Some old jpegs decay and fade.

I have some scanned JPEGs from some old photos,
and over time they have faded and become speckled.

This has happened only to a few.

Why has this happened?

Peter

Peter Jason writes:

I have some scanned JPEGs from some old photos,
and over time they have faded and become speckled.

This has happened only to a few.

Why has this happened?

I can't think of a mechanism. Clean your monitor screen, maybe? :-)

Bit errors in a jpeg tend to destroy the image past that point very
visibly. Speckles would almost have to happen when the file was in an
uncompressed state, not in JPEG.

I'll be interested to learn, if we can, what's actually happening.
--
Googleproofaddress(account:dd-b provider:dd-b domain:net)
Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/
Photos: http://dd-b.net/photography/gallery/
Dragaera: http://dragaera.info

On 12/09/2012 02:55, Peter Jason wrote:
I have some scanned JPEGs from some old photos,
and over time they have faded and become speckled.

The old photos or the JPEGs? Light can damage all storage media
including silver images, colour prints, slides, CDs and DVDs.

This has happened only to a few.

Why has this happened?

If you mean to digital media then the answer is bit rot - the disk is
failing. A single bit error in a JPEG can affect the decoding of the
rest of the file. It usually results in a horizontal discontinuity,
possibly a lateral shift and/or a sudden abrupt change in colour to one
of pastel shades, mostly black, psychedelic colours or different ones.

"Speckled" is not a failure mode that I have ever seen unless the damage
is restricted to a single block end (and was corrected immediately by
the end of block code) I can't see how it could happen. I would be
interested to see a sample of a "speckled" JPEG.

There is an outside chance that malware is doing it so do an AV scan
although usually they trash all JPEG image stream content to zeros.

Damaged JPEGs can sometimes be repaired but it is only a realistic
proposition at present for images with serious commercial value.

--
Regards,
Martin Brown

On Wed, 12 Sep 2012 11:55:24 +1000, Peter Jason wrote:

I have some scanned JPEGs from some old photos,
and over time they have faded and become speckled.

This has happened only to a few.

Why has this happened?

Were you suffering a cold when you were viewing them? I suspect you sneezed on your
monitor.

On 2012.09.11 21:55 , Peter Jason wrote:
I have some scanned JPEGs from some old photos,
and over time they have faded and become speckled.

This has happened only to a few.

Why has this happened?

Were the photos repeatedly opened and re-saved?

--
"C'mon boys, you're not laying pipe!".
-John Keating.

On Thu, 13 Sep 2012 17:18:16 -0400, Alan Browne
wrote:

On 2012.09.11 21:55 , Peter Jason wrote:
I have some scanned JPEGs from some old photos,
and over time they have faded and become speckled.

This has happened only to a few.

Why has this happened?

Were the photos repeatedly opened and re-saved?

They have passed thru Microsoft "Digital Image
Suite 9" first as tiff files and then converted to
jpgs (after which the Suite didnt work any more),
but some are OK.

An example of a decayed photo of 1988 scanned in
from negative color film. Note the fine white
snow throught the picture.
http://imageshack.us/a/img832/1747/1988a1decay.jpg

On 15/09/2012 08:16, Peter Jason wrote:
On Thu, 13 Sep 2012 17:18:16 -0400, Alan Browne
wrote:

On 2012.09.11 21:55 , Peter Jason wrote:
I have some scanned JPEGs from some old photos,
and over time they have faded and become speckled.

This has happened only to a few.

Why has this happened?

Were the photos repeatedly opened and re-saved?

They have passed thru Microsoft "Digital Image
Suite 9" first as tiff files and then converted to
jpgs (after which the Suite didnt work any more),
but some are OK.

I don't think that the suite *ever* worked.

What you are seeing in the sample image is noise on an under exposed
image. The light fitting and parts very near the window are fine.

This is not a faulty JPEG it is faulty image processing.

An example of a decayed photo of 1988 scanned in
from negative color film. Note the fine white
snow throught the picture.
http://imageshack.us/a/img832/1747/1988a1decay.jpg

That image has been resaved by Adobe Photoshop level 12 destroying any
evidence that might have been present in the original file.

A despeckle filter might help a bit but you have seriously mangled the
images. Is it mostly indoor photos that have failed?

I need an original sample image at full resolution to see if there is
actually any genuine damage to the JPEG stream. My instinct is that what
you have here is noise on seriously underexposed images. IOW the images
were never right it is just that you didn't notice at the time.

The reason the original file matters is that it will with a bit of luck
contain an independent small thumbnail of what was saved.

--
Regards,
Martin Brown
(my strange looking email address is valid if not modified in any way)

On Sat, 15 Sep 2012 08:51:14 +0100, Martin Brown
wrote:

On 15/09/2012 08:16, Peter Jason wrote:
On Thu, 13 Sep 2012 17:18:16 -0400, Alan Browne
wrote:

On 2012.09.11 21:55 , Peter Jason wrote:
I have some scanned JPEGs from some old photos,
and over time they have faded and become speckled.

This has happened only to a few.

Why has this happened?

Were the photos repeatedly opened and re-saved?

They have passed thru Microsoft "Digital Image
Suite 9" first as tiff files and then converted to
jpgs (after which the Suite didnt work any more),
but some are OK.

I don't think that the suite *ever* worked.

What you are seeing in the sample image is noise on an under exposed
image. The light fitting and parts very near the window are fine.

This is not a faulty JPEG it is faulty image processing.

An example of a decayed photo of 1988 scanned in
from negative color film. Note the fine white
snow throught the picture.
http://imageshack.us/a/img832/1747/1988a1decay.jpg

That image has been resaved by Adobe Photoshop level 12 destroying any
evidence that might have been present in the original file.

A despeckle filter might help a bit but you have seriously mangled the
images. Is it mostly indoor photos that have failed?


I fear they are all processed thru photoshop or
irfanview to get the annotation on the picture. I
have seen too many anonymous pictures to do
otherwise.
Some painters knew all about this.
http://www.flickr.com/photos/3331770...4279/lightbox/




Some outoor shots have the speckling too.

I need an original sample image at full resolution to see if there is
actually any genuine damage to the JPEG stream. My instinct is that what
you have here is noise on seriously underexposed images. IOW the images
were never right it is just that you didn't notice at the time.

The reason the original file matters is that it will with a bit of luck
contain an independent small thumbnail of what was saved.

On 15/09/2012 5:16 PM, Peter Jason wrote:
On Thu, 13 Sep 2012 17:18:16 -0400, Alan Browne
wrote:

On 2012.09.11 21:55 , Peter Jason wrote:
I have some scanned JPEGs from some old photos,
and over time they have faded and become speckled.

This has happened only to a few.

Why has this happened?

Were the photos repeatedly opened and re-saved?

They have passed thru Microsoft "Digital Image
Suite 9" first as tiff files and then converted to
jpgs (after which the Suite didnt work any more),
but some are OK.

An example of a decayed photo of 1988 scanned in
from negative color film. Note the fine white
snow throught the picture.
http://imageshack.us/a/img832/1747/1988a1decay.jpg



Decay?? what you are seeing is a jpeg image that has been compressed
too much. 80-90% compression.

On 16/09/2012 07:01, Rob wrote:
On 15/09/2012 5:16 PM, Peter Jason wrote:
On Thu, 13 Sep 2012 17:18:16 -0400, Alan Browne
wrote:

On 2012.09.11 21:55 , Peter Jason wrote:
I have some scanned JPEGs from some old photos,
and over time they have faded and become speckled.

This has happened only to a few.

Why has this happened?

Were the photos repeatedly opened and re-saved?

They have passed thru Microsoft "Digital Image
Suite 9" first as tiff files and then converted to
jpgs (after which the Suite didnt work any more),
but some are OK.

An example of a decayed photo of 1988 scanned in
from negative color film. Note the fine white
snow throught the picture.
http://imageshack.us/a/img832/1747/1988a1decay.jpg

Decay?? what you are seeing is a jpeg image that has been compressed
too much. 80-90% compression.

No it isn't. The one thing that is *NOT* wrong with it is over
compression. That would produce edge artifacts on sharp transitions.

The image provided is actually saved at the highest quality that
Photoshop offers (which is a complete waste because the content was
already shot to pieces before it was saved).

There is massive noise in the darker areas of the image which strongly
suggests over enthusiastic use of histogram equalisation possibly by
some one-click automagic "improve my photos" software.

--
Regards,
Martin Brown