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-   -   Some old jpegs decay and fade. (http://www.velocityreviews.com/forums/t952085-some-old-jpegs-decay-and-fade.html)

Peter Jason 09-12-2012 01:55 AM

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

David Dyer-Bennet 09-12-2012 02:53 AM

Re: Some old jpegs decay and fade.
 
Peter Jason <pj@jostle.com> 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

Martin Brown 09-12-2012 07:31 AM

Re: Some old jpegs decay and fade.
 
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

snapper@mailinator.com 09-13-2012 04:33 AM

Re: Some old jpegs decay and fade.
 
On Wed, 12 Sep 2012 11:55:24 +1000, Peter Jason <pj@jostle.com> 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.


Peter Jason 09-15-2012 07:16 AM

Re: Some old jpegs decay and fade.
 
On Thu, 13 Sep 2012 17:18:16 -0400, Alan Browne
<alan.browne@FreelunchVideotron.ca> 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


Martin Brown 09-15-2012 07:51 AM

Re: Some old jpegs decay and fade.
 
On 15/09/2012 08:16, Peter Jason wrote:
> On Thu, 13 Sep 2012 17:18:16 -0400, Alan Browne
> <alan.browne@FreelunchVideotron.ca> 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)

Peter Jason 09-15-2012 08:13 AM

Re: Some old jpegs decay and fade.
 
On Sat, 15 Sep 2012 08:51:14 +0100, Martin Brown
<|||newspam|||@nezumi.demon.co.uk> wrote:

>On 15/09/2012 08:16, Peter Jason wrote:
>> On Thu, 13 Sep 2012 17:18:16 -0400, Alan Browne
>> <alan.browne@FreelunchVideotron.ca> 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.


Rob 09-16-2012 06:01 AM

Re: Some old jpegs decay and fade.
 
On 15/09/2012 5:16 PM, Peter Jason wrote:
> On Thu, 13 Sep 2012 17:18:16 -0400, Alan Browne
> <alan.browne@FreelunchVideotron.ca> 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.

Martin Brown 09-16-2012 08:03 AM

Re: Some old jpegs decay and fade.
 
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
>> <alan.browne@FreelunchVideotron.ca> 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

HerHusband 09-16-2012 04:08 PM

Re: Some old jpegs decay and fade.
 
Peter,

> 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?


Assuming this isn't a hoax, the only reason a JPG photo (or any digital
file) would change over time is if the media they are stored on is failing
(or a virus has corrupted the files).

The first thing I would do is scan your drive for surface errors. One or
two errors isn't a big deal, they will be mapped so they won't be used
again. But when you start getting bad sectors, it usually escalates fairly
quickly, so I would rescan the drive periodically until you can replace it
with a new drive (which I would do as soon as possible).

Next, I would scan the computer for viruses and spyware. The free
MalwareBytes anti-malware works good for this.

If your JPG's are on optical media, the disc's are probably failing. It is
quite common for CDR's and DVDR's to degrade after a year or two. They
usually degrade from the outer edges inward, so the more you have stored on
the disc, the more likely you'll have data corruption.

Most importantly, you should be backing up your original files regularly.
Drives and media WILL fail, it's just a matter of WHEN. Without backup
copies of your files, you will probably lose them...

Take care,

Anthony Watson
Mountain Software
www.mountain-software.com
Home Cookin Recipe Software
www.mountain-software.com/homecook.htm


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