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1. Re: Progressive jpegs... oops.
Paulo Skylar Jan 22, 2010 6:52 PM (in response to shoot me now-d3u3se)It may matter! A progressive jpeg may not be readable by all jpeg decoders so you might check woth your book printer. If it can be read, the image quality is identical.
If you open up the jpeg with Irfanview and click on Image > Information the compression box will tell you if it is progressive.
Paulo
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2. Re: Progressive jpegs... oops.
Zeno Bokor Jan 22, 2010 11:43 PM (in response to shoot me now-d3u3se)the progressive option is for the web, it makes the JPG load in passes. It first shows a crappy quality image, then loads a better one and a better one until it gives you the final image.
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3. Re: Progressive jpegs... oops.
John Joslin Jan 23, 2010 12:52 AM (in response to shoot me now-d3u3se)The use of "Progressive" (which fast internet and better browser rendering has made more or less obsolescent) should not affect print reproduction.
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4. Re: Progressive jpegs... oops.
Bill Hunt Jan 23, 2010 8:28 AM (in response to John Joslin)John,
At one time, Mac's had issues with Progressive JPEG's. From your comment, can I assume that this is no longer the case? Just curious.
To the OP, what can often happen with the JPEG settings is that if one has recently Opened a Progressive JPEG (whether they noticed it, or not), and then done a Save, that Progressive setting can still be around. I'm like you, in that I never use it - knowingly. Every now and then, I find that it's the current setting, so I have to blame myself for allowing it to be used previously, and I just did not notice. Same for that All Caps setting in the Characters Palette.
If there are any problems with your pre-press house, or your printer, a simple Action with Baseline Optimized, or similar, should allow for batch conversion.
Good luck,
Hunt
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5. Re: Progressive jpegs... oops.
Paulo Skylar Jan 23, 2010 8:56 AM (in response to Bill Hunt)Bill,
If you meant going back to the original psd files and batching a save to baseline, that's a good way to go. If, however, you meant converting the progressive jpegs to baseline jpegs in Photoshop, then that conversion will loose some information (quality) and the OP indicated his images were high quality. So I would run some visual tests before batch converting. Specialized software does exist to convert between jpg types losslessly - I do not have a name on hand.
Paulo
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6. Re: Progressive jpegs... oops.
Bill Hunt Jan 23, 2010 10:37 AM (in response to Paulo Skylar)Thanks for that. Yes, I meant going back to the originals, but did not state that. Glad that you pointed that out, as Saving a JPEG of a JPEG is not a good idea. Sorry to not state things more clearly.
Hunt
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7. Re: Progressive jpegs... oops.
shoot me now-d3u3se Jan 23, 2010 3:52 PM (in response to Bill Hunt)It turns out that the lab doesn't want me to send progressives, so I re-saved my files as baseline. I discovered a quick way to find out which files were tainted: I just loaded them into my web browser. The progressives rendered as expected with a low rez image appearing first.
Thanks for the replies.
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8. Re: Progressive jpegs... oops.
Paulo Skylar Jan 23, 2010 4:37 PM (in response to shoot me now-d3u3se)Sounds like an effective, practical approach.
That does not work for me. If I open a file locally the rendering hapens too fast to make a determination. I have to access the file via the web to see the difference.
Paulo





