I am sorry that this query is not Gimp specific, but since I use Gimp to
create the images and I don't subscribe to any "images" list, I hope it
will be allowed here. I won't make a habit of it.
From time to time I notice an image in our library or on our website
has "become" negative. This is very unsettling as I have used such
images on our website for years and then all of a sudden I notice in the
middle of a web page an image that is in negative.
Yes, it is theoretically possible that I simply never noticed this, but
I have been finding one every few months now for three or four years. I
know everybody says "I did not do it", but these are images which have
not intentionally been manipulated, processed, or uploaded to the
hosting service for for years. The differences in image appearance are
so dramatic that I just can't believe that they have been like that all
along and I just did not see them.
Also, the images don't seem to suffer any other type of damage. They
just become negative.
In the most recent example case (see links below), only the file
residing on the hosting service has "become" negative. The original
JPEG that I uploaded is still correct! (However, over the last couple
years, I have found an occasional "negative-ized" original JPEG on our
server and also a few "negative-ized" TIFFs on our server. It seems
that the alteration to negative can happen anywhere along the line.
Since the source JPEG version residing on my server is still okay, the
damage happened either during transfer to the hosting service or while
on the hosting service.
Here is an example (the two are images of slightly different objects,
but the overall appearance is supposed to be extremely similar -- the
person who can determine the difference is a keen-eyed philatelist):
My process: All on Linux. After scanning to TIFF, the images are edited
in Gimp as TIFFs. Then they are processed using a script that runs
various ImageMagick actions to create various sizes (copies) as JPEGs.
The source TIFF is preserved unchanged (and the original TIFF for the
negative example above is CORRECT!). The JPEGs are then uploaded to a
hosting service (in this case all the 'original' JPEGs still on my
server are CORRECT!!).
So... The question is..... is there a bit in an image file that can be
hit by a "stray neutrino" (or whatever happens) that can cause the image
file to "become" negative". If yes for JPEG, is it also possible for TIFF?
Or, it seems more likely to me, would such a change from positive to
negative require a very large number of changes to the image file?
If the type of occasional damage I am observing in a "small" library of
about 100,000 image files is happening everywhere, to everybody, to all
types of computer files, we are in deep do-do in the long term. As they
say.... "Houston, we have a problem."
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