Color Management: Wide Gamut Displays in a CG Workflow

Despite the title this article applies just as well for non wide gamut displays.

Even though I am writing this article from a CG Artist’s perspective, most of the information is relevant to photo and film workflows as well.

“Everything you always wanted to know about color management
but were afraid to ask”

I’ve recently done some extensive research about color management, ICC profiling, “mysterious” color changes when leaving Photoshop and how it applies to a 3D workflow (as well as photo or film workflows). There’s a ton of information and advice out there when googling the subject. Much is contradictory and more or less causes confusion instead of enlightenment when trying to understand what is going on.

After a few days of extensive research, filtering all kinds of information from articles, books and forum threads as well as my own tests and explorations I have got a pretty good understanding of how it all ties together.

Armed to my teeth with this knowledge, I thought I’d share my findings and workflows by writing an article on the subject.

In this article I’ll talk about how to calibrate and profile your display and then how to configure and setup your 2D, 3D and post processing applications for a color managed workflow.

Background

Well, I actually believed I had somewhat basic understanding of how color management worked, but about a month ago I realized that I did indeed have a problem. It started with my Dell 2407 WFP display dying on me after a few years of heavy usage and Dell sent me a new replacement screen. I got a newer model, the Dell 2408 WFP with a wide gamut display.

Hardware and Software

This is the hardware I am currently using and the software I’ll be referencing in the article.

• Hardware: Dell 2408 WFP wide gamut display, Datacolor Spyder 3 Elite display calibration.
• Software: Photoshop CS4, After Effects CS4, LightWave 3D, modo, Firefox, XnView.
• OS: Windows Vista (The wide gamut “problem” exists on Mac OS as well, and much of what I write will apply there).

LightWave 3D is as far as I know the only 3D application on the market that allows true color management (through a free plugin). I was a bit surprised that modo 401 didn’t provide full color management in it’s new release as wide gamut screens are getting quite common – especially in the market modo is targeting at the moment, where seeing correct colors while rendering is important.
Full color management is also in the works for Blender, I don’t know if we’ll see it in the coming version 2.5, but if we do, I’ll definitely take a look at it.

I believe it’s pretty hard to find a large screen today which isn’t a wide gamut display, and I guess that it will soon be more or less impossible, so I really hope more CG applications will be fully color managed in the future.

The Problem

After having received my Dell 2408WFP display I started seeing some really strange color shifts going on. When I had worked on an image in Photoshop and saved it out and opened it in another application all colors appeared extremely oversaturated. And when I say extremely I really mean it. Reds where out of this world. The same was true when just browsing the images on my own site in Firefox. Characters that I was earlier pleased with looked like they where suffering from a bad hangover with oversaturated skin tones and so on.

The same was also true the other way around, when I had worked with a 3D render and was happy with it, saved it out and opened it in Photoshop for post processing nothing looked like the render I had saved out. Colors became very dull and dark.

I started scratching my head to understand what was going on, I had seen small shifts in colors many times before when going in and out of Photoshop, but nothing even close to this. I tried recalibrating my screen several times with my Spyder 3 Elite but to no avail, and reached a point where I was almost afraid to deliver new images because I was so confused and didn’t know anymore what was right or wrong.

Were the colors correct in my render display when working in LightWave 3D or modo for instance and Photoshop was the bad dude that screwed them up? My screen was correctly calibrated to my understanding at the time. Or was Photoshop correct and everything else wrong? How did other people see my images? Did they see them like how I saw them in Photoshop or like they looked in my 3D application?

Lot’s of questions and no real answers to be found in an easy way. Little did I know that the wide gamut (words I hadn’t really paid attention to) was the cause of me seeing the problems so clearly for the first time when jumping between color aware and non color aware applications.

Anyway, I faced a situation that made it impossible for me to work as usual, so I started digging, I needed to know and foremost understand what was going on. As long as one understand what’s going on and why it happens, it’s not really a problem anymore.

So there did my quest to battle the oversaturated versus dull colors start.

Concepts and Misconceptions

Okay, let’s start with clearing up a few concepts so we get a better understanding of what’s really happening. I want this to be a very clear article that do answer the questions many people with these kind of problems are facing instead of generating more confusion. So let’s give it a shot.

• Wide Gamut
  Starting with the oversaturated colors on wide gamut displays. In the past displays were showing colors that were pretty close and limited to what we know as the sRGB color space, with newer displays we have a much larger color range to work with – closer to the Adobe RGB color space. When an application wants to display a pure red pixel (RGB 255,0,0) it sends a signal to the screen that the brightest red should be displayed.
  A non color aware application (we’ll go deeper into this further in the article) just dumbly assumes that the display is within the sRGB range and blindly sends the raw pixel data where in the case of a wide gamut screen, which can display much brighter colors, receives the signal of displaying the brightest red, do just that, displays the brightest red that it’s capable of, which then leads to the extremely oversaturated image.
• Calibration
  When calibrating a LCD display with a hardware device like the Spyder 3 from Datacolor, most people understandably assumes that the display will be calibrated to correctly display colors in the sRGB space.
  That is an incorrect assumption.
  A more correct label is that the display device get profiled, that means that the display’s color performance and characteristics get measured and saved in an ICC profile that color aware applications will use to display colors correctly within selected color spaces. Some calibration do also occur but non in the same sense as in the CRT era where displays where within the sRGB range. LCD displays doesn’t get truly calibrated at all towards a specific color space, they get their Gamma and White Point values calibrated. This is an important concept to understand and as soon as I got it, it all started to make sense to me.
  Profiling is the keyword here.
• Non Color Managed Applications
  Even though the display now has been calibrated and profiled, non color managed applications will still display colors incorrectly, this is especially true on wide gamut displays. And there is simply nothing that can be done about that except using color managed applications. Wide gamut displays are great and the future, but software developers need to catch up with the new hardware and stop assuming all displays are within the sRGB range. I guess this will happen in the coming years and more and more applications will start using and respect color profiles.
• Color Matching
  Every display is unique, so one can never achieve that colors will look the same for everybody. But having a color managed workflow and a system properly configured will allow you to create images that will look the best on other profiled systems and for the “big masses” with ordinary displays you will have an image that is the best compromise.
• Trust Photoshop
  When the display has been calibrated and profiled color managed applications like Photoshop will use that profile and modify its display correctly according to the selected color space. So the colors that you are seeing within Photoshop are the “correct” ones that most people will see something close to.
• The Monitor RGB Trick
  Never ever use the “trick” Proof Setup » Monitor RGB in Photoshop to get the same colors inside and outside of Photoshop. That will only ensure that you are truly messing up colors that probably will look wrong on most other people’s displays, especially those with newer ones. That’s a real bad advice that has been circulating on blogs and forums and should not be adopted. Then you are totally missing out on the power full color management provides.
• Gamma Correction is not full Color Management
  Some 3D applications has recently claimed to have complete color management, like Autodesk Softimage. While the application have received some very impressive tools for a complete gamma corrected linear workflow, it’s still not fully color managed. Gamma correction is part of the color management, but only deals with luminance. A complete color management system must also handle color spaces and soft proofing.
  Most 3D applications have gamma correction of some sort, but the only ones with true color management in color spaces with soft proofing is LightWave 3D with the SG_CCFilter plugin and maybe the coming Blender 2.5.

To sum this section up; the new wide gamut monitors can render much more saturated colors (which is good, when working with color spaces such as Adobe RGB). Images that are displayed without color management on such a monitor will appear very oversaturated.

The only way to get correct colors everywhere is to have color management throughout the system. Every application dealing with images must respect the image’s ICC profile as well as your display’s ICC profile. And every image must be tagged with the proper ICC profile.

Many images today isn’t tagged with an ICC profile, especially on the web, and an untagged image is always shown incorrectly even in a color managed application unless it’s displayed on a monitor within the same color space as the image was designed for. It works out like this:

• Untagged sRGB image » Regular sRGB gamut monitor » Correct colors
• Untagged sRGB image » Wide gamut monitor » Oversaturated colors
• Untagged Adobe RGB image » Regular sRGB gamut monitor » Undersaturated colors
• Untagged Adobe RGB image » Wide gamut monitor » Close to correct colors

With more and more monitors on the market with different gamuts it has become very important to always correctly tag images with the appropriate ICC profile, and to use color managed applications to ensure the best possible color matching. Which is the only existing cure to get consistent colors on different displays.

Color Managed Applications and Workflow

Now when we are armed with the understanding of color management and the importance of profiling the display and correctly tagging images with ICC profiles, you also need software that are color aware to make use of all these goodies.

I’ll walk through calibrating and profiling your monitor and some of the applications I use, there are many other color aware applications out there, but I will keep it at my personal workflow.

I am currently using Windows Vista as my OS, and Vista isn’t color managed in itself, which means that the desktop image, icons, previews etc are displayed oversaturated on my wide gamut monitor, and there is no way around that. I don’t know if Windows 7 will be more color aware, but I guess that could be pretty tough to tag everything displayed in an OS with profiles, perhaps in the successor to Windows 7.

Which leads us to the next section…

Article Overview

1. » Introduction
2. Display Calibration and Profiling
3. Photoshop Color Management Setup
4. Color Manage 3D Renders in Photoshop
5. The Linear Workflow
6. Render Display Soft Proofing
7. Compositing and Editing
8. More Applications and Conclusion