Custom made DCP Profile

Hi Nate,

I was experimenting a bit with custom made dual illuminant DCP profiles (COVID-19 lockdown you know…) using the following link :
[https://rawpedia.rawtherapee.com/How_to_create_DCP_color_profiles#Creating_DCP_profiles_using_DCamProf](http://How to Create DCP Color Profiles)

I have gotten satisfying results in my testing but while I was compiling the DCP I have noticed that the last lines of code in the DCP’s provided with NLP are slightly different :

    <ToneCurve Size="2">
    <Element N="0" h="0.000000" v="0.000000"/>
    <Element N="1" h="1.000000" v="1.000000"/>
  </ToneCurve>
  <ProfileCalibrationSignature>com.adobe</ProfileCalibrationSignature>
  <UniqueCameraModelRestriction>Fujifilm X-E3</UniqueCameraModelRestriction>
  <ProfileLookTableEncoding>0</ProfileLookTableEncoding>
  <BaselineExposureOffset>0.000000</BaselineExposureOffset>
  <DefaultBlackRender>1</DefaultBlackRender>

So my first question is, out of curiosity, how are you generating the DCP distributed with NLP ?
And second, what would be the recommended workflow/tool in order to create custom made DCP that are tailored for NLP ?

Last question : What is the BW settings used, or the master profile used when switching to BW ?

Thanks,

Raphael

Why not just use the included Negative Lab Pro profiles? I guarantee you that your time will be better spent working on improving your understanding on using the color correction tools in NLP then trying to redo the camera profiles…

All instructions you will find for making custom DCP profiles will be from the perspective of making profiles for digital positive photos. As such, there are a usually a number of things included in the profile that will have unintended, harmful consequences when working with negative scanning.

Examples of things that are made for digital camera profiles that will be harmful for negative scanning:

  • Embedded tone curves (that aren’t linear)
  • Lookup Tables designed for positive digital images (with things like hue twists, or optimizations for skin tones, etc)
  • Black rendering compensation (since it assumes the darkest areas in your capture are black, which isn’t true when working against the original negative capture).
  • Dual-illuminant profiles also pose additional considerations, since we’re correction for orange mask and not necessarily a scene illuminant.

Like I said though, I think you will find your time better spent working on improving your understanding of color correction in Negative Lab Pro.

Cheers,
-Nate

Hi Nate,

Thanks for the answer.

I have been using NLP since 1.3.1 and don’t get me wrong, it is fantastic ! I have been playing a lot with the different presets and sliders. The colour rendering is far down the list of things that frustrates me.

I was just trying to understand the science behind it and how things were working in the background as I know a lot about colour science on the printing side but only a little on the photo/software side.

Anyway, thanks for the explanation I will stick to what NLP is provided with and keep my Dual Illuminant profile for other purposes.

Cheers,

Raphael