Hi Steve,
inspired by your question I am trying to optimize my workflow to use
Vuescan to produce the RAW files and do everything else in darktable.
I like to have "everything in one place", in this case: my complete archive.
And I like non-destructive workflow.
But I fear this will take some more time until I'm ready to post
results. I'll let you know.
Bernhard
Steven Fosdick schrieb am 24.11.2014 um 00:16:
Bernhard,
Thank you for taking the trouble to reply. From the recommentation in
your first reply I got VueScan and followed the instructions to lock
exposure and film base colour. Along with film colour profiles this
has given much better results for most of the films I have scanned
and, in many cases, more natural looking colours than the lab that had
originally produced prints for some of the films concerned.
Given that VueScan can save raw TIFFs I made sure that option was on
so I can go back and try other options if necessary long after I have
returned the scanner. In the case of one film VueScan did not have an
exact profile and the closest similar one is definitely not right.
Following your latest e-mail I tried importing the raw files into
darktable and the invert module seems to do a reasonable job on them.
I do now wonder if part of the problem I was originally having was at
least due to auto-exposure on the scanner, i.e. exposure not locked
for the whole film. When working in darktable I was looking to get
the colours mostly right by working on one image and pasting the
history stack to the other images but what worked on one image was
wrong on others.
Thanks,
Steve.
On 22 November 2014 at 01:15, Bernhard wrote:
I just did some tests with some RAW TIFFs I created from my
scanner using vuescan and imported them to darktable.
I attach a sample file for you. This has room for improvements but
doesn't look so bad.
http://up.picr.de/20188260fw.jpg
No target, just use the invert module to get the orange mask
correctly, create a base curve, and doing white balance by using
the R-G-B-Sliders instead of color temperatur or the picker.
regards
Bernhard
Bernhard schrieb am 17.11.2014 um 20:02:
I use this workflow
https://web.archive.org/web/20080421211129/http://privat.albicker.org/foto-tutorials/foto-tut-neg-en.html
-Bernhard-
Steven Fosdick schrieb am 17.11.2014 um 19:18:
I have been using Darktable for some now for digital pictures
but I recently borrowed a slide/negative scanner and used it to
scan some old negatives I had. While searching I also
discovered a couple of rolls of undeveloped film from years back
which I got developed.
Looking at the colours from the negatives they seemed a little
odd but when I got the recently discovered films back from
developing complete with CD scans from the developer these have
turned out to have very different colours from those I get if I
scan the same negatives myself.
Here an example:
http://s16.postimg.org/tchwpmfwh/img22highres.jpg
This is the scan that came back from the people developing the film.
http://s16.postimg.org/l5pwy1ptt/img22raw.jpg
This is what I get if I scan the film myself.
I also have an example where water is a very obvious purple. As
I have already scanned quite a few images and had to return the
scanner, at least for the time being, I am wondering if can work
out a colour correction to be applied to the images from the
scanner I borrowed. Moving the sliders in the white balance or
colour balance modules to search for useful settings does not
seem to work very well. Taking samples from patches of what
should be the same colour on each of the scan from the
developers and the scan from the scanner I borrowed, working out
the ratio for each colour and then setting that as the gain in
the colour balance module works but only for that patch, i.e.
that patch then becomes the same colour in the corrected version
from my borrowed scanner and the scan from the developers but
the rest of the picture retains noticeably incorrectly coloured.
So this suggests to me that the film or some aspect of the
scanner does not respond linearly and the extent of the
non-linearity is different for each colour. This is presumably
what the other sliders in the colour balance module are intended
to correct but again moving them around whilst visually checking
is not very productive.
I know there is a step in adding a new camera to produce a
colour matrix which can be done given an IT8 target where there
are various shades of exactly known colours but I can't see a
way to do that in this case. IT8 targets do not seem to be
available on negative film and the films I have been scanning
are old so even buying an IT8 target, finding a film camera and
a similar roll of new film, photographing the target, developing
the film and then running the new camera colour matrix tool on
the resulting scan would not necessarily yield the right results
as the film formulation may have changed in the intervening
years (20 or more, in some cases).
Could a similar process work for multiple patches where for each
patch a sample (r,g,b) is taken from the desired colour and
another (r,g,b) for the uncorrected colour picking, for example,
both strong colours and neutral areas, shadows and highlights?
Does anyone know of a tool that would be able to process these
to work out the parameters for colour balance (or as a colour
matrix to add as if it was a new camera)?
If not what other approach would you use?
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Dashboards
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& more
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corporations, FREE
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--
regards
Bernhard
http://www.bilddateien.de
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