Rawtherapee Processing Challenge feedback

Rawtherapee Processing Challenge feedback

Chapters :

• 1) Introduction - Who this document is for ?
• 2) The images
• 3) How do you approach this problem? The how.
• 4) The new features tested in this challenge
• 5) Rawtherapee processing and interface
• 6) The impact of RT's internal design - the pipeline
• 7) A possible answer to why? Testers' comments.
• 8) Some conceptual elements in systemics and sociology
• 9) How might Rawpedia evolve? Some systemic concepts.

Introduction - Who this document is for ?

This Feedback Report (Retour d'Expériences : « Rex » in french) was produced for the Rawtherapee Processing Challenge, which took place in March and April 2024. The aim of this challenge was twofold: a) to allow you to familiarise yourself with Cam16 and the tools that have been integrated into the Local Adjustments "Color appearance (CAM16 & JzCzHz)" module. b) to validate the changes before merging into "dev". This feedback, « Rex », can help you to better understand Rawtherapee, its architecture and its tools, and to improve the quality of your images as quickly as possible by benefiting from the experience of others.

Who this document is for ? The target audience is anyone with an interest in image processing (I'm excluding the absolute beginner, as he or she doesn't have the minimum knowledge required to get started): beginners or experienced users, experts or not, amateur or professional photographers, developers, algorithm designers, and so on.

The images

We have chosen 6 images that are already well known on the forums. They are all 'difficult' in that simple processing is rarely satisfactory. Brief characteristics of these images, which will have a major impact on processing:

• IMG_0080.CR2: sunset, underexposed image, digital noise, high dynamic range 12 Ev.
• 2010_MONTR_033.NEF: "The blue horse". Shaded and sunlit areas, deep whites and blacks, isolated green tree, sky reduced to a small part of the image. In the centre the horse, its blue reflection and the carriage.
• S7_00463.ARW: Very under-exposed background framing the dance scene, artificial lighting, digital noise, high dynamic range 16Ev.
• B.dng: isolated house in the countryside, overall dull appearance, lack of contrast (dynamic) and color.
• IMGP2426.DNG: sunset, strong under-exposure to 'keep the sun', high Dynamic 14Ev.
• 2024-03-22_14-28-41.75_DSC5286.NEF - Quantum of the seas - blur - low contrast.

I have added 2 images outside the "Challenge" because they were cited for Cam16's use :

• hagalund-test01.DNG - Smooth highlights example,
• Sweep-sRGB_Linear_Half_Zip.tif , for Dynamic Range of 25Ev.

All these images are CC BY-NC-SA 4.0

How do you approach this problem? The how

The 6 images were processed by people with different experience. I'll leave it to you to discover - there's no "right solution" - how each of the testers treated the images. You'll be able to get ‘how and why they did ?’, and I hope to benefit from their experience to help us improve.

I've attached the 6 images. For each:

• the Raw file ;
• the thumbnail of the image as it appears unprocessed - on the left ;
• a thumbnail preview of what can be achieved - right;
• all the pp3 files - on the left, with a very brief summary of 'how' the tester did each one - on the right.

In a few cases, you'll see a 'pp3' ending in 'jd'. As part of the 'why', I have added one or two additional 'Local adjustments' to an existing treatment (arbitrary choice) for educational purposes.