Colour management advice needed - again!

[Tom Bussey]

I'm trying to develop a colour management policy for my company. It's an architectural practice, so just about everyone in the company probably couldn't care less, until something looks different in print to how it does on screen. Every time I approach this subject my head hurts and I shy away from it again, but I think I've more or less got my head around it now. Being that we're using Vray 5 which also appears to have proper colour management now too it seems sensible to push ahead with it. 

90% of what we do is for web but there are occasions we work for print. This is what seems sensible so far, please say if this is well off:
 

1. get x-rite calibration tool and create ICC profile for main monitor (BenQ PD3200q)
2. load this profile to the monitor in windows colour management
3. set working space in Photoshop to Adobe RGB
4. when exporting jpgs 'convert to sRGB' or convert to CMYK profile agreed with printer for print
5. Profile critical monitors of critical other teammates - not high gamut ones
6. Get them to use a colour managed photo viewer - They probably just tend to use the  Windows Photos app, which I understand isn't colour managed, but does this just assume sRGB anyway? Is there a better, free viewer that I could easily convince people to use to look at colour critical images (not everyone has Photoshop here).

What I don't understand is how to use the new colour space settings in Vray VFB2. Presumably if I use the sRGB profile, and AdobeRGB as my Photoshop working space, there will be differences, but does this even matter? maybe I should just use sRGB as my default working space, although this would clip some blues and greens from the CMYK gamut from what I understand? I did actually see the effect of this on a previous project where some very vivid greens appeared clipped when I exported to CMYK.

[James Vella]

Step 1 & 2 from your list look correct. From what I see of the specs of your benq this is 100% rec709/srgb, so it doesn't make sense to me that you are using the Adobe Color Profile when you cant see that gamut range.

 

For print you want to use the color profile from your printer for your Proof Setup in Photoshop. More on this in the 2 first links below regarding CMYK & RGB printers, printer profiling, monitor brightness & ink/paper variations.

 

For internal viewing I would just keep it in rec709/srgb for simplicity amongst staff, if they have color corrected monitors it will appear the same anyway. 

 

The sRGB profile in Vray is just a viewing transform to display the colors with the correct gamma for most standard output like web. When you output a render to .exr format you have a linear image with the widest possible gamut range so you are only limited by your compositing software, photoshop cannot interpret the full range (still does a good job for typical archviz however). With high end compositing software linear files can be interpreted and transformed at any stage in the pipeline to different color spaces. The new Vray frame buffer has made this viewing transform simpler but still requires a bit of know how to get the pipeline right (so you can see what the compositor can see basically). More on this in the 3rd link below - a bit more than you need in this simple situation but useful to read if you are interested in color theory and the ACES workflow. 

 

Adobe From Camera to Print:

A Color Managed Raw Workflow—From Camera to Final Print (adobe.com)

 

X-Rite Color Management Basics:

L11-144_CompleteGuideToColorManagement_EN.pdf (xritephoto.com)

 

Going down the rabbit hole (ACES):

Chapter 1: Color Management - Chris Brejon

Edited November 25, 2020 by James Vella

[Tom Bussey]

Ok, so as usual, when I start looking deeper in to this subject I fall down a rabbit hole and get more confused! Thanks for those links though, I'm slowly making my way through that Brejon article.

But just to stick with my original post for a minute.

 

Quote

 the specs of your benq this is 100% rec709/srgb

You're right! I think I was thinking of my monitor at home which is a bit better, supposedly. So yes, sRGB is going to be best, with the caveat that I'll lose a bit of the possible CMYK gamut for the occasions we do print work.

 

Quote

The sRGB profile in Vray is just a viewing transform to display the colors with the correct gamma for most standard output like web

Is this working in the same way as the working space in Photoshop? So if I have the VFB in sRGB mode and my working space in sRGB, they should appear exactly the same right?

If so that Brejon article seems to say that I shouldn't be using an sRGB display transform and that I should be using a tone mapping LUT in order that I don't get blown out highlights! But maybe I can't do that because Photoshop doesn't support OCIO!?

This is where my brain melts.

OCIO luts are probably overkill just for consistent colour between 1 producer (me) and a couple of other viewers in the office, but  the comparison images between an sRGB display and one with the spi-anim LUT certainly seems like something I should know about!

[James Vella]

2 hours ago, Tom Bussey said:

So yes, sRGB is going to be best, with the caveat that I'll lose a bit of the possible CMYK gamut for the occasions we do print work.

RGB encompasses CMYK so there should be no loss. Just make sure your printer is profiled like i mentioned above and you do the conversion process correctly. 

 

2 hours ago, Tom Bussey said:

Is this working in the same way as the working space in Photoshop? So if I have the VFB in sRGB mode and my working space in sRGB, they should appear exactly the same right?

Yes

2 hours ago, Tom Bussey said:

If so that Brejon article seems to say that I shouldn't be using an sRGB display transform and that I should be using a tone mapping LUT in order that I don't get blown out highlights! But maybe I can't do that because Photoshop doesn't support OCIO!?

The short version is - use sRGB if you don't do relighting outside of 3D or any archiving for future proofing (archiving is mostly required for film). 

LUT - This is just a look up table, it transfers color's in a table/matrix, its not a one stop shop to fix your highlights - in fact could make it worse. You can also use LUTs in Photoshop. Think of it like a curve adjustment.

OCIO - Open Color IO is a display transform. You can change the Input Color Space, Display Device and View Transform. This was typically how you would use ACES before Vray5, I haven't tested it in Vray5 so I don't know how it works but you can read the manual apparently its much easier now.  You can think of OCIO like a profile just like you use soft proofing in photoshop for print, there's a bit more to it but that's as simple as I can put it. This method is the highlight fix you are referring to but it helps to understand why, Brejon explains it well. 

LUT is not OCIO.

Photoshop uses ICC Profiles instead of OCIO, there is a hacky way to convert profiles to ICC but like I said before photoshop is not designed for this workflow and its more trouble than its worth. Its just easier to either use Affinity which also has a better 32bit support or just work in 16bit in photoshop and do your tone-mapping in the 3D frame buffer.

 

Vray Manual about ACES:

ACEScg Workflow Setup - V-Ray 5 for 3ds Max - Chaos Group Help

Edited November 25, 2020 by James Vella

[James Vella]

1 hour ago, Tom Bussey said:

OCIO luts are probably overkill just for consistent colour between 1 producer (me) and a couple of other viewers in the office, but  the comparison images between an sRGB display and one with the spi-anim LUT certainly seems like something I should know about!

Yes and yes, its good to learn about, I have an Adobe color calibrated monitor and I do all my work in RGB ?

Edited November 25, 2020 by James Vella

[Tom Bussey]

One more thing... What did you mean by this?

 

Quote

photoshop cannot interpret the full range

 

[James Vella]

You cannot work in a scene-linear workflow in photoshop - you have no proper viewing transform that goes beyond the simple gamma model. This isn't a bad thing however since tone mapping can produce a similar result and requires less technical knowledge from the artists perspective. There is a great paper on this well worth reading if you are interested.

 

Cinematic Color

The pdf at the top labelled Cinematic Color: From Your Monitor to the Big Screen (pdf, 6.6 MB)

Edited November 26, 2020 by James Vella

[James Vella]

To be completely honest I only know enough about this to be dangerous so take what I say with a grain of salt - you are better off reading the papers and studies of those in the film industry. Yes its confusing at first, some of it will make sense to you at a later point, some of it is probably not even useful to you at all in your current employment.

This is how I look at the ACES pipeline:

- Do you have the hardware/software required for this workflow?

- Do you produce work that is absolutely color critical?

- Do you have many artists working on different platforms which need to be harmonized for consistency in a non destructive manner?

- Does the work need to output to many different devices and look consistent, film, projectors, different display devices etc?

- Does the work need to be remastered at different intervals of time for new technology?

- Do you have a need for it?

If your answer for these questions is mostly no then I doubt you need to go down the rabbit hole unless its a personal interest or self education or some other factor.

 

Regarding your original question - If your first problem is consistency between monitors then you need to calibrate/profile your monitors. If second problem is print then the solution is simply profile the printer and use that as a proofing template in photoshop. 

 

If you want your work to look 'more realistic' there are many ways of going about it without having to go down the rabbit hole. Tone mapping is a very useful solution to this challenge currently and probably worth your time investigating if that's the case - especially with the new frame buffer in vray.

 

edit: Im doing some tests today with the new color management system acescg in vray5, ill post up some results later. It already looks like its much better at handling the exposure issue you mentioned above. You can see the results of the tests here, we have been discussing this at length for awhile now (Page 26) I also included the max file: Tonemapping - Plz Halp (corona-renderer.com)

Edited November 26, 2020 by James Vella