Project

General

Profile

Bug #11620

can't create HDR

Added by benjamin chen almost 3 years ago. Updated almost 3 years ago.

Status:
New
Priority:
Low
Assignee:
-
Category:
Lighttable
Target version:
-
Start date:
05/21/2017
Due date:
% Done:

0%

Estimated time:
Affected Version:
2.2.4
System:
Ubuntu
bitness:
64-bit
hardware architecture:
amd64/x86

Description

Ubuntu 16.04, Darktable 2.2.4. Try to create HDR from a single raw file CR2, the resulting dng file is very magenta.

The resulting file exceeds upload limit, so I didn't upload. But it is very easy to reproduce.

Before upgrade, I ran 2.0.3, which creates HDR fine.

IMG_9149.CR2 (24.2 MB) IMG_9149.CR2 benjamin chen, 05/23/2017 12:53 AM

History

#1 Updated by Tobias Ellinghaus almost 3 years ago

I don't see a point in turning a single image into an HDR. What are you trying to achieve with that?

#2 Updated by benjamin chen almost 3 years ago

Tobias Ellinghaus wrote:

I don't see a point in turning a single image into an HDR. What are you trying to achieve with that?

Hi Tobias,
Thanks for looking into this.
raw file contains 12 bit data, which exceeds LDR presentation of an image, such as jpg. A raw file essentially is itself a HDR image. In this case, Darktable uses sophisticated Durand algorithm to tonemap to LDR.
I believe many people use single raw as source to get HDR tonemapped LDR image. I do not know the inner work of this tonemapping, but as a user, HDR tonemapping takes advantage of human eye localized perception to map the HDR to LDR. It will be sad to loose this function in Darktable.
Thanks.

#3 Updated by Roman Lebedev almost 3 years ago

benjamin chen wrote:

Tobias Ellinghaus wrote:

I don't see a point in turning a single image into an HDR. What are you trying to achieve with that?

Hi Tobias,
Thanks for looking into this.

raw file contains 12 bit data, which exceeds LDR presentation of an image, such as jpg.

Yes, that is why it's a raw file.

A raw file essentially is itself a HDR image.

Even ignoring for a moment that this is rather ignorant,

In this case, Darktable uses sophisticated Durand algorithm to tonemap to LDR.

there isn't any need to use "create hdr" function on a single raw (it's a NOP in such a case), you can already run tonemapping modules on a single raw.
Though the results vary greatly, to say the least../

I believe many people use single raw as source to get HDR tonemapped LDR image. I do not know the inner work of this tonemapping, but as a user, HDR tonemapping takes advantage of human eye localized perception to map the HDR to LDR. It will be sad to loose this function in Darktable.
Thanks.

Back to the subject. Without the sample, there isn't much to be done here.
At least upload that original single CR2.

#4 Updated by benjamin chen almost 3 years ago

Thanks. Here is one I got almost all magenta.
It is great that Darktable has its non-destructive processing.

Also available in: Atom PDF

Go to top