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Would like to apply a Portra 400 or lomograph color grading filter to a digital photograph. Do these exist in the Darktable software for use in batch lighttable editing? If not, what is a similar solution

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3 Answers 3

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Color Look Up Table (different than the LUT 3D module and Velvia module referenced in the other answers) is the Darktable module that has film emulation presets for Fuji Astia, Fuji Provia and Fuji Velvia.

enter image description here

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You can use a lookup table (LUT). From the Darktable 3.8 documentation on lut 3D (emphasis mine) (link thanks to @xiota):

Transform RGB values with a 3D LUT file.

A 3D LUT is a tridimensional table that is used to transform a given RGB value into another RGB value. It is normally used for film simulation and color grading.

...

LUTs are most commonly used in darktable for color grading or film look simulation. For this reason, by default, the module is placed after the filmic rgb module in the pixelpipe and should be applied to a neutral image (without first applying a specific look). While you can find hundreds of free LUTs on the internet, you should note that that not all of them are compatible with the darktable environment and workflow – incompatible LUTs will not produce the advertised look. To limit the risk, a color grading LUT should have been created to work with one of the available “application color spaces” (see below), for both the input and the output of the module.

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    \$\begingroup\$ so how to simulate a specific film stock using the 3d LUT file? \$\endgroup\$
    – user610620
    Commented Jan 30, 2022 at 0:31
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    \$\begingroup\$ @user610620 darktable only provides the module to apply them but does not provide any LUTs itself, so you need to get them separately. This article contains several links. For example the HaldCLUT package of RawTherapee contains LUTs for emulating lots of different film stocks. \$\endgroup\$
    – luator
    Commented Jan 31, 2022 at 9:54
  • \$\begingroup\$ just wondering, how does RawTherapee interweave with this Darktable LUT? \$\endgroup\$
    – user610620
    Commented Jan 31, 2022 at 12:59
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    \$\begingroup\$ @user610620 The LUTs are provided in a standardised format, that is not specific to a certain software. The LUTs I linked to just happen to be provided by the RawTherapee people but they can be used with any application that supports this type of LUTs. \$\endgroup\$
    – luator
    Commented Feb 1, 2022 at 11:49
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Darktable has a built in Velvia module.

The external site dtstyle.net has many prebuilt styles including film simulation. It has been around for a while.

Google search suggests there are additional third party libraries containing film styles such as t3mujinpack.

However, film simulation in digital files is more art than science. Film has non linear responses to light, responds to UV, and involves chemical reactions that vary with temperature and technique and human interventions during processing, scanning, and printing.

Which is to say that simulating film is only as good as a photographer thinks it is. Unless the data in the picture file is appropriate, film styles won't give desirable results.

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  • \$\begingroup\$ Oh yeah, forgot about that. How does the Velvia module relate to a pre-existing film stock. What exactly is Velvia module trying to accomplish or emulate? \$\endgroup\$
    – user610620
    Commented Jan 31, 2022 at 12:57
  • \$\begingroup\$ @user610620 Velvia is a film stock. \$\endgroup\$ Commented Jan 31, 2022 at 17:10

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