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Bug #11867

Externsion .hdr darker than .exr

Added by Diego Cesar over 1 year ago. Updated over 1 year ago.

Status:
Fixed
Priority:
Low
Assignee:
-
Category:
-
Target version:
Start date:
12/18/2017
Due date:
% Done:

100%

Affected Version:
2.2.5
System:
all
bitness:
64-bit
hardware architecture:
amd64/x86

Description

Hi,

I created two HDR images via Luminance HDR using the same input files, one I saved in ".exr" format and the other in ".hdr". However, the ".hdr" image is much darker than the ".exr" on darktable.

When I open them in Luminance HDR, both look like the same. I only notice this difference on darktable.

Sorry if it's a know issue or if it is not an issue at all.

I attached two screenshots showing the problem

sample2.png (378 KB) Diego Cesar, 12/18/2017 07:29 PM

sample1.png (1.03 MB) Diego Cesar, 12/18/2017 07:29 PM

Associated revisions

Revision ac3b9bda
Added by Tobias Ellinghaus over 1 year ago

Read primaries + wp from .hdr files

... so that colorin can use those values. Before it defaulted to sRGB
which was silly.
Fixes #11867

History

#1 Updated by Tobias Ellinghaus over 1 year ago

What are the input profiles set to for the two images in darktable?

#2 Updated by Diego Cesar over 1 year ago

For the ".exr" the input color profile is "embedded matrix" while for the ".hdr" the output is "sRGB (e.g. JPG)". I've played around with the input color profiles on ".hdr" but there is no option to make it look better.

Here is the link containing the .exr and .hdr files if you want to have a better look. -> https://we.tl/y5nXAsOWTJ

Regards,
Diego

#3 Updated by Tobias Ellinghaus over 1 year ago

I had a look at the .hdr file. It seems that PFStools omitted the Primaries header entry so darktable has no clue what the numbers mean. I am not sure if darktable would actually use the numbers if they were there, but like this there is nothing we can do.

Edit: Actually, the .hdr specs say that there are default primaries to use in that case. I will have a look.

#4 Updated by Tobias Ellinghaus over 1 year ago

  • System changed from Ubuntu to all
  • Status changed from New to Fixed
  • % Done changed from 0 to 100
  • Target version set to 2.4.0

I just added support for embedded primaries in .hdr files, and default values that follow the spec. Without that dt used sRGB for .hdr files which is a bad idea.

Even with that your sample file is still really dark. You will have to boost exposure and adjust black in the exposure module. That will bring you to the same state as the EXR.

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