watermarking software, generation loss

I am interested in putting a visible EXIF date/time stamp on digital photos
but want to minimize generation loss.

If I put a timestamp on a JPEG photo (using say, Exifer or Irfanview), and
assuming I use the same compression ratio that was originally used by the
digital camera - is there any generation loss in the area of the photo
outside the timestamp i just added? Stated otherwise, is the generation
loss limited to the area immediately surrounding the timestamp?

Of course, if I use a different compression ratio, I imagine that the entire
photo would be affected by "generation loss".

Any guidelines on how to minimize generation loss when doing this sort of
thing?

"Spoon2001" writes:

I am interested in putting a visible EXIF date/time stamp on digital photos
but want to minimize generation loss.

If I put a timestamp on a JPEG photo (using say, Exifer or Irfanview), and
assuming I use the same compression ratio that was originally used by the
digital camera - is there any generation loss in the area of the photo
outside the timestamp i just added? Stated otherwise, is the generation
loss limited to the area immediately surrounding the timestamp?

In general, if you open a jpeg in an editing program and resave it,
you will incur generation loss throughout.

Given how jpeg works, it's *conceivable* (i.e. it doesn't contradict
my understanding of how jpeg works) that a program for adding text
over a photo could only resave the portion directly under the text. I
don't know of any that claim to work that way, however.

Of course, if I use a different compression ratio, I imagine that the entire
photo would be affected by "generation loss".

Any guidelines on how to minimize generation loss when doing this sort of
thing?

Don't edit and resave jpegs.
--
David Dyer-Bennet, , http://www.dd-b.net/dd-b/
RKBA: http://noguns-nomoney.com/ http://www.dd-b.net/carry/
Pics: http://dd-b.lighthunters.net/ http://www.dd-b.net/dd-b/SnapshotAlbum/
Dragaera/Steven Brust: http://dragaera.info/

"Spoon2001" writes:

I am interested in putting a visible EXIF date/time stamp on digital photos
but want to minimize generation loss.

If I put a timestamp on a JPEG photo (using say, Exifer or Irfanview), and
assuming I use the same compression ratio that was originally used by the
digital camera - is there any generation loss in the area of the photo
outside the timestamp i just added? Stated otherwise, is the generation
loss limited to the area immediately surrounding the timestamp?

In general, if you open a jpeg in an editing program and resave it,
you will incur generation loss throughout.

Given how jpeg works, it's *conceivable* (i.e. it doesn't contradict
my understanding of how jpeg works) that a program for adding text
over a photo could only resave the portion directly under the text. I
don't know of any that claim to work that way, however.

Of course, if I use a different compression ratio, I imagine that the entire
photo would be affected by "generation loss".

Any guidelines on how to minimize generation loss when doing this sort of
thing?

Don't edit and resave jpegs.
--
David Dyer-Bennet, , http://www.dd-b.net/dd-b/
RKBA: http://noguns-nomoney.com/ http://www.dd-b.net/carry/
Pics: http://dd-b.lighthunters.net/ http://www.dd-b.net/dd-b/SnapshotAlbum/
Dragaera/Steven Brust: http://dragaera.info/