missing feature: invert colors (for scanned negatives)

[Beep6581]

Originally reported on Google Code with ID 1275

Its my fist time I fill a bug report, so please be calm if I did any mistake! 

I found the program unusable for editing scans of (analog) negatives caused by the
fact that there is no option to invert the photos. I would be happy if that could be
fixed with the next version.

System: Ubuntu 11.10 64bit Rawtherepee installed from the repositories. 

Branch: branch_3.0
Version: 3.0.0
Changeset: f375835d4ed1
Compiler: GCC 4.6.1
Processor: undefined
System: Linux
Bit depth: 64 bits
Gtkmm: V2.24.2
Build type: Release
Build flags: -g -O2
Link flags:  -Wl,-Bsymbolic-functions
OpenMP support: ON
MMAP support: ON
Rawzor support: OFF

Reported by raubwaldy on 2012-03-12 19:15:04

[Beep6581]

Hint: set tone curve to Custom and invert the curve

Reported by michaelezra000 on 2012-03-12 19:33:26

[Beep6581]

Reported by entertheyoni on 2012-03-12 21:50:34

• Status changed: Invalid
• Labels added: Type-Enhancement, Component-UI
• Labels removed: Type-Defect

[Beep6581]

Can this item be changed to an important valuable request?  I tried using the inverted
curves to process a negative image and it is very problematic.  All the functions operate
in reverse and I could not get the image to process without loosing data in the highlights
or shadows... (the program is designed to work on positives in subtle and not so subtle
ways) I did find a workaround though.  What I do is process the image as neutral and
only invert the colors nothing else then I save it as a 16 bit TIFF.  Next I open the
image from the TIFF file and process it the way I want...seems to work, but very cumbersome.
 What I suggest is adding a very simple conversion in the "preprocessing tab", a check
box which inverts the color values before any other steps so the program is working
on a positive from the beginning.

Reported by soccerdadphotos@yahoo.ca on 2014-01-10 00:56:50

[Beep6581]

yes, *please* add the ability to invert early in the workflow. I'm trying to process
hundreds of negatives I've digitized using my Nikon D70, and it would be awesome to
have this.

Please!

Reported by urban@unix-beratung.de on 2015-01-07 06:48:07

[Beep6581]

In the meantime I have tested using a CLUT to convert a negative to a positive, and
while indeed this produces a positive image, as soccerda noted above, all the exposure
controls operate in reverse, and I'm guessing all sorts of functions such as those
involving highlighting no longer work correctly.

Is it possible to implement an invert function such that the exposure controls would
work as designed after inverting?

Aren't such problems inherent to any use of a CLUT, and not just when inverting?

Reported by urban@unix-beratung.de on 2015-01-08 03:04:20

[Beep6581]

https://code.google.com/p/rawtherapee/issues/detail?id=2193

Sadly the work stalled and nobody had the motivation to continue :(

I had the impression that the negative clut would do the job but it looks like it is
not as early as needed and we need to use inverted settings also :(

A better option is to open the adobe standard profile and invert the tone curve

Reported by iliasgiarimis on 2015-01-08 03:41:33

• Status changed: Duplicate
• Merged into: #2177

---

• Attachment: [Nikon D70 inverted.dcp](https://storage.googleapis.com/google-code-attachments/rawtherapee/issue-1275/comment-6/Nikon D70 inverted.dcp)

[Beep6581]

Please upload a sample file of a negative to http://filebin.net/ or somewhere and share
the link here.

Reported by entertheyoni on 2015-01-10 23:15:38

[Beep6581]

I started a RawPedia page for processing negatives, please expand (don't worry about
poor English, I can revise):
http://rawpedia.rawtherapee.com/Negative

As I don't actually have any such files to test it on, the article is short :)

Reported by entertheyoni on 2015-01-10 23:54:12

[Beep6581]

Hi Folks,

you can find 3 scans of negatives here:

http://www.spielwiese.de/rob/Rawtherapee/

Rob

Reported by urban@unix-beratung.de on 2015-01-11 00:27:21

[Beep6581]

Thanks Rob! May I put them in our public test image folder?

Reported by entertheyoni on 2015-01-11 14:00:40

[Beep6581]

Hi entertheyoni,

feel free to put the images in the test folder.

Thanks for asking.

cheers,

Rob

Reported by urban@unix-beratung.de on 2015-01-13 00:43:30

[Beep6581]

Thank you, uploaded to http://rawtherapee.com/shared/test_images/ as negative_scan_rob_#.nef
I can replace "rob" with something else if you like, as long as its not long.

Reported by entertheyoni on 2015-01-13 01:22:11

[Beep6581]

yes, please replace "rob" with something. thanks.

Rob

Reported by urban@unix-beratung.de on 2015-01-13 01:33:44