darktable ep 082 - Color Calibration module (pt 1 of 2 - channel mixer)
Summary
TLDRIn episode 82 of 'Understanding Darktable', the focus is on the new color calibration module in Darktable 3.4, which replaces the deprecated channel mixer and supplements the legacy white balance module. The video explains the module's dual role and its settings, including the auto-apply chromatic adaptation defaults in preferences. It covers the use of color calibration as a channel mixer, detailing the interface updates, the concept of camera reference (D65), and the process of adjusting color channels for various effects. The episode also touches on presets for monochrome mixes, suggesting they provide a more accurate representation of film stocks. Part two will explore the module's use as a white balance supplement.
Takeaways
- 🔄 Darktable 3.4 introduces a new module called 'Color Calibration' which replaces the deprecated 'Channel Mixer' module and supplements the 'Legacy White Balance' module.
- 🎨 The 'Color Calibration' module has two functionalities: as a replacement for the 'Channel Mixer' and as an addition to the 'Legacy White Balance'.
- 🛠 In the preferences, there's a new setting 'Auto Apply Chromatic Adaptation Defaults' which can be set to 'Legacy' or 'Modern', affecting how the 'Color Calibration' module is used upon importing or resetting images.
- 📸 The 'Legacy' setting applies the 'Legacy White Balance' module as usual, while 'Modern' activates the 'Color Calibration' module with a 'Camera Reference' setting, typically D65.
- 📚 The script suggests further reading on photo.net for those interested in the technical aspects of illuminance and chromatic adaptation.
- 🔄 The 'Color Calibration' module operates differently from the old 'Channel Mixer' by working in an unbounded color space, offering more flexibility with tones, colors, and hues.
- 🎛 The module features tabs for each color channel (R, G, B), allowing for adjustment of the output based on the input from other channels.
- 🌈 The 'Colorfulness' tab lets users adjust the intensity of the color channels, either accentuating or attenuating the effects made on the R, G, and B tabs.
- 🔆 The 'Brightness' tab alters the luminosity of each color channel, with options to make them darker or brighter.
- ⚫ The 'Gray' tab is used for creating monochrome mixes from color images, offering a way to blend primary channels into a black and white result.
- 📚 New presets for black and white film stocks have been created by Aurélien for the 'Color Calibration' module, which are believed to be more accurate than the old presets.
Q & A
What is the new module in Darktable 3.4 called?
-The new module in Darktable 3.4 is called 'Color Calibration'.
What are the two main functions of the Color Calibration module?
-The Color Calibration module serves two main functions: it replaces the deprecated Channel Mixer module and acts as a supplement to the legacy White Balance module.
What is the 'auto apply chromatic adaptation' setting in Darktable preferences?
-The 'auto apply chromatic adaptation' setting in Darktable preferences determines the default behavior for the Color Calibration module when importing a new image or resetting the history stack. It can be set to 'legacy' or 'modern'.
What does setting the 'auto apply chromatic adaptation' to 'legacy' do?
-Setting the 'auto apply chromatic adaptation' to 'legacy' means that the legacy White Balance module will be applied as usual, defaulting to the white balance set in the camera at the time of exposure, and the Color Calibration module will not be added to the list of active modules.
What happens when the 'auto apply chromatic adaptation' is set to 'modern'?
-When set to 'modern', the legacy White Balance module is set to 'camera reference' (usually D65), and the Color Calibration module is activated by default for all processing.
What does the 'Camera reference' setting in the White Balance module refer to?
-The 'Camera reference' setting in the White Balance module refers to a standard illuminant, usually D65, which is used as a reference point for white balance.
How does the Color Calibration module differ from the old Channel Mixer module?
-The Color Calibration module works in an unbounded color space throughout its part of the pixel pipe, allowing for more tones, colors, and hues to work with, unlike the old Channel Mixer which was assumed to work in an sRGB color space all the time.
What is the purpose of the 'Chromatic Adaptation Transform' tab in the Color Calibration module?
-The 'Chromatic Adaptation Transform' tab in the Color Calibration module is used to set the adaptation to none, essentially turning off this tab and removing all options except for the gamut compression when using the module as a channel mixer.
What does the 'Colorfulness' tab in the Color Calibration module allow you to do?
-The 'Colorfulness' tab allows you to accentuate or attenuate the intensity of any adjustments made on the R, G, and B tabs.
What is the 'Brightness' tab used for in the Color Calibration module?
-The 'Brightness' tab in the Color Calibration module is used to alter the intensity or luminosity of each of the red, green, and blue channels.
How can you create a monochrome mix of a color image using the Color Calibration module?
-You can create a monochrome mix of a color image by adjusting the sliders in the 'Gray' tab of the Color Calibration module to decide how much of each of the three primary channels you want to introduce into your monochrome mix.
What are the presets in the Color Calibration module for monochrome mixes based on?
-The presets in the Color Calibration module for monochrome mixes are based on film stocks, and they are designed to be more representative of the film stocks they are named after, according to the creator of the presets, Aurelian.
Why was the old Channel Mixer module deprecated in Darktable?
-The old Channel Mixer module was deprecated because it was assumed to work in an sRGB color space all the time, which is not necessarily the case in modern photography. The new Color Calibration module offers more flexibility by working in an unbounded color space.
How can you access the deprecated Channel Mixer module if you still want to use it?
-You can access the deprecated Channel Mixer module through the 'Modules Presets' window in Darktable, where there is a preset of grouped modules for deprecated modules.
Outlines
📚 Introduction to Darktable 3.4's Color Calibration Module
The video script introduces a new module in Darktable 3.4 called 'Color Calibration,' which serves dual purposes. It replaces the deprecated 'Channel Mixer' module and also complements the 'Legacy White Balance' module. The tutorial is split into two parts, with this first part focusing on using the new module as a channel mixer. The script also revisits the 'auto apply chromatic adaptation defaults' setting in preferences, explaining the 'legacy' and 'modern' options and their impact on image processing. The presenter sets the module to 'modern' for all processing, demonstrating the updated user interface for the white balance module and explaining the 'Camera Reference' setting, which is typically set to D65, a standard for daylight illumination.
🎨 Exploring the Color Calibration Module as a Channel Mixer
This section delves into using the Color Calibration module as a replacement for the old Channel Mixer. The module operates in an unbounded color space, offering more flexibility in color and tone adjustments than the deprecated Channel Mixer, which was limited to the sRGB color space. The presenter explains the functionality of the R, G, and B tabs, which control the output of the respective color channels, and how to adjust them to create custom mixes. Additionally, the 'Colorfulness' tab is introduced, which allows for accentuating or attenuating the intensity of the color channels. The 'Normalized Channels' checkbox is explained, which ensures consistent output saturation regardless of the input values. The summary also touches on the 'Brightness' tab for adjusting the luminosity of each channel and the 'Gray' tab for creating monochrome mixes, mentioning the new presets designed to better emulate film stocks.
🖤 Transitioning from Old Channel Mixer to the New Color Calibration Module
The final paragraph discusses the transition from the old Channel Mixer module to the new Color Calibration module. It mentions that the old module has been deprecated and is no longer readily available in the Darktable UI, but can still be accessed through a 'grouped modules for deprecated modules' preset if needed. The presenter recommends using the new Color Calibration module for channel mixing tasks moving forward. The video script concludes by previewing the next episode, which will cover using the Color Calibration module as a supplement to the Legacy White Balance module.
Mindmap
Keywords
💡Color Calibration Module
💡Channel Mixer
💡White Balance
💡Chromatic Adaptation Transform
💡Camera Reference
💡Scene Referred Workflow
💡Filmic and Exposure
💡Monochrome Mix
💡Presets
💡Normalized Channels
💡UI Refresh
Highlights
Darktable 3.4 introduces a new module called 'Color Calibration' with two distinct functionalities.
The Color Calibration module replaces the deprecated 'Channel Mixer' module.
It also serves as a supplement to the 'Legacy White Balance' module.
A new preference setting 'Auto Apply Chromatic Adaptation Defaults' is introduced for the Color Calibration module.
The 'Legacy' option in preferences will apply the Legacy White Balance module and not activate the Color Calibration module.
Choosing 'Modern' in preferences will activate the Color Calibration module and set the Legacy White Balance to 'Camera Reference'.
The 'Camera Reference' setting is typically set to D65, a standard for illuminance in photography.
The Color Calibration module can be used as a Channel Mixer by setting the adaptation to 'None'.
The module provides an unbounded color space, offering more tones, colors, and hues to work with compared to the old Channel Mixer.
Each color channel (R, G, B) can be independently adjusted to create custom mixes.
The 'Colorfulness' tab allows for accentuation or attenuation of the intensity of the color channels.
The 'Brightness' tab adjusts the luminosity of each color channel.
The 'Gray' tab is used for creating monochrome mixes from color images.
Aurelian has created new presets for the Color Calibration module that are more representative of film stocks.
The old Channel Mixer module can still be accessed through the 'Modules Presets' window for those who prefer it.
The Color Calibration module is recommended over the old Channel Mixer for current use.
The next episode will cover using the Color Calibration module as a supplement to the Legacy White Balance module.
Transcripts
dark table 3.4 has a new module called
color calibration and there's quite a
lot to cover
so again i'm going to break it up into
two episodes
this will be part one let's go
[Music]
hi and welcome to episode 82 of
understanding dark table
to my mind the color calibration module
has
two personalities on one hand
it replaces the now deprecated
channel mixer module so that's one
personality and
its other personality is as a supplement
to the legacy white balance module
in this episode we're just going to look
at the first of those two personalities
using the new color calibration module
as
a channel mixer now before we start
i do just quickly want to revisit for
the benefit of those people who've come
straight to this video without watching
the
dark table 3.4 new features videos
in the preferences
and under processing we now have a new
entry auto apply chromatic adaptation
defaults now this pertains
to the color calibration module
specifically the default option here
is legacy so when you first install
dark table this will be set to legacy
and what that means
is that when you either import a new
image
or reset the history stack
on an image you've already got in your
library
the what legacy white balance module
will be
applied as per usual
and it will default to whatever was
the white balance set in camera at the
time of exposure
the color calibration module will not
be added to your list of active modules
that's the legacy mode if you change
this to modern what you are saying to
dark table
is whenever i import a new image or
whenever i
reset the history on an image i've
already got in my library
i want you to set
the legacy white balance module to
a new option which we'll look at in just
a sec called camera
reference and i want you to
activate the color calibration module
and we'll go into that a little bit more
in episode 83 but i did just want to
cover it for anyone who
didn't watch the new features videos
okay so
as you can tell i have it set to modern
so i'm using the color calibration
module by default for all of my
processing from this point forward
so to use the color calibration module
as
a channel mixer i have chosen this image
of desiree that i shot a few years ago
and what i've done is simply hit the
reset parameters button in the history
stack
and as you can see all of the regular
things get applied
color calibration is turned on and
because i've got
a scene referred workflow set in
preferences as well
it also means filmic and exposure uh
set to active as well so that
is the image straight out of camera
now if we look at the active modules
we will see that the white balance
module has had a little bit of a ui
refresh with dark table 3.4
we now have these four icons one for the
white balance as shot in camera
one for set the white balance detected
from an area and if we click on that we
will get the
white rectangle that takes up 99 of the
frame
and so dark table will do its best to
read the white balance
from the image itself we then have
a user modified section where you can
set your
own color temperature if you have a
specific reason for wanting to do that
and then we have this new one camera
reference
point in most cases it should be d65
now i will confess that d65 is a
whole new language to me i went and did
a bunch of reading
and i kind of understood some of it and
sort of eyes glazed over for a lot of it
however i did find an interesting
discussion on photo.net and i will put a
link to that
in the description down below so if you
really want to get into the weeds on
illuminance
then by all means hit that link and go
and read up
some interesting stuff in there and i
probably need to go and revisit it
but just understand that if you choose
modern
as the preference for chromatic
adaptation transform
in preferences then this
legacy white balance module will be set
to
camera reference or d65 and then
the color calibration module will do its
thing
now on this first tab the
chromatic adaptation transform if we
want to use
the color calibration module as a
channel mixer
we basically want to set the adaptation
to none and that is basically then
just turning off this tab
essentially it's removing all of the
options that are there with the
exception of the gamut compression
and so now what we've got is an r
channel a g channel and a b
channel and they are your old now
deprecated
channel mixer now i don't fully
understand the reasons for why the old
channel mixer was deprecated i think it
was something to
do with the the science and the color
space in which it worked i think
it assumed that you were working in an
srgb
color space all of the time and
obviously
these days that's not necessarily the
case
and the color calibration module will
work
in an unbounded color space uh
throughout its little part of the pixel
pipe
and that basically means you've got
more tones and colors and hues and
things to work with
that's my understanding don't shoot me
if i'm wrong
okay so how does this work well
basically each of these tabs
so r for red g for green b for blue
represents the output of that particular
color channel
and by default the input values
to each of those outputs is red is at
one and green and blue are at zero
on the green channel the green input is
at one
red and blue are at zero and on the blue
channel the blue channel
is inputting at one and red and green
are inputting at zero
so the idea is that you can now create
any mix
for the output of the red channel simply
by
choosing to re-adjust the sliders now
i am not going to pretend to know how to
use this in an efficient manner because
i never used the channel mixer either i
understand
the concept but i just i recognize that
it's way too powerful at all for my
limited understanding
and i would probably do more damage than
good
if i was to muck around with it if you
want to reset these you can just double
click on the sliders
that's nothing new and that will set
everything back to default values you'll
then notice there is a colorful tab
a brightness tab and a grey tab
now the colorfulness tab
is there to allow you to either
accentuate or attenuate
the intensity of anything you did
on the rg and b tabs so for example if i
was to come and do
something absolutely horrendous here i
have no idea what i'm doing but let's
just say i had done this
as a new mix for my red channel
i could go to the colorfulness tab and
this
input red slider will allow me to turn
down the effect of that red channel or
crank up
the effect of that red channel and then
the same applies for
whatever you do on the green channel you
would you would then have the ability to
attenuate
or accentuate that green
channel output on this green slider here
and then the same for the blue channel
you'll notice at the bottom here a
checkbox for normalized channels if you
activate that then regardless of
what you might dial in across these
three sliders
all of those values will be summed
together
and then divided back to a
value of one so essentially
even though you might have numbers that
don't necessarily add up to 1.0
whatever values you have you know
applied across these three sliders
will be correlated against each other so
that the output saturation
is consistent with the input saturation
it's just that the channel
mix will be a little bit different
next up we've got the brightness tab i
am just going to reset
these and the brightness tab as the name
suggests
simply allows us to alter the intensity
or the luminosity of each of our
red green and blue channels so we can
make our red channel darker
or brighter we can make our green
channel darker
whoa that's funky uh or brighter
or our blue channel darker oh
it's like morticia uh or brighter and
again the normalized channels checkbox
is there
to basically average out whatever
values you may have entered across these
three sliders
to then basically end up with a value of
one across those three values so that
the
output luminosity hasn't changed from
the input luminosity
but the luminosity of the individual
channels has been skewed
from where it was at the input stage
hopefully that makes sense
and then finally we've got the gray tab
and this is where you will do your
monochrome mixes of color images
now the moment you move any of these
sliders
away from their default positions at the
far left
your image will basically go black and
it is then a case of
deciding how much of each of the
three primary channels you want to
introduce into your monochrome mix
now sure you can just drag the sliders
around and find what looks good for you
or you can check out the new presets
that aurelian has created here
he did mention in his video that he was
not
entirely happy with the black and white
presets that existed
in the old channel mixer module and he
did confess that he made those up
many years ago when he knew less than he
knows now
and he doesn't feel today
in early 2021 that
those presets were as accurate
as they should have been and he believes
that these new
presets that he's come up with for the
color calibration module
are far more representative of
the film stocks that they are named
after so
if you did use the old channel mixer
module
for some of your past processing
exploits it might be worth going back
and particularly if you were working off
raw files
create duplicates disable the channel
mixer
enable the color calibration module and
maybe try some of these presets and just
see whether or not
you feel that these presets are a better
representation of the black and white
film stock they're trying to emulate
than the presets which were in the old
channel mixer module
now we'll just mention because the old
channel mixer module has been deprecated
it means that you won't
naturally find that module
available in the ui of dark table
anymore
however if you did watch the videos on
new features you would have seen me
cover the new
modules presets window
and within there there is a preset
of grouped modules for deprecated
modules
so even if you do want to keep using the
channel mixer module
you can access it from there if you want
to
but i think the recommendation is if you
want to do channel mixing
trickery today avoid the old channel
mixer module
and go with the new color calibration
module
alrighty i am going to leave it there
for this episode and in episode 83
we will look at using the color
calibration module
as a supplement to the legacy white
balance module
looking forward to it all right catch
you in the next one
[Music]
you
Weitere ähnliche Videos ansehen
Better Colours for PC Gaming
Working with HLG / Sony Color Modes / Matching Picture Profiles - FAQ
Come controllare il colore con Darktable
Darktable 4.6 Beginners's Guide: Mastering Photo Editing for Beginners 📸
Color Grading 101 - Everything You Need to Know
LG 2021 OLED TV (C1, G1) Picture Settings Explained - Big Changes!
5.0 / 5 (0 votes)