Colour grading a colour image to a reference colour chart, using Adobe Lightroom or Photoshop?

[Ares_der_Ruderer]

Hello all,

I have some colour pictures, that I would like to colour correct/grade, so that the colours match those found on a referance colour chart (please see attached picture). Does anyone know how I might be able to do this accurately (100% match colour to colour, not eyeballing with the sliders) using Lightroom, or normal photoshop ? Directing me a tutorial if one is not inclined to explain herein would also be more than welcome. Thank you in advance for any response

 

[Kino]

I would suggest 3D LUT Creator. You will have to figure out how to map each color chip to the perceptually closest color in a standard MacBeth Color Chip Chart, but it will then build a Look-up-table to map these colors to your image and it is compatible with Adobe Photoshop.

https://3dlutcreator.com/

They are having a Halloween Sale now; a good time to same some money if you decide to purchase the program.

Oh, and come back and show us your results! This looks like and interesting project!
What AGFA process does this emulate?

 

[Ares_der_Ruderer]

I would suggest 3D LUT Creator. You will have to figure out how to map each color chip to the perceptually closest color in a standard MacBeth Color Chip Chart, but it will then build a Look-up-table to map these colors to your image and it is compatible with Adobe Photoshop.

https://3dlutcreator.com/

They are having a Halloween Sale now; a good time to same some money if you decide to purchase the program.

Oh, and come back and show us your results! This looks like and interesting project!
What AGFA process does this emulate?

Thanks for the answer Kino. If I am understanding you correctly, within this 3D LUT Creator program, I will be able to match some of the colours of my referance chart to that of a digital MacBeth Color Chart situated within 3D LUT, which in turn will create a colour profile that will be able to be applied to pictures entered into the same program ?

As for the color chart I am looking to emulate, I am not entirely sure where its derrived from. I found it looking at resources around Autochrome-like plates made by Agfa, but I am under the impression that this chart does not reference this exact process, but is probably a general color chart used by Agfa to make corrections and arrive at what they perceived as desired colours.

 

[Alan Edward Klein]

Can someone explain why you would want this done? How does a program know what is the "correct" color?

 

[Ares_der_Ruderer]

Can someone explain why you would want this done? How does a program know what is the "correct" color?

I just want a program to automatically adjust the various colours in an image to match those of the colour chart. The result will hopefully be that the resultant colours of the picture will be rendered in a way that emulate Agfa Film.

 

[Alan Edward Klein]

How does it know which color is which?

 

[Ares_der_Ruderer]

How does it know which color is which?

I imagine using a picture that contains a colour chart to create the required adjustment profile, which could then be applied to the rest of the pictures. I do not imagine a program is yet capable of distinguising colours organically in the picture and correcting for them.

 

[grat]

A LUT is fundamentally, a lookup table (hence the name). Convert "this" color (by RGB/HSV/etc.) to "that" color (by RGB/HSV/etc). Most commonly used to convert from one photographic look to another.

This application will allow you to generate them pretty easily:

https://www.generator.iwltbap.com/

Create your "template" PNG (HALD), load it into an editor along with your images. Now edit colors, curves, etc., until you've got the image the way you want it to look, and save the altered PNG to a file. The generator will convert the PNG into a 3D LUT file that you can import to Affinity, Lightroom, Photoshop, etc..

There was a video for Affinity on how to convert an RGB image to resemble a Technicolor image-- I used that technique, created a LUT file, and now I can apply that LUT to any image to make it resemble an old Technicolor frame. Video editors can use that LUT to alter an entire video, if desired.

 

[Kino]

Thanks for the answer Kino. If I am understanding you correctly, within this 3D LUT Creator program, I will be able to match some of the colours of my referance chart to that of a digital MacBeth Color Chart situated within 3D LUT, which in turn will create a colour profile that will be able to be applied to pictures entered into the same program ?

More or less; it is simply a set of look up tables (like a spreadsheet for colors) that remap one color to another. The program doesn't have a MacBeth color chart inside it, but it does have a "standard response curve" for how colors should look in any give colors space, such as Adobe RGB or Rec. 709 (HD TV) or whatever.

It seems this guy has a tutorial on how to generate, save and apply a LUT in Photoshop:



See if that works for you.

As for the color chart I am looking to emulate, I am not entirely sure where its derrived from. I found it looking at resources around Autochrome-like plates made by Agfa, but I am under the impression that this chart does not reference this exact process, but is probably a general color chart used by Agfa to make corrections and arrive at what they perceived as desired colours.

Well, regardless of what Agfa wanted it to represent, it is a representation of the Agfa color space via the printing color space they used to reproduce it. It could only be exact if you had it printed onto a copy of actual film it was supposed to represent and that's not going to happen, so fake it!

In any regard, this sort of thing is easy to over-think. Try the above tutorial and see what happens...

 

[wiltw]

Use the 'do what I want' (DWIW) button of the program, to make colors automatically match what it has no idea what to match as a reference!

If your reference chart has provided 60 numerical R-G-B values for each of the color patches of the sample in OP, an automatic match becomes feasible. Otherwise, DWIW applies.

 

[grat]

Don't know if this is useful:

http://www.rags-int-inc.com/PhotoTechStuff/MacbethTarget/

 

[jtk]

Be aware that inkjet prints require a few minutes to settle before they give best color results...this varies with paper utilized.

 

[PerTulip]

Can someone explain why you would want this done? How does a program know what is the "correct" color?

Because you provide a reference. With digital, I use the X-Rite ColorChecker and the process is automated.

 

[Alan Edward Klein]

So my scanner an Epson 850 came with a reference chrome color chart that I scanned in. But I'm shooting and scanning different film, Velvia 50 let's say. Shouldn't I have to shoot a color chart with Velvia 50. Then scan it in as a reference chart somehow which then gets applied to all future Velvia 50 scans? And do that for each film I shoot?

 

[Kino]

Yes. A true color-managed work flow requires custom profiles for each film stock, the monitor used for evaluating/correcting and any printers/film recorders to be used.

Not many people outside of high-end professional services or media production companies have the resources to do this intensive profiling.

Just having a proper computer monitor that is calibrated to the color space you will be working in is a huge factor toward consistent image quality.

If you are posting to the web and sharing with friends, you can't control what they use to view your material, so a lot of the more fine-grained aspects of a color managed system are lost. Show me 5 computers with the same image displayed and I'll show you 5 different "looks"...

It's like going into the flat screen TV isle at any big box store and looking at all the variations from screen to screen. These are showing strictly color managed material and.. well, you know how uniform that looks. Even though production companies spend tens of millions of dollars establishing and maintaining color managed workflows, someone with a remote control and few minutes can defeat all of that very quickly.

It is so bad, there is a push to establish a "filmmaker's mode" standard setting for TVs to try to preserve the intent of the creators that will bypass all the "creative" adjustments a user or manufacturer can impose on their carefully crafted images: https://www.hollywoodreporter.com/m...dorse-filmmaker-mode-setting-new-tvs-1267374/

Strict color standards are only good in closed-loop system for fine tonal graduation and color; outside that, it's a crap shoot.

However, if you have at least a good monitor that is profiled properly for the color space you will be working in, you stand a better chance of looking good on a well calibrated monitor "in the wild".

A good free color display calibration software package is DisplayCAL at: https://displaycal.net/

The document section has valuable information on color profiling a monitor, but be forewarned, it's a very tough subject and gets wildly complex real quick.

My 2 cents...

 

[jtk]

For many the whole point is to inkjet print. While inkjet papers may vary, if one gets to know a few favorites that can establish solid predictability.