Editing JPEGs and losing information

[Resending because my edit to remove lots of Apple Mail gobbledygook
was a mistake, and caused the message not to display in some clients.
Please, folks, turn off all your PGP and S/MIME signatures, and don't
use styles of any sort. -Adam]

I've been following Charles Maurer's articles with interest this month.
I couldn't wait so I actually bought a new camera before hearing his
recommendations. I chose a Canon A95 since it was about $300 and it had
a large sensor. Hopefully that means it captures more light. I don't
know how he determined that 5 megapixel Bayer was approximately 35mm
quality but I chose based on that.

I wonder about the role of saving as JPEG as his process. I'm on a
budget so none of the cameras I was considering has a 'RAW' format. My
budget process (after reading Charles' article about perfectionism)
includes:

1. iPhoto to airbrush/red eye remove, if needed.
2. PixelNHance to remove noise, bump up saturation, rebalance
brightness and contrast.
3. iPhoto to Crop and Resize, if needed.

If I understand the process right, I'm getting 4 Lossy JPEG saves --
One inside the camera, and then one at each of the steps mentioned
above. The pictures look better when I'm done. I suppose I could
combine the first and third steps to eliminate 1 save. But is there a
budget way (i.e., simple workflow, free tools) to reduce the number of
saves? Or is that even an appropriate goal?

<http://db.tidbits.com/getbits.acgi?tbart=07832>

Jonathan

On 10/28/04 at 7:40 AM, Jonathan Ploudre <jploudrefastmail.fm> wrote:

> I've been following Charles Maurer's articles with interest this
> month.

Great stuff.

> If I understand the process right, I'm getting 4 Lossy JPEG saves --
> One inside the camera, and then one at each of the steps mentioned
> above. The pictures look better when I'm done. I suppose I could
> combine the first and third steps to eliminate 1 save. But is there a
> budget way (i.e., simple workflow, free tools) to reduce the number
> of saves? Or is that even an appropriate goal?

You could try the GIMP. It's free, powerful, and not too painful to use,
once you get a handle on how things are laid out. The official
documentation is spotty and some of it appears to be out of date, but
there is a lot of good info scattered about the WWW. I found it
frustrating to get going with, but after all it is free.

I've only recently started using it (I don't even own a digital camera,
just borrow one occasionally), but I've been amazed at how much better
many of my photos look after a few simple steps in the GIMP --
auto-adjusting the levels and playing with the output curves a bit.

--
Jeff Soo
jsoomindspring.com

On Oct 28, 2004, at 8:40 AM, Jonathan Ploudre wrote:

> If I understand the process right, I'm getting 4 Lossy JPEG saves --
> One inside the camera, and then one at each of the steps mentioned
> above. The pictures look better when I'm done. I suppose I could
> combine the first and third steps to eliminate 1 save. But is there a
> budget way (i.e., simple workflow, free tools) to reduce the number of
> saves? Or is that even an appropriate goal?

Sure! Once you bring them in from your camera, re-save them or
otherwise convert them into a lossless format. (Photoshop, TIFF, or
your "native" photo editor program's format if you aren't using
Photoshop.) That way you only have one lossy JPEG save (in the camera.)
If you then save out your final file in a lossless interchange format
(e.g. TIFF), you don't even have a final lossy save until you export
for the web/email/whatever.

Note that TIFFs can be compressed in a variety of fashions. TIFFs saved
with LZW or ZIP compression are lossless and can be used if file space
is of concern. Just avoid saving TIFFs with JPEG compression, since
that will lose data just the same as a JPEG would.

--Nik

On Oct 29, 2004, at 8:41 AM, Jonathan Ploudre (by way of Adam C. Engst)
wrote:

> But is there a
> budget way (i.e., simple workflow, free tools) to reduce the number of
> saves? Or is that even an appropriate goal?

One other thing... Apple's "Preview" app will let you convert JPEGs to
TIFFs and various other lossless formats. Far as free tools go, it's a
good one.

--Nik

On Thursday, October 28, 2004, at 10:40 AM, Jonathan Ploudre wrote:
> If I understand the process right, I'm getting 4 Lossy JPEG saves --
> One inside the camera, and then one at each of the steps mentioned
> above. The pictures look better when I'm done. I suppose I could
> combine the first and third steps to eliminate 1 save. But is there a
> budget way (i.e., simple workflow, free tools) to reduce the number of
> saves? Or is that even an appropriate goal?

Graphic converter! and it's already sitting in your Applications
folder. There's even a nifty slide show feature.

JPEG is a very lossy compression method, and I'd suggest working with
higher resolution TIFFS, as you'll avoid loosing information before
you're done working with the file.

Then you can convert to a lower resolution JPEG if you're going to be
posting the photo on the web.

There's a good explanation of the various photo file formats here:

http://www.designer-info.com/master.htm?http://www.designer-info.com/Writing/bmp_tiff_jpeg_gif.htm

Marilyn

Apparently, iPhoto performs some special tricks to avoid the deterioration of quality through subsequent JPEG savings. I don't know any details, but you can try for yourself to save several versions of an edited photo from iPhoto - I didn't notice any loss of quality.

In addition, iPhoto ALWAYS saves the original of a photo. So if you have edited a photo in a way you regret, iPhoto will always allow you to return to the original state.

On 10/11/2004 6:23 AM, "Oliver Voelckers" <oliver.tbtech21.de> spake thus:

> Apparently, iPhoto performs some special tricks to avoid the deterioration of
> quality through subsequent JPEG savings.

You can certainly do 90 degree rotations of JPEGs without losing any
information, and possibly transpositions (flip horizontal/vertical) as these
are fairly simple transformations. Anything else will probably result in
recompression and information loss, however.

--
Nigel Stanger, Dunedin, NEW ZEALAND.
http://public.xdi.org/=nigel.stanger

On 11/10/2004 11:35, "Nigel Stanger" <nstangerinfoscience.otago.ac.nz>
wrote:

> On 10/11/2004 6:23 AM, "Oliver Voelckers" <oliver.tbtech21.de> spake thus:
>
>> Apparently, iPhoto performs some special tricks to avoid the deterioration of
>> quality through subsequent JPEG savings.
>
> You can certainly do 90 degree rotations of JPEGs without losing any
> information, and possibly transpositions (flip horizontal/vertical) as these
> are fairly simple transformations. Anything else will probably result in
> recompression and information loss, however.

Note the "Revert to Original" File menu item. That implies the original is
kept around. I suspect the original is kept, and a list of transforms that
have been applied is recorded. When the image is viewed, the transforms are
played back against the original. Then, perhaps at Export time, the
transforms would be applied to a file being saved.

[To be clear, iPhoto makes a copy of the original as soon as any destructive edit is started, and all edits are applied to that copy (which is itself a real JPEG, not some sort of edit list. The original is retained in a separate folder to enable Revert to Original. -Adam]

But...I haven't used iPhoto much (the lack of a camera better than a
not-modern cell phone one has something to do with that), and I don't have
the current iPhoto (I have 2.0.1, the last one Apple was willing to give
me...I don't have enough need to buy iLife to get the newer iPhoto).

  --John