[Gimp-user] Need help repairing image

["Ronald F. Guilmette" <rfg tristatelogic com>]

The following file was generated from a recent scan of a 40 year old
6x7cm color negative:

  ftp://ftp.tristatelogic.com/private/gimp/img001-b.jpg

Despite the fact that the negative in question has been stored for the
past 30+ years in a manner that I personally would have judged to be
``safe'', as you can plainly see (and as is also quite evident, just
looking at the negative itself) there has been some quite serious
degradation of the image.  Specifically, the negative has been seriously
compromised (by what, I have no idea) in a way that has resulted in
a pronounced, large, and diffuse green streak all along the right hand 
edge of the image.  Less obvious, but also apparent upon close inspection,
there is also some similar (but less pronounced) green discoloration in
a streak along the length of the left hand edge of the image also.

If at all possible I would like to use gimp to restore this image back
to it's former and original glory.  (The image itself means a lot to me
personally.)  Unfortunately, I'm still very much of a gimp novice.  I've
mastered some basic retouching techniques, using the airbrush tool, and
I've also have dabbled around with the fast Fourier plug-in for gimp
(which I found terrifically useful for one project).  But really, these
few things are about all I know of gimp, other than how to crop with it.

So anyway, I'd very much appreciate any advice that anybody would like
to share with me about this image.  Obviously, my goal is to get rid of
the green stripes while (if possible) still preserving as much of the
underyling image detail in the discolored parts of the image as possible.
(As you can see, there is really quite a lot of image detail underneath
those green streaks.)

I tried, briefly, using Gimp's built-in "destripe" function, but that
really didn't seem to help much, no matter how I played with the relevant
sliders.  I also read this page:

   http://docs.gimp.org/en/gimp-tool-blend.html

about Gimp's blend tool, but that does not sound like it would be at all
relevant to this problem.

I don't know enough about the "heal tool" to know if it would be useful for
this kind of problem or not (but I suspect not).

I also read a little bit about the "Wavelet decompose" plug-in:

   http://registry.gimp.org/node/11742

It seems to me like this might possibly be of use in my efforts to kill the
green stripes, but I'm not at all sure and would like some advice before
proceeding.  (I was thinking that maybe the green stripes could be removed
by doing a wavelet decompose and then removing then from the "residual"
part of the image.  Yes?  No?)

So anyway, advice would be appreciated.

I _could_ just crop the green stripes out, but I really prefer not to.
(I would much rather learn more about the multitude of capabilities of
the Gimp.)

If only there were an airbrush-like tool that allowed one to selectively
modify things like color balance, brightness, saturation, and so forth,
then I think that I could clean this image up by hand, but gimp don't
seem to have such things. :-(


Regards,
rfg


P.S.  Before signing up for this list, and before posting here, I read this
page about gimp mailing lists:

   http://www.gimp.org/mail_lists.html

I just wanted to say that I found this part most humorous:

    *   Use the English language.  English is the official language of the
        lists.  There is people from all around the globe so we use it...

Obviously, that's a typo.  It should have said "There AM people from all
around the globe..."

There.  I'm glad that we got that straightened out.