Paul
As far as I can see, Photoshop does not "degrade" a JPEG when it rotates
anymore than an application capable of lossless rotation. You can test it:
make a RAW file, make two JPEGs from it, rotate one using "lossless
rotation," use Photoshop to rotate the other, compare them with the RAW
output in Photoshop. Alternatively, make copies of a JPEG output by your
camera and rotate them and compare with the original. I haven't been
listening to the "lossless rotation" user groups and am basing my findings
on the above test method - if it's flawed, please point out the flaws or
supply a less flawed way of testing for degradation caused by Photoshop when
rotating and saving a JPEG.
BTW, iView takes 163 secs to do a lossless rotation on a 3.3MB JPEG and it
takes a couple of seconds to rotate the thumbnail in Photoshop's file
browser and then 2-3 seconds to open and rotate the file and another couple
of seconds to save the file.
A JPEG output from a camera, IMO, is akin to a print from a neg. OTOH, a RAW
output from a camera is akin to a neg because you cannot output an image
from it till you process it (if you want to be pedantic, call it an
unprocessed neg), and you can process it in many ways (as you can print many
versions from one neg), unlike a JPEG, which would be akin to scanning a
print and then processing that if you (meaning one) needs to repurpose it.
That's how I understand it and no amount of persuasion will make me think
otherwise. <g>
As for your workflow, I did say that you (meaning you and/or one) may not
find any advantage in shooting RAW but if you find the "degradation" caused
by outputting a JPEG acceptable as opposed to a RAW output (while in your
workflow JPEGs may not be seen as degraded images, in other workflows they
can be when compared to the advantages of shooting in RAW), then the
"degradation" caused by rotating in Photoshop should be negligible too and
so Photoshop not labelled as an application that "degrades" images. I'm not
trying to convert you. Just putting the opposite POV, and trying to defend
Photoshop.
You wrote: In case anyone is not aware, you can rotate a JPG without saving
it, using certain software, you cannot however, open it in PS, rotate it and
save it, that will degrade your image).
To degrade an image, the change must be noticeable and for the worse. I see
no such thing happening if I rotate a JPEG in Photoshop. It's possible I may
be doing something wrong and I'm happy to be corrected, as always, by
superior knowledge and/or experience.
My view is you *can* open a JPEG in Photoshop, rotate it and save it and
open it again and the "degradation" is no more than what you are accepting
now by shooting JPEGs as opposed to RAWs. When I say degradation, I'm not
implying that you are accepting inferior quality (there's always a trade off
between quality and speed). I mean it in the sense that it's possible to
demonstrate degradation by outputting the same image in RAW and JPEG and
doing 16-bit color correction on the RAW and 8-bit correction on the JPEG.
No prize for guessing which will "degrade" first. However, if your color
balance and exposures are perfect, the degradation will be hard to
demonstrate but not impossible, just depends how far you want to take the
file from the "original" capture.
Also, by rotating in GC, you may produce truly lossless rotation but, as I
said, I don't have that application. So, if you can do the above test and
post your findings, it would be very helpful to the discussion.
Just to be clear, I'm not slamming the JPEG format. I've said many, many
times on this list and others that archiving or sending a file as a full
quality JPEG as opposed to a TIFF is perfectly OK and acceptable *if* space
or speed is a concern. If it's not, save as a PSD or TIFF.
--/ Shangara Singh
:: Adobe Certified Expert ~ Photoshop 7.0
:: Adobe Photoshop 7.0 Essential Tips
:: Exam Aids for Photoshop, Illustrator & Dreamweaver
:: Http://www.shangarasingh.com
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