Hi i exported a file as a jpeg full size from aperture and it was 3.2MB, when i export that same file (but the master) and change to jpeg in photoshop the file is 8.2MB (these are canon 5Dm2 files 20MB original. why is there such a discrepency and why is aperture throwing away so much data. I have preferences in Aperture set to export Jpeg original size. any idea whats happening? thanks Chris
Chris
I’d say that Photoshop is producing too much information! If you have a 20MB raw I can’t imagine why you would compress it to just 8.2MB, given going to jpeg starts by reducing 12 bits to 8. So zero compression would still get you down to 13MB. So I can’t quite see why you want huge jpegs, but it’s your choice :)
Have a look at the image quality settings you are using in both applications. In Aperture when you select the preset there’s an option at the bottom of the page ‘edit’. In my setup the quality is set to 10; am I right in guessing that you have cranked it up to 12 in Photoshop?
It’s up to you what quality you need; suggest you have a play around and see whether you can tell the difference.
Cheers
d.
d.
David, Chris,
I’ve been advised by a printer I trust implicitly that anything above JPEG quality 10 is marketing hype and a waste of space. If you have Photoshop, it’s really easy to compare. Export the same image at 10 and 12 (and any other number of settings), and stack them as unique layers in Photoshop. Comparing two layers (qualities) at a time, set the blend mode to Difference on the top layer. When there’s no difference (i.e. where the pixels are identical) you will see solid black. As you see shades of grey and colors, you see differences between the two layers/qualities. You’ll see it mostly around the edges, but as you get into the higher and higher qualities, the differences are negligible.
Set one of those comparison layers as the original uncompressed file (export as a TIF) so you have a baseline to compare to.
It’s an interesting experiment and can be very eye-opening, and very educational.
-Joseph @ApertureExpert
@PhotoJoseph
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