Jpegs and image quality redux - NG image
| October 17, 2007 11:08AM |
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Not wanting to further hijack Roger's thread with his nice images, I thought I'd finish my jpeg thoughts as a separate topic.
The links which follow are to the same image. This image is a torture test for jpeg compression, as it features nicely saturated colors, and a great deal of very sharp (in fact, I intentionally accentuated the sharpening a bit) high-frequency detail. The actual image is 930x620 pixels, on a grey background of 1150x800.
The first image was saved in Photoshop (Save as...) at maximum jpeg quality, and is a bit over 900k in size. The second was saved in Irfanview, at modest compression to bring the size down to what I generally try to stick with as a compromise and is just over 200k.
Are there differences? Yep, but you'll have to sit and A-B them in an editor or viewer to see 'em, and even then you really won't see any appreciable difference in quality, and that's the real point here.
Dialup Warning! Open the first image at your peril!
Large jpeg image
Compressed jpeg image
The bottom line? You can maintain quality with moderate jpeg compression for web viewing. Huge file sizes for web-sized images are overkill and offer no real advantages. See for yourself.
Oh, and... the image is of NG subject matter.
Scott
Edited 2 time(s). Last edit at 10/17/2007 11:23AM by Scott Turner.
The links which follow are to the same image. This image is a torture test for jpeg compression, as it features nicely saturated colors, and a great deal of very sharp (in fact, I intentionally accentuated the sharpening a bit) high-frequency detail. The actual image is 930x620 pixels, on a grey background of 1150x800.
The first image was saved in Photoshop (Save as...) at maximum jpeg quality, and is a bit over 900k in size. The second was saved in Irfanview, at modest compression to bring the size down to what I generally try to stick with as a compromise and is just over 200k.
Are there differences? Yep, but you'll have to sit and A-B them in an editor or viewer to see 'em, and even then you really won't see any appreciable difference in quality, and that's the real point here.
Dialup Warning! Open the first image at your peril!
Large jpeg image
Compressed jpeg image
The bottom line? You can maintain quality with moderate jpeg compression for web viewing. Huge file sizes for web-sized images are overkill and offer no real advantages. See for yourself.
Oh, and... the image is of NG subject matter.
Scott
Edited 2 time(s). Last edit at 10/17/2007 11:23AM by Scott Turner.
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488 stops for water at Los Pinos tank on closing day Oct. 1979. Photo courtesy Don Richter
The NGDF was started by Don Richter and is currently operated in his memory by Nathan Holmes and others. Others who have contributed to the upkeep of this board are (in no particular order): Charles McCandless, Everett Lueck, Ted Wilton, Cole Adams, James Bane, John Moellmer, Jon Bentz, Linn Moedinger, lloyd lehrer, Rod Jensen, John Craft, Steven Forney, Herb Kelsey, Bill Ramaley, Russ Sperry (El Russo Loco), Josh McNeal, John West, Jim Armstrong, Bob Bergstrom, Greg Scholl, Blake Forbes Doug van Veelen and Mark Fuller.