George R Jaffray, Jr writes:
> BJ: JPEGs are lossy, so I immediately convert photos that
> I want to work on to something else. My question is:
> what do you find to be the most useful nonlossy format
> for this purpose?
Well, PNG or TIFF? Or if you are using only GIMP, its internal XCF
format perhaps.
Many "serious" photographers prefer to have the camera store the
images in so-called RAW format, and not JPEG. The RAW formats are
specific to camera brand and to some extent model, even. They are not
vendor-neutral like JPEG, PNG etc.
See http://en.wikipedia.org/wiki/RAW_image_format .
The most important benefit of RAW is that there is more latitude for
corrections afterwards. But using RAW also means a more complex
workflow, as you then need separate software for the processing
("development") of the RAW images to produce JPEGs, PNGs or TIFFs.
(There are open source raw processors that integrate with GIMP, but
the combination is as far as I know not yet as powerful or good
quality as using a standalone commercial RAW processor. Personally I
use CaptureOne LE for RAW processing.)
You can do most of the common postprocessing steps in the RAW
processor like exposure, contrast and colour balance correction,
cropping, and in some even tilt correction, i.e. arbitrary
rotation. Thus you don't necessarily need to do anything to the
produced images in general image manipulation software like GIMP or
Photoshop afterwards.
BTW, one thing you should know is that cropping of JPEG images can be
done losslessly. If cropping is all you need to do to a photo, it's
always better to do a lossless crop than to load the image into image
manipulation software and crop there, and re-save as JPEG. Google for
";jpegcrop".
--tml
.