I ran a test out of the latest 2014 build on OSX and couldn't see a meaningful difference. My test was a placed RGB psd with text exported to PDF/x-4. My tests stayed as sRGB throughout.
Here's 100% and 400%
And here are the actual jpegs:
Thank you for running your test!
Since posting (and just before reading your reply), I discovered an additional constraint on replicating the issue:
–it only appears when the linked image has been upscaled* (in my example, 107.1%)
*keep in mind, the PDF was upscaled to the same degree, ruling out it being solely an upscaling issue
–testing at 'even-magnification' scales (i.e. 150%) simply resulted in increased pixelation compared to the same PDF export (see samples below)
–testing at 'odd-magnification' scales (i.e. 101%) generated random artifacts (like those visible in the samples of my initial post)
–as such, this is likely more of a resampling/aliasing issue than jpg-artifacting.
That is, it would seem that upscaled images seem to enjoy a higher-quality resampling method when exported as PDFs.
I'd be curious to see how your test fared with upscaled images.
image scaled at 150%, exported as PDF (compression set to JPG, maximum quality)
image scaled at 150%, exported as JPG (maximum quality, anti-alias**)
**tested with & without anti-aliasing, results were identical
I've always maintained that InDesign export to JPEG was poor quality.
I always export to PDF with no compression and then save as JPEG/TIFF/PSD/PNG from there.
I'll check with scaling. What's your OS?
Mac OS X 10.9.5
Wonder what I'm doing that's different? Here are my JPEG export and PDF Open dialogs. My PDF export is to PDF/X-4 with no sampling. Note that I'm using the trim box and and matching color spaces. With these settings my comparison file pixel dimensions match exactly.
I just tried with transparency and it was OK, but is there transparency on your page?
Could either of you post your test ID page and image?
Exact same settings I use when importing the PDF to photoshop.
Also - using the same export settings in InDesign.
Any transparency? I assume your placed file is linked? What's its format and color space?
It's a JPEG - it's RGB and it's just 1 image placed on a page.
Export to JPEG at 300
Export to PDF at 300
Yields different results in terms of artifacts when viewed in photoshop.
I can see it in your capture, but I'm not getting anything like what you are showing. Weird.
I wonder if it's a Mac vs Pc thing?
Will I send you the image as I have - and see if you get the same result.
Mines a stock image so it might be that - but I don't see how.
Mac OS X 10.9.5
There's also a problem in OSX with the file kind being wrong, which causes problems with placing the JPEG in other apps
Try this Applescript (OSX only):
It exports a JPEG via PDF. I've added a few things to the dialog. You can make a color conversion on export, export to a defined pixel width, and open directly into PS. I haven't thoroughly tested so let me know if there's a problem.
I think this test positively proves that the issue lies within InDesign's JPG resampling algorithm:
I exported a jpg of a single spread with the same image featured twice, once at 25% scale, and once at 33.3% (image reversed to aid in comparison).
Effective PPI's are 1200 & 900, so the disparity can only be explained by the scaling algorithm.
Here's a 100% crop:
Also, as expected, the image quality is far closer to identical in the exported PDF.
Did you try my script?