Luminous Landscape Forum

Raw & Post Processing, Printing => Digital Image Processing => Topic started by: Dennis on June 29, 2006, 06:15:08 am

Title: color subsampling w/ JPEG
Post by: Dennis on June 29, 2006, 06:15:08 am
I once heard, that Photoshop starts with color subsampling when pulling the quality slider to a value smaller than 7. I think, that was with version 7. Is it still that way with CS2?
Title: color subsampling w/ JPEG
Post by: John Sheehy on June 29, 2006, 08:37:27 am
Quote
I once heard, that Photoshop starts with color subsampling when pulling the quality slider to a value smaller than 7. I think, that was with version 7. Is it still that way with CS2?
[a href=\"index.php?act=findpost&pid=69413\"][{POST_SNAPBACK}][/a]

While you're waiting for an answer, make a bitmap that is fine patterns of color, like a 1-pixel checkerboard of red and blue pixels, and save with the preview box checked, and look to see where the colors disappear, and you get magenta.
Title: color subsampling w/ JPEG
Post by: Dennis on June 29, 2006, 11:17:14 am
Quote
While you're waiting for an answer, make a bitmap that is fine patterns of color, like a 1-pixel checkerboard of red and blue pixels, and save with the preview box checked, and look to see where the colors disappear, and you get magenta.
Yes, I know, but I am so lazy today, so I thought I just ask. Anyway, I did it - and got almost blind watching a blue and red checkerboard at 1600%  

Color subsampling starts with Photoshop CS2 using

 - "Save as" with the slider at 6 or lower

 - "Save for Web..." with the slider at 50 or lower (surprise!).