restoring faded transparencies

[Bernhard S.]

I was scanning a lot of colour transparencies, some taken up to 40 years ago,
and found that in some cases the colours had deteriorated badly.  After a lot
of experimenting I have developed an automatic way of improving the digital
scans using gimp.  I have put a technical article, the gimp plug-in, and a
collection of the good and bad results at
www.lionhouse.plus.com/photosoftware/restore. I would be interested in hearing
from anyone who has worked on this problem and if you try the plug-in let me
know how it works for your pictures.
--
geoff
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[Norman Silverstone-2]

> I was scanning a lot of colour transparencies, some taken up to 40 years ago,
> and found that in some cases the colours had deteriorated badly.  After a lot
> of experimenting I have developed an automatic way of improving the digital
> scans using gimp.  I have put a technical article, the gimp plug-in, and a
> collection of the good and bad results at
> www.lionhouse.plus.com/photosoftware/restore. I would be interested in hearing
> from anyone who has worked on this problem and if you try the plug-in let me
> know how it works for your pictures.

Although your maths is way above my head your results are most
impressive. I have worked with old colour transparencies most of which
are Kodak processed and have been stored in relatively good conditions.
They were copied using an attachment to my digital camera and processed
using UFRaw and Gimp. I will be happy to try your plug-in especially if
it will work with RAW images. Please let me know which is the best to
use JPEG or RAW.

Norman

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[Bernhard S.]

>
>> I was scanning a lot of colour transparencies, some taken up to 40 years
ago,
>> and found that in some cases the colours had deteriorated badly.  After a
lot
>> of experimenting I have developed an automatic way of improving the
digital
>> scans using gimp.  I have put a technical article, the gimp plug-in, and
a
>> collection of the good and bad results at
>> www.lionhouse.plus.com/photosoftware/restore. I would be interested in
hearing
>> from anyone who has worked on this problem and if you try the plug-in let
me

>> know how it works for your pictures.
>
>Although your maths is way above my head your results are most
>impressive. I have worked with old colour transparencies most of which
>are Kodak processed and have been stored in relatively good conditions.
>They were copied using an attachment to my digital camera and processed
>using UFRaw and Gimp. I will be happy to try your plug-in especially if
>it will work with RAW images. Please let me know which is the best to
>use JPEG or RAW.
>
>Norman
>
>

I have no experience of UFRaw.  If you can get your images into gimp my
plug-in should work.  I have just changed it to remove the saving of debug
data.  I will be interested in your experience.
Geoff

--
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[bgw-2]

geoff wrote:
> I was scanning a lot of colour transparencies, some taken up to 40 years ago,
> and found that in some cases the colours had deteriorated badly.  After a lot
> of experimenting I have developed an automatic way of improving the digital
> scans using gimp.  I have put a technical article, the gimp plug-in, and a
> collection of the good and bad results at
> www.lionhouse.plus.com/photosoftware/restore. I would be interested in hearing
> from anyone who has worked on this problem and if you try the plug-in let me
> know how it works for your pictures.
>  
Beautiful work, Geoff. Looks like it might be something that could be
expanded into other kinds of exposure problems.
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[saulgoode]

Quoting geoff <forums@...>:

> I was scanning a lot of colour transparencies, some taken up to 40 years ago,
> and found that in some cases the colours had deteriorated badly.  After a lot
> of experimenting I have developed an automatic way of improving the digital
> scans using gimp.  I have put a technical article, the gimp plug-in, and a
> collection of the good and bad results at
> www.lionhouse.plus.com/photosoftware/restore. I would be interested  
> in hearing from anyone who has worked on this problem and if you try
> the plug-in let me know how it works for your pictures.

Your script produces some very impressive results and your methodology  
is quite ingenious. I especially like how you exploit the quantization  
capabilities of GIMP (i.e., using Indexed colormaps).

I was wondering what licensing your script is released under. There is  
room for improvement of your script, particularly with regard to its  
behavior as a GIMP plug-in and it would be easier to develop your  
script further if it were licensed to allow the sharing of derivatives  
(GPL, BSD, etc). This is especially true if your main interest lies  
with the image algorithms and you are less interested in the demands  
of the GIMP plug-in interface (e.g., handling UNDO, honoring  
selections, providing more flexible utility, menu location, etc). One  
thing that should be fixed fairly soon is that your script seems to  
produce a hidden image (i.e., no "view" associated) and neglect to  
remove it when finished.

Regards.

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[Doug-11]

geoff wrote:
> I was scanning a lot of colour transparencies, some taken up to 40 years ago,
> and found that in some cases the colours had deteriorated badly.  After a lot
> of experimenting I have developed an automatic way of improving the digital
> scans using gimp.  I have put a technical article, the gimp plug-in, and a
> collection of the good and bad results at
> www.lionhouse.plus.com/photosoftware/restore. I would be interested in hearing
> from anyone who has worked on this problem and if you try the plug-in let me
> know how it works for your pictures.
>  
I have a large collection of old slides showing all the problems you
describe in your article to greater or lesser degree, so
I was extremely interested in your post. I've downloaded your plugins.
Unfortunately  I get a "Forbidden" error when I try to download the
readme.txt; and it's not clear to me how to get the python plugins
actually installed in Gimp 2.6 after copying them into the
~/.gimp-2.6/plugins directory.
Can you help?

Doug
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[Norman Silverstone-2]

< snip >

> I have a large collection of old slides showing all the problems you
> describe in your article to greater or lesser degree, so
> I was extremely interested in your post. I've downloaded your plugins.
> Unfortunately  I get a "Forbidden" error when I try to download the
> readme.txt; and it's not clear to me how to get the python plugins
> actually installed in Gimp 2.6 after copying them into the
> ~/.gimp-2.6/plugins directory.
> Can you help?

I read the photorestore.pdf file.

Norman

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[Norman Silverstone-2]

< snip >
> >
> I have no experience of UFRaw.  If you can get your images into gimp my
> plug-in should work.  I have just changed it to remove the saving of debug
> data.  I will be interested in your experience.
> Geoff
>
I have tried with the plug-in but, unfortunately, I cannot detect
anything happening. I use Gimp 2.6.X and Ubuntu 10.4 and I will try to
explain what I did. I downloaded the file, installed it in the
appropriate plug-ins folder and set the permissions to execute. The
entry Batch Restore appeared in Gimp at the bottom of Filters. With a
slide copy loaded in Gimp I selected Batch Restore and a window opened
headed python-fu_batch_restore offering various options. I tried various
Degree of Restoration settings with Make less blue and also tried
turning Make less blue to No but in all cases on clicking OK the window
immediately closed and nothing seems to happen.

The image I am working with was prepared by photographing the slide
using a close up attachment and is the JPG image straight from the
camera.

Am I doing something wrong or should I assume that the slide which is
getting on for 30 years old and from which the copy was made has no
deterioration in the colours?

Norman

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[Tobias Jakobs-2]

Hi,

I have problems to open the readme.txt:
http://www.lionhouse.plus.com/photosoftware/restore/readme.txt
403 Forbidden
You don't have permission to access /photosoftware/restore/readme.txt
on this server.

On Sun, Feb 22, 2009 at 11:51, geoff <forums@...> wrote:
> www.lionhouse.plus.com/photosoftware/restore. I would be interested in hearing
> from anyone who has worked on this problem and if you try the plug-in let me
> know how it works for your pictures.

Where can I find the plugin?

Regards,
Tobias
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[Bernhard S.]

>< snip >
>> >
>> I have no experience of UFRaw.  If you can get your images into gimp my
>> plug-in should work.  I have just changed it to remove the saving of
debug

>> data.  I will be interested in your experience.
>> Geoff
>>
>I have tried with the plug-in but, unfortunately, I cannot detect
>anything happening. I use Gimp 2.6.X and Ubuntu 10.4 and I will try to
>explain what I did. I downloaded the file, installed it in the
>appropriate plug-ins folder and set the permissions to execute. The
>entry Batch Restore appeared in Gimp at the bottom of Filters. With a
>slide copy loaded in Gimp I selected Batch Restore and a window opened
>headed python-fu_batch_restore offering various options. I tried various
>Degree of Restoration settings with Make less blue and also tried
>turning Make less blue to No but in all cases on clicking OK the window
>immediately closed and nothing seems to happen.
>
>The image I am working with was prepared by photographing the slide
>using a close up attachment and is the JPG image straight from the
>camera.
>
>Am I doing something wrong or should I assume that the slide which is
>getting on for 30 years old and from which the copy was made has no
>deterioration in the colours?
>
>Norman
>
>

Sorry you are having problems.  It sounds to me that you are confusing the
"batch_restore" plug-in with the "restore" plug-in.  The former is for doing a
whole set of photographs.  The latter is for a single one. Load the image into
gimp and go to the "restore" menu at the top of the window.  It should open a
new window containing the restored image.
Geoff

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[Norman Silverstone-2]

< snip >

> Sorry you are having problems.  It sounds to me that you are confusing the
> "batch_restore" plug-in with the "restore" plug-in.  The former is for doing a
> whole set of photographs.  The latter is for a single one. Load the image into
> gimp and go to the "restore" menu at the top of the window.  It should open a
> new window containing the restored image.

My most sincere apologies. I must be getting too old for this game, this
idiot loaded the wrong plug-in. Load the correct file and all is well
and works like a charm. Now, perhaps when I have refreshed my brain, I
will have a serious look at what can be done.

Norman

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[Alec Burgess]

Tobias Jakobs (tobias.jakobs@...) wrote (in part)  (on
2009-02-22 at 14:51):
> On Sun, Feb 22, 2009 at 11:51, geoff forums@... wrote:
> > > www.lionhouse.plus.com/photosoftware/restore. I would be
> interested in hearing
> > > from anyone who has worked on this problem and if you try the
> plug-in let me
> > > know how it works for your pictures.
>
> Where can I find the plugin?
@Tobias - since Geoff hasn't had time to respond ...
Go up one level (click Parent Directory) then down to gimp_plugins
http://www.lionhouse.plus.com/photosoftware/gimp_plugins/
restore.py  is the one discussed in the PDF - the others may also be of interest.



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[Bernhard S.]

>Quoting geoff <forums@...>:
>
>> I was scanning a lot of colour transparencies, some taken up to 40 years
ago,
>> and found that in some cases the colours had deteriorated badly.  After a
lot
>> of experimenting I have developed an automatic way of improving the
digital
>> scans using gimp.  I have put a technical article, the gimp plug-in, and
a

>> collection of the good and bad results at
>> www.lionhouse.plus.com/photosoftware/restore. I would be interested  
>> in hearing from anyone who has worked on this problem and if you try
>> the plug-in let me know how it works for your pictures.
>
>Your script produces some very impressive results and your methodology  
>is quite ingenious. I especially like how you exploit the quantization  
>capabilities of GIMP (i.e., using Indexed colormaps).
>
>I was wondering what licensing your script is released under. There is  
>room for improvement of your script, particularly with regard to its  
>behavior as a GIMP plug-in and it would be easier to develop your  
>script further if it were licensed to allow the sharing of derivatives  
>(GPL, BSD, etc). This is especially true if your main interest lies  
>with the image algorithms and you are less interested in the demands  
>of the GIMP plug-in interface (e.g., handling UNDO, honoring  
>selections, providing more flexible utility, menu location, etc). One  
>thing that should be fixed fairly soon is that your script seems to  
>produce a hidden image (i.e., no "view" associated) and neglect to  
>remove it when finished.
>
>Regards.
>
>

Thanks for your message.  As you deduce I am more interested in the
processing algorithm than the coding.  There are too many poor results at the
moment and I suspect there will be modifications to the method when I have
more experience of its performance.  For this reason I have not put it on a
gimp site.  I am happy for anyone to develop the plug-in further and improve
the interface but there is not much point until the algorithm is unlikely to
change.  I have killed the spurious hidden image which was left over from the
way of correcting the side absorptions.


--
geoff
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[Doug-11]

norman wrote:

> < snip >
>
>  
>> I have a large collection of old slides showing all the problems you
>> describe in your article to greater or lesser degree, so
>> I was extremely interested in your post. I've downloaded your plugins.
>> Unfortunately  I get a "Forbidden" error when I try to download the
>> readme.txt; and it's not clear to me how to get the python plugins
>> actually installed in Gimp 2.6 after copying them into the
>> ~/.gimp-2.6/plugins directory.
>> Can you help?
>>    
>
> I read the photorestore.pdf file.
>
> Norman
>  

So did I, but there's no protection against senility :-[ .
However, I then read your earlier post, Norman - bangs head on wall!! -
of course, permissions :-[ :-[
(it's normally the first thing I think of, but my excuse is that I've
got used to gramps, where 'Reload Plugins' does that for you).

Yes, they're all there. Now I can get down to trying them out.

Doug

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[Norman Silverstone-2]

< snip >

> Thanks for your message.  As you deduce I am more interested in the
> processing algorithm than the coding.  There are too many poor results at the
> moment and I suspect there will be modifications to the method when I have
> more experience of its performance.  For this reason I have not put it on a
> gimp site.  I am happy for anyone to develop the plug-in further and improve
> the interface but there is not much point until the algorithm is unlikely to
> change.  I have killed the spurious hidden image which was left over from the
> way of correcting the side absorptions.


Geoff, I have started to look at a number of copies of old Kodachrome
slides and I am beginning to get together several comments many of which
would be best exemplified by examples. Therefore, I would like to know
whether, at this stage in the development and because of your main
interest being in the algorithm, you and other readers would think it
best if this subject was continued outside this list.

Norman  

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[Doug-11]

norman wrote:

> < snip >
>
>  
>> Thanks for your message.  As you deduce I am more interested in the
>> processing algorithm than the coding.  There are too many poor results at the
>> moment and I suspect there will be modifications to the method when I have
>> more experience of its performance.  For this reason I have not put it on a
>> gimp site.  I am happy for anyone to develop the plug-in further and improve
>> the interface but there is not much point until the algorithm is unlikely to
>> change.  I have killed the spurious hidden image which was left over from the
>> way of correcting the side absorptions.
>>    
>
>
> Geoff, I have started to look at a number of copies of old Kodachrome
> slides and I am beginning to get together several comments many of which
> would be best exemplified by examples. Therefore, I would like to know
> whether, at this stage in the development and because of your main
> interest being in the algorithm, you and other readers would think it
> best if this subject was continued outside this list.
>
> Norman  
>  

The subject's of considerable interest to me and I'd like to be kept
aware of any developments. So for my 0.02c worth, I'd prefer it to stay
on the main list.

Doug
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[Bernhard S.]

>I was scanning a lot of colour transparencies, some taken up to 40 years
ago,
>and found that in some cases the colours had deteriorated badly.  After a
lot
>of experimenting I have developed an automatic way of improving the digital
>scans using gimp.  I have put a technical article, the gimp plug-in, and a
>collection of the good and bad results at
>www.lionhouse.plus.com/photosoftware/restore. I would be interested in
hearing
>from anyone who has worked on this problem and if you try the plug-in let
me
>know how it works for your pictures.
>
Thanks for all the interest.  By publicizing my plug-in I hope that: (1)
people with faded slides will be able to restore them, (2) that it will be
possible to improve the method by input from others and (3) if (2) happens
someone will take up the task of improving the coding so that the plug-in can
be distributed more widely.

I think that we should keep general discussion of this topic in this forum,
so that everyone can join in, but it would be useful if there was a single
collection of sample images, with commentary and perhaps carefully considered
reviews of the conclusions made from them.  I am happy to put these on my
website along with my own examples.  My email is geofxf@... (delete the
x y and z to get the correct address and avoid my getting spam).  Please keep
the file size down, the pictures will only be viewed on a webpage.  Also be
selective about what you send; images similar to existing ones are not very
useful, but examples of good restorations of very poor originals are of
interest as are failures of the method.  It is probably also better if any
very technical discussions are done by email.
--
geoff
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[Norman Silverstone-2]

First, to put things into context. It was always a source of frustration
that one was not able to manipulate colour transparancies in the same
way that black and white negatives could be manipulated in the darkroom.
(Amateur colour printing had not yet arrived). So, when I had set up my
digital darkroom I decided to investigate copying and manipulating some
of my old colour slides. After studying the literature, I decided to
make copies using my Olympus SP-500 UZ with an adjustable close-up
attachment with supplementary lenses attached to the front of the
camera. Images were recorded in both RAW and JPEG.

Images for this exercise were selected, more or less at random, from
those which had been made from  Kodachrome 25 colour transparencies
which were about 30 years old. Only JPEG images as produced by the
camera were used and no attempt has been made to produce the correct,
restored image but rather to be able to compare the results obtained
from the two extremes of the slider setting and the original copy. Also,
as this was not a debuging exercise, no reference has been made to any
images which caused error messages to be displayed. The settings were
'Make less blue' -> Yes, 'Combine all layers' -> Yes and 'Degree of
Restoration' slider settings were either 1.2 or 0.7.

The images are available at www.littletank.org/upload and are arranged
in groups of 3. The left-hand image is the original slide copy, the
centre image is with the slider set at 1.2 and the right-hand image is
with the slider set to 0.7. You are free to use these images for any
tests, measurements or observations you care to make and if you have any
questions please do not hesitate to ask. All I ask is that if you want
to use any of them in any publication, please let me know.

So far, the process looks very encouraging but there must be many
questions to be answered before it will be possible to comment with
confidence on the use of the Restore plug-in. For example, what effect,
if any, is there on the fine detail stored within the original
transparency.

I hope that these observations and the images will prove to be useful.

Norman
                 
 

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[Norman Silverstone-2]

It would be useful if the slider range could be altered, especially to
be able to go below 0.7. I am not a programmer and, therefore, I do not
know if this is possible or how complicated it is but, if it can be
done, I would love to be able to try the effect.

Norman

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[Doug-11]

norman wrote:

> It would be useful if the slider range could be altered, especially to
> be able to go below 0.7. I am not a programmer and, therefore, I do not
> know if this is possible or how complicated it is but, if it can be
> done, I would love to be able to try the effect.
>
> Norman
>
> _______________________________________________
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>
>  

The restore plug-in works very well indeed for me in general.
I'd also like to be able to set a degree of restoration below 0.7.

I have a couple of comments:
(1) With some slides, restoration of 1.2 causes the plugin to crash with
"setting out of bounds"
(2) I have a couple of problematic slides I've sent on to Geoff for him
to explore possible limitations of the algorithm:
     (i) One, an Ektachrome dating from 1981, is puzzling. The
appearance isn't exceptional; it has a slightly greenish cast. All
adjustments make a noticeable difference to the appearance; but they all
(setting the sliders 0.7 -1.2, less blue yes/no, combine all layers
yes/no) end up with images that have little or no discernible
differences between them.
    (ii) The other, an Ektachrome from 1977, is representative of a
certain number of 30-year old slides where the blue colour seems to have
been completely destroyed, giving bright yellow skies. It may be
unreasonably challenging for the algorithm and causes the plugin to
crash. But it would be nice if the plugin could make some sort of a stab
at restoration or if not, fail gracefully.
 

Doug
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