaled)
  - epcoa 3y ago
    It would make the compression take a (tiny) hit. In your test case being dominated by a solid color patch (which describes many screen shots), it would make no practical difference.
tecleandor 3y ago
I was surprised and confused about this, specially because I take certain care on the screenshots I paste on technical docs everyday, using PNG and a quantizer to reduce color depth. But on second read I think we're making a mistake because we work on a different domain. I think the article exclusively refers to images produced I'm the workflow of video/CGI/3D rendering and generation for the motion films/multimedia industry. And there it can probably make sense to use a format like that, same as when I use a DNG or similar for storage of my photos. I think when he said "screen-grab" he wasn't referring to an screenshot of a computer app or desktop, but to a frame of a video or something similar.
- Retr0id 3y ago
  They are primarily talking about VFX workflows, but they make it quite clear that their opinions of PNG extend to all other use cases too
out_of_protocol 3y ago
took random screenshot with text. original - ~200kB png. oxiPNG - ~107kB. Browser Jpeg - 604kB, MozJPEG 100 - 538kB, MozJPEG 100 RGB - 669kB. JpegXL lossless - 26kB. AVIF lossless max effort - 306kB

ttoinou 3y ago

Note that sometimes text is not rendered as 1D monochromatic but with some kind of slight pixel-level chromatic abberation. In this case I'm not sure PNG will do so well

Retr0id 3y ago
In my test the screenshot had no subpixel AA, but if it did why would that be an issue? (beyond it looking ugly when upscaled)
- epcoa 3y ago
  It would make the compression take a (tiny) hit. In your test case being dominated by a solid color patch (which describes many screen shots), it would make no practical difference.

tecleandor 3y ago

I was surprised and confused about this, specially because I take certain care on the screenshots I paste on technical docs everyday, using PNG and a quantizer to reduce color depth. But on second read I think we're making a mistake because we work on a different domain. I think the article exclusively refers to images produced I'm the workflow of video/CGI/3D rendering and generation for the motion films/multimedia industry. And there it can probably make sense to use a format like that, same as when I use a DNG or similar for storage of my photos. I think when he said "screen-grab" he wasn't referring to an screenshot of a computer app or desktop, but to a frame of a video or something similar.

Retr0id 3y ago
They are primarily talking about VFX workflows, but they make it quite clear that their opinions of PNG extend to all other use cases too

out_of_protocol 3y ago

took random screenshot with text. original - ~200kB png. oxiPNG - ~107kB. Browser Jpeg - 604kB, MozJPEG 100 - 538kB, MozJPEG 100 RGB - 669kB. JpegXL lossless - 26kB. AVIF lossless max effort - 306kB