Help to create a set of "PIXLS.US" color LUTs ?

[afre (Alan)]

Urban Dictionary: HALD

[patdavid]

@David_Tschumperle

@patdavid, do you think we could set up a specific page on the PIXLS.US website to offer this pack of free CLUTs when it will be ready ?

Absolutely. Just let me know and we’ll put something together! (Roping in @paperdigits as well so he’s aware.)

[David_Tschumperle (G'MIC staff)]

@chaimav

A searchable website based on tags (i.e. warm, cool, grunge,
high contrast, soft, retro, film sim, etc…) where users can rate and download them.

Looks like the description of https://freshluts.com/

[Iain]

I’ve converted the presets from my ‘tone presets’ filter to CLUTs so I will remove the filter eventually.

Iain’s cluts.zip (5.0 MB)

I was also like to remind people about the Customise CLUT filter in the GMIC plug-in. You can make custom CLUTs with it.

[Hebustetram]

My modest contribution

Original (GMIC Sample Image Landscape)

1. Taiga

2)Prussian Blue

3. Dark Blues in Sunlight

4. Tarraco
   (Probably would look better on urban / industrial picture with bricks)

5. Cinematic Lady Bird

6. Sweet Bubblegum

7. Sweet Gelatto

[Hebustetram]

@David_Tschumperle if it helps I have also the HaldCLUTs

Taiga

PrussianBlue

Dark Blues in Sunlight

Tarraco

Cinematic Lady Bird

Sweet Bubblegum

Sweet Gelatto

[David_Tschumperle (G'MIC staff)]

Thanks @Iain and @Hebustetram.
Getting the CLUT directly is better, as I’m sure it gives the transformation for more colors.

I’ll add them in the pack!

[Hebustetram]

@CriticalConundrum

I think that having a mental deconstruction process helps to demystify LUTs

For that I would follow Iain´s recommendation so you can actually see the 3D representation of a LUT and how it changes when you change target values of your each of your sources points.

@Iain

I was also like to remind people about the Customise CLUT filter in the GMIC plug-in. You can make custom CLUTs with it.

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@CriticalConundrum

I’ve observed that LUTs can be thought of as two types of operations combined:

1. Curve operation (our bread and butter)
2. Color shift operation (H-H curves, split toning, saturation, vibrance)

Would this cover all the bases?

You can do any transformation of the color space as long as for each original value you have a single output value. You can do any transformation in any channel, mix channels or map a non-lineal gradient to one channel.

@CriticalConundrum

curves are limited to producing values of R as a function of R while 2. produces R as a function of RGB.

Although this would be the case for most “photographic” CLUT, a CLUT does not require that the transformation is done as a continuous function. You can go funky or abstract with discontinuous transformations or even discrete changes.

Often you would do multiples transformations masked to target certain ranges of hue, saturation or luminosity (e.g. saturated yellows, bluish shadows, increase contrast in greens) and probably keep whole areas of the colour space unchanged (e.g. preserve highlights or skin colours).

[CriticalConundrum (Cranberry Carborundum)]

Made a simple one using the Datacolor test image. You can get more from http://www.northlight-images.co.uk/printer-test-images/. I quite like the PDI test image as it showcases a few skin tones in the bottom row.

Original:

Edit:

[Iain]

Here’s something I’ve been working on that is a bit different. It’s a CLUT to create a skin tone mask. All of the skin tones are set to white and all of the non skin tones are set to black.

It’s still a work in progress.

[CriticalConundrum (Cranberry Carborundum)]

It would be interesting to compare the tones covered by this mask vs the tones defined as “skin tones” in Rawtherapee

[Hebustetram]

Another set from a few years ago created to play with the Uzbek architecture and street fotos of a wonderful trip

Original

8. Uzbek Bukhara

9. Uzbek Samarcande

10. Uzbek Marriage

[Hebustetram]

11. Cinematic Mexico

12. Night Spy
    Technically it is an inversion of colours + swap of blue and red channels + green channel mixed and curves darkening

[Iain]

My CLUT is made by taking the pixels from real skin tones and setting that tone in the CLUT. So it is bound to give a different result.

[David_Tschumperle (G'MIC staff)]

Time for a progress report :

• We now have 32 CLUTs available in the pack. 31 of them have been compressed and included in the G’MIC plug-in (filter Colors / Color Presets, category PIXLS.US). This is pretty cool, and already enough to be distributed as a “Pack”.

• The PseudoGrey CLUT cannot be lossy compressed without losing its pseudogrey property, so I didn’t include it in the plug-in (only compressed CLUTs can appear there). It’s not too bad as we also have a filter in G’MIC for converting images in B&W with pseudogreys.

• I’ve updated the web page, with even more example and the 31 CLUTs visible : https://gmic.eu/color_presets/pixlsus_sample_9.shtml#browse

• I can now generate a Pack of CLUTs, as a .zip file, containing:

  • The haldclut in .png format (all normalized to a 512x512 resolution, which means a 3D CLUT resolution of 64^3, which is already quite good).
  • The CLUTs in .cube format (Adobe ASCII format for storing CLUTs). It’s a crappy format, but I think some software can only read this. I’ve limited the CLUT size to 33^3 for the .cube files to avoid having huge files.

• What we have to do next :

  • Decide what license we should use to distribute the Pack of CLUTs. Creative Common CC BY-SA everyone ?
  • Write a README file to put in the .zip archive, maybe add also a montage of all CLUTs applied on a single image, just to have a quick look of what it does ?
  • Set up a web page on PIXLS.US where we can put the .zip file of the PACK

Any suggestion and help is welcome !

[Iain]

My Skin Tone CLUT doesn’t really function as well as I had intended. It’s meant to create a binary mask but I think there is some interpolation that means it outputs greys.

I really only posted it as an example of something you could do with a CLUT rather than something you should do with one. There’s no harm in leaving it in, but I don’t think it is really useful.

With regards to the license, I am happy for my CLUTs to be public domain, so anything more restrictive than that is fine by me.

[Iain]

Oh! I thought of something for the GMIC plug-in. In the ‘apply external CLUT’ it would be fun to be able to load two CLUTs and mix them together in different proportions before applying it.

[David_Tschumperle (G'MIC staff)]

OK, I’ll remove the “Skin Tones” CLUT from the Pack then.
Shades of grey are due both to the downsampling of the CLUT and the lossy compression.

[Hebustetram]

@David_Tschumperle

Decide what license we should use to distribute the Pack of CLUTs. Creative Common CC BY-SA everyone ?

Fine for my contributions.

[paperdigits (Mica)]

@David_Tschumperle

Creative Common CC BY-SA everyone ?

Just a reminds that by uploading them here without a license, they assume a CC license.