[Darktable-users] Nikon Picture Control (re:White Balance)

[o***@kefren.be]

Hi guys,

I've been doing some more digging about this issue and I think I've
figured out why the embedded JPEGs (or JPEGs in general) have settings I
can't seem to copy manually in darktable (mostly visible in white balance
& tints).

It seems (semi recent) Nikon camera's apply a 'Picture Control' to the
images that determine how the final rendered image will appear. ViewNX
(Nikon's free RAW converter) knows this & uses this to generate JPEGs that
are identical to the JPEG files generated by the camera, but software that
is unaware of these fail to copy these settings.

A similar issue exists in Lightroom
(http://photographylife.com/how-to-get-accurate-nikon-colors-in-lightroom)
and while this usually isn't really an issue (DarkTable tends to do an
excellent job at White Balance), sometimes the camera does it better than
I can.

The solution thus would be to figure out what those Picture Controls do &
how to apply these things in DarkTable.

http://imaging.nikon.com/lineup/microsite/picturecontrol/

Cheers

[Pascal Obry]

Post by o***@kefren.be
Hi guys,

...

Post by o***@kefren.be
A similar issue exists in Lightroom

Sure.

Post by o***@kefren.be
(http://photographylife.com/how-to-get-accurate-nikon-colors-in-lightroom)
and while this usually isn't really an issue (DarkTable tends to do an
excellent job at White Balance), sometimes the camera does it better than
I can.
The solution thus would be to figure out what those Picture Controls do &
how to apply these things in DarkTable.

I don't think that's feasible. For obvious reasons there is no way to access the
picture control setting from nikon. This is protected and even if we could get
some information there is probably zero chance to be able to apply consistently
setting in darktable to have *all* images looks like the Jpeg from the camera.

The internal circuitry to produce a Jpeg out of a RAW is was to complex to
get the same results. This is why the lr to dt import I've been working on
for darktable isn't 100% equivalent (and by very far for some images).

That's also why we have different image processing software like lr, dxo..
giving different output. Only ViewNX does the same job as it uses the
very same software as the one embedded into the camera.

All in all, what you are expecting isn't possible.

Regards,
Pascal.

[o***@kefren.be]

Hi,

Post by Pascal Obry
That's also why we have different image processing software like lr, dxo..
giving different output. Only ViewNX does the same job as it uses the
very same software as the one embedded into the camera.

For LightRoom it seems Adobe reverse engineered these Picture Controls the
hard way, with color charts etc but they do not apply them by default
(lack of confidence in their quality? Oversight?)

Post by Pascal Obry
All in all, what you are expecting isn't possible.

It might be impossible but understanding what they do would help to know
where I keep screwing up trying to recreate the look ;)

[Markus Jung]

Post by o***@kefren.be
Hi guys,
I've been doing some more digging about this issue and I think I've
figured out why the embedded JPEGs (or JPEGs in general) have settings I
can't seem to copy manually in darktable (mostly visible in white balance
& tints).
It seems (semi recent) Nikon camera's apply a 'Picture Control' to the
images that determine how the final rendered image will appear. ViewNX
(Nikon's free RAW converter) knows this & uses this to generate JPEGs that
are identical to the JPEG files generated by the camera, but software that
is unaware of these fail to copy these settings.
A similar issue exists in Lightroom
(http://photographylife.com/how-to-get-accurate-nikon-colors-in-lightroom)
and while this usually isn't really an issue (DarkTable tends to do an
excellent job at White Balance), sometimes the camera does it better than
I can.
The solution thus would be to figure out what those Picture Controls do &
how to apply these things in DarkTable.

IMHO, this is not an issue. If you want image looking like the OOC
JPEGs, use the OOC JPEGs. Developing your RAWs by yourself means making
the image look like you want it, not what your camera does. And this
implies the need to invest some time because this work has to be done
manually.
And you can not expect two different RAW developers to provide the same
results, this ist simply not how it works because every one has some
different algorithms, special features and sometimes, secret tricks.

Something regarding the whitebalance topic: By default, darktable
applies the whitebalance guessed by the camera (this information is
encoded in the RAW file). And as far as i experienced, this mechanism
worked quite well. You most likely want to have a look at some modules
in the color category, and play around with saturations and color tints.

Regards,
Markus

[o***@kefren.be]

I've read the manual (and eBook) but it didn't help me that much, the
problem is that I have zero experience in any of this and even though
I've
figured out some things the overall theory behind any of it eludes me.
I've considered getting a LR related book in the hopes that the theory
in
that translates over to DT but I'm not sure.

I do't think so, because the UI of darktable is somehow oriented at the
technical aspects of the algorithms/filters available there, i think LR
is designed to be more user friendly.

Well, it doesn't have to be LR, I can't run those apps anyway :)

On the other hand, the basics behind the scenes aren't that difficult.
You should have some idea about a few color spaces (RGB, HSV and a bit
Lab) that might be sufficient for starters.

The only one in that list that I'm familiar with is RGB so yea, anything
would be an improvement ;)

[Markus Jung]

Post by o***@kefren.be

On the other hand, the basics behind the scenes aren't that difficult.
You should have some idea about a few color spaces (RGB, HSV and a bit
Lab) that might be sufficient for starters.

The only one in that list that I'm familiar with is RGB so yea, anything
would be an improvement ;)

It isn't that difficult:

HSV/HSL splits the color information into three channels: Hue,
saturation and lightness/value. This way you can easly change the
saturation, hue or lightness without influencing the other two channels,
contrary to RGB. Many of the modules in the color section provide such
operations.
http://en.wikipedia.org/wiki/HSL_and_HSV

Lab is another color space which splits the information into a lightness
channel and two color channels, one for the blue-yellow part and the
other for the green-magenta part.

For the image editing part, thinking of colors in a HSV/HSL way can
often be helpful, i mentioned Lab because it is used internally in
darktable, some modules like the tone curve work in this color space.

Regards,
Markus