Ciecam and Rawtherapee

Ciecam in Rawtherapee

A few weeks ago, I was reading an article in the French Photographic press about RT, here are its main conclusions.

  • performances and functionalities are equal to those of the top players on the market
  • the “advanced tab” contains 3 products - « Wavelet levels », « Retinex », « Ciecam » - we didn’t find what they could be used for.

If, for « wavelet levels », an answer has been brought recently, in particular by updating the documentation on Rawpedia, as well as by the videos provided by @Andy_Astbury1

https://rawpedia.rawtherapee.com/Wavelet_Levels, it is not the same for Ciecam.

I will develop in several points some information on « Ciecam and Rawtherapee »

  • what it’s for ?
  • what is it ?
  • where is it located in the process and what is its role in colorimetry?

What it’s for ?

I will take 6 examples - of course not exhaustive - to answer this question :

  1. We are going to process a high dynamic range image with heavily underexposed areas . We will use Ciecam to modify the Source lighting
    https://rawpedia.rawtherapee.com/CIECAM02#Example_1_.28Advanced_Tab.29
  2. Starting with an almost perfect white balance, we will use Ciecam to carry out a chromatic adaptation
    https://rawpedia.rawtherapee.com/CIECAM02#Example_2_-_Chromatic_adaptation
  3. We will show the impact of the output device and its environment (using a holiday shot to be viewed on the family TV in the afternoon). https://rawpedia.rawtherapee.com/CIECAM02#Example_3_-_Observation_conditions
  4. We are going to process a high dynamic range image, using “Local adjustments” (full image), « Log encoding + Ciecam »
    https://rawpedia.rawtherapee.com/Local_controls#High_dynamic_range_image_.2B_Ciecam
  5. We are going to make a “Dodge and burn” using using “Local adjustments”, Log Encoding and ciecam https://rawpedia.rawtherapee.com/CIECAM02#Example_5_.28Local_Tab.29_-_Dodge_and_Burn
  6. we will use an abstract profile in combination with Ciecam (under development)

What is it ?

https://rawpedia.rawtherapee.com/CIECAM02#Color_Appearance_.26_Lighting_.28CIECAM02.29_and_Log_encoding_modules

Where is it located in the process and what is its role in colorimetry?

https://rawpedia.rawtherapee.com/Toolchain_Pipeline

jacques

7 Likes

Great to see more documentation. I just yesterday noticed the amount of local adjustments info in rawpedia. Tested a difficult back lit image with good results.

One comment. I think the output concept should result in rethinking/tweaking the Rawtherapee ui and workflow with regards to export. Currently if you adjust an image for a new output you loose your previous settings. For me thats already a limitation of Rawtherapee.

The solution would be to either allow for “virtual” copies or the ability to assign export styles like ART. Saving and loading custom pp3 works but is a bit clumsy and complicated.

@jdc Superbe travail et toujours aussi ciselé et pédagogique. Merci

3 Likes

Sounds like a case of lazy journalism.

I love ciecam, though mostly use it in creative fashion - leaving the ‘scene’ and ‘viewing’ conditions in a neutral fashion (no visible effect on image), and playing with the ‘image adjustments’.

2 Likes