Half an hour before the deadline. It's been hard work, but the colours in your latest production are spot on. After a quick coffee break while it's rendering, you return to your screen. One last random check before the upload goes live and then, what? Those skin tones suddenly look completely off! How is this possible? Do you really have to ask the client for an extension and start all over again? You wouldn't expect it, but the paint on your walls is going to help you.

 

Working with colour

It can be such a rewarding profession, but working with colour can also drive you mad at times. How is it possible that every time you review your project, the colours look different? Colorists, video editors, photo editors and designers all face this challenge: how do you perceive colour and contrast consistently and accurately, regardless of the time of day? The answer starts with your color grading room setup.

Let's first try to understand what's happening. How do your eyes, or rather your brain, trick you?

 

 

The inner squares are the same colour. Honestly! Try colour picking them.

 

Our optical system is remarkably adaptive. Your brain compensates colour towards a white balance. If there is a lot of blue in your field of vision, your brain balances this by adding the opposite colour. As a result, the square on the blue background appears greyer than it actually is. Imagine that the dot represents your calibrated monitor. That's why those skin tones look so unhealthy. A neutral ambient colour really does matter.

The law of simultaneous colour contrast

The tone of two colour fields appears more different when viewed side by side than when viewed separately against a common neutral background. The chemist Michel-Eugène Chevreul discovered this as far back as 1839 and called it the law of simultaneous colour contrast. If the areas differ in lightness, juxtaposition increases the perceived difference in lightness; if the areas differ in hue, the difference in hue is amplified. Both effects can occur simultaneously.

You experience these illusions when looking at a specific colour or colour sequence on a monitor in a room with mixed light, excessive contrast, coloured walls and other visual distractions that hinder and distort your perception of the screen.

 

 

6 Steps to a color grading room setup you can trust

The solution for reproducing accurate and repeatable colour and contrast is a correctly configured, calibrated viewing environment. In 6 steps, we explain how to achieve this.

We can help you with the right ambient colour on your walls, as described in the final step. But let's start with the most important:

 

1. The right reference monitor

Invest in a good monitor. Regular monitors are not designed for accurate colour work. Consumer monitors are made to make things look nice, even when the source material is not. As a result, the average screen applies all sorts of corrections. And even when you turn these off, they are not consistent in their output. One monitor runs warmer than another, has more contrast, too much saturation, or far too much backlight.

But which reference monitor should you get? There are a number of choices to consider. We use a Flanders Scientific DM170, a 17-inch, 1920 x 1080 10-bit LCD display.

The range of colour-accurate monitors is evolving rapidly, so we recommend scouring the internet for the latest products and reviews. This blog by Jonny Elwyn is highly recommended: he periodically digs deep into the best deals for colour-accurate monitors across different price ranges.

2. Monitor calibration

To ensure your monitor accurately displays the colours it is supposed to, it needs to be calibrated regularly. After calibration, you can be confident that a red pixel is truly red, not slightly orange.

In some cases you can have calibration done by the manufacturer, but you can also do it yourself by purchasing a screen calibrator. Well-known tools include the Datacolor Spyder X2 Elite or Ultra and the Calibrite ColorChecker Display. You attach these to your warmed-up display and the software analyses and corrects the colour output.

3. Keep daylight out

Every ray of light affects your colour perception. This is not only because bright light makes your monitor harder to see, but also because most light is inconsistent, and daylight is no exception. Cloud cover and the time of day influence both the intensity and colour temperature of the light.

The solution is simple: install blackout blinds or curtains. However, blocking out daylight is not without its downsides. A lack of natural light can lead to both physical and mental health issues. Make sure you get outside enough to get your dose of daylight and fresh air.

Colour grading in complete darkness is not recommended either. Without a reference for light intensity, you risk delivering material that is too dark. Your eyes also fatigue more quickly in the dark.

Once the suite is darkened, you will need to relight the space. It is important to do this consistently and evenly.

4. The right ambient lighting

When choosing the right bulbs, two values are important: Kelvin and CRI. Kelvin is used to indicate the colour temperature of light. The warm orange glow of candlelight has a temperature of around 1,000 Kelvin, while a bright blue sky is around 10,000 Kelvin.

What is interesting is that without a reference point, it is difficult to determine what neutral light actually looks like. Your brain corrects for deviations in colour temperature, which means you do not easily notice when the Kelvin value changes. You experience this when you take off a pair of yellow-tinted sunglasses. For a few seconds, the world appears very blue before your brain corrects for it again.

When working with colour, you want to eliminate these kinds of distortions. It is therefore important that your light is neutral and consistent. Choose bulbs with a colour temperature of 6,500 Kelvin, the closest approximation to daylight and therefore the most neutral.

The CRI value, or colour rendering index, indicates how accurately a light source renders the colours of an object. Most consumer bulbs have a CRI of 70 to 85 Ra. For a colour suite, you need a light source with a CRI above 90 Ra. We recommend sticking to one brand for all your bulbs, so you can be sure they do not deviate from each other in Kelvin or CRI.

5. Light placement

Once you have chosen your lighting, it is time to position your fixtures. Make sure no direct light falls on your screen or into your eyes, and always aim the lights away from the screen. In addition, bias lighting (a consistent light source behind your monitors) is highly recommended. There are various reasons why bias lighting matters, but the main one is that it increases your perception of contrast. In our colour suite, all lighting is from Medialight. All sources are 6,500 Kelvin with a CRI of 98-99 Ra.

Match the intensity of your ambient lighting to the brightness of your calibrated monitors.

6. The right wall colour for your color grading room setup

One factor that is often overlooked in a color grading room setup is the colour of your walls. When a room has a specific colour, your eyes compensate for it. A red object on a blue background, for example, will take on an orange tint. You also want your carefully placed lighting to be reflected back neutrally, without being contaminated by colour.

So what is the right colour for your paint? A common choice is white or black. Neither, however, is truly neutral. White reflects too much light, and black absorbs too much. The sweet spot is not a simple black-and-white mix, but rather an equal blend of all the colours in the spectrum: neutral mid grey, also known as 18% grey.

It is, in a sense, the only colour without colour. The 18% figure can be confusing. It refers to the fact that the wall reflects 18% of the light that falls on it. But if you draw a gradient from white to black, 18% grey sits exactly halfway between the two. So 18% grey is effectively 50% black. The reason we do not call it 50% reflectance comes down to the logarithmic scale of luminance. You can learn more in this video. Fair warning, it takes a little while to get going.

Why not just go to the hardware store?

You cannot simply have mid grey paint mixed at a hardware store. You will find a grey swatch that comes close, but getting that exact colour onto your walls is a different matter entirely. The mixing methods are not precise enough, the tolerance of the mixing machine is too wide, and no account is taken of variations in the base paint, which is never perfectly white and can differ between production batches, pallets, and even individual tins. Hardware stores do not adjust their formulas for different types of base paint.

The base paint we use for Grey Paint is the whitest and most consistent available, meaning it is largely free from variation. Every batch is also retested for accuracy. The deviation from mid grey is measured in L*a*b*, where L* represents lightness, a* represents red to green, and b* represents yellow to blue.

Grey Paint deviates by less than 1 point on every value, is imperceptible to the human eye, and performs better in colour testing than the most well-known grey cards.

In closing

Do you have questions or comments after reading this blog, or do you think we have got something completely wrong? Please let me know! I see this blog as a constant work in progress and am always curious to hear about other people's experiences.

It is also worth noting that a colour suite will not do the colour correction and grading for you. Ultimately, it is your trained eye, knowledge and skills that create the perfect image.