Demystifying Color Management
When we start talking about translating information from capture, we're talking about our camera, what our camera sees and how our camera should be set up. Most important, never discount this part here. We're trying to put ones and zeros and pixels on a sensor, okay? Digital data. But the right digital data that translates to the final print. What we capture then has to be translated electronically to a monitor, and then the monitor has to translate that information again to a print. There's a lot going on there. And there's this thing here that governs all of those three things: color management. The scariest word in every photographer's vocabulary, color management. I strongly believe that, as a photographer serious about your work, before you learn lighting, before you learn anything about photography, you need to understand this because this is gonna alleviate 99 point 9 percent of your frustrations with what you're doing with your images. It's great buying a new camera, it's great...
taking pictures, but then, what are you gonna do with them? If you understand color management and how to implement color management workflows within your environment, life is gonna be a lot easier. So we need to understand the properties and the human perception of color, which is an integral component in fine art printing. So we need to understand how we manage this color, basically. So, what is color management, really? So when we look at the classic definition of what color management is, color management is the implementation of procedures for the achievement of color consistency irrespective of device within a digital imaging system. What does that mean? Basically means that what I see on my screen is what I wanna get back in the print. Very simple. What is a digital imaging system? Well this is it. We spoke about it, and we're gonna be referring to this diagram a lot over the duration of this course. The translation of information from camera to computer to printer and backwards and forwards, so that the camera translates information here, your computer translates that information, your printer understands what the computer is trying to say, and everything is beautifully contained and everything works, and the angels are singing, and it's a wonderful world, 'cause that's what I like to see. Does it always happen like this? Not quite. (chuckles) There are gonna be hurdles along the way that we'll address. But this is what a digital imaging system is. So before we get too far into this, we have to define a very, very important term. We talked about color management, but really, what is color? What is color? How do we define color? One of my favorite characters from growing up as a kid was Kermit the Frog, and he used to say "It's not easy being green." Well, he's right, because he wasn't color managed back in those days. That shade of green was different on different TV screens. And we don't really know what shade of green Kermit was. Kermit was Kermit, but he was a shade of green, but what is color? To us humans, it's easy to describe color to a fellow human. You know, it's red, and it was orange, and it was warm like a sunset. Great. Explain what a sunset is to a monitor or a printer. You can't, because they don't understand the English language. So, color has to be translated mathematically for these devices to understand really what's going on. What we can say, though, is that color is a property of an object. Would you agree? Color is a property of an object. If we can't describe color in the terms of what we feel about color, warm like a sunset or it's green like the grass, 'cause we're using real-life scenarios, but we can say that color is a property of something. Color is a property of light, as well. And color, this is the thing that a lot of photographers stumble on, color is characterized, in other words, defined, by the human visual perception. So what does that mean? It means that I could hold up a red piece of paper here and every single one of us in this room will know it's red, but we'll all see that red slightly different. Our perception of what color is is a little bit different in each and every one of us. So in other words, you can't really trust your eyes when you start to look at color management. You can to a certain point, but then the mathematics have to kick in, where we translate color by numbers to make things really, really work. So when we look at color in the real-life world, it's basically a three sub object event. We have light source that shines onto a subject. That subject takes on the light source and, with it's own properties, reflects back a light source to our eyes. So light is changing here, so we have a light source, takes on, it's like we have a light and we shine it onto a red wall, we have white light, we shine it on a red wall, the reflected light is no longer, why? It's gonna be red. It takes on the properties of whatever you shine it on. And then, the unknown factor number three is these. I'm seeing a kind of a shade of red, but you're seeing a different red. And if you're color blind, you're seeing green, maybe, I don't know. Or blue, or you're seeing something totally, totally different. So this is how color works in our world, and when we look at the spectrum of light, the visible spectrum, these are very, very small spectrum, and this is what we deal with in photography, beginning with visible light at the violet stage and ending with red wavelengths when you mix all these together. In a minute, I'll show you how we get to white light, but we have the visible spectrums and just outside this spectrum here, we have two things that we deal with also with digital photography. On that end, we have ultraviolet, which is dealt by your sensor in your camera and your filters in front of your sensor. Sorry, the infrared, that is. And then the ultraviolet side comes in, obviously, when we start to view prints and how prints start to look differently under different lighting conditions, which we'll talk about that a little bit later on. So, longer wavelengths, shorter wavelengths, and the way we represent color and the order of color always, we'll go with the longer wavelength first and the shorter wavelength last. So, this why we call it RGB. This is why the order has always been RGB, no GBR or BGR, so RGB, but the full spectrum is red, orange, yellow, green, blue, and violet, and that's the order that the colors will always appear in. Even when you see a rainbow, that's the color. So with light, when you start to mix RGB together, we can end up with everything single possible color under the sun if we start to mix these in different amounts. But if we mix them all in equal amounts, we get white light. And this is the basis of how color management works or how color works in our cameras, but also, this is how color works in our eyes. It's basically an RGB kind of thing that happens, okay? So, at the end of the day, we can't really trust our eyes when we start to look at color, okay? We need to be a little bit more astute as to how we can get color perfect each and every time. Our eyes suffer from one very important thing, and it's color constancy, not color consistency. Color constancy, what does that mean? It basically means that our eyes discount the color properties of the illuminant. So, if this room was tungsten-lit, and I'd be wearing, say, a red sweater, everyone will say, you're wearing a red sweater, even though it's being lit by tungsten light and it's gonna look a lot orange-ier than normal, but our eyes have an auto white balance system built into them, and I'll take that red sweater outside and it's still a red sweater, because our eyes have adjusted. So they work kind of like the auto white balance works in your camera, but it's much, much more sophisticated. Cameras don't quite do that. A camera, if you set it just on daylight because that's what you're thinking your capturing, you have different color temperatures coming in, you're gonna get different colors. So our eyes will constantly adjust. The same if I was photographing a bride, and I'm photographing a bride in a garden underneath a tree with beautiful green grass, and I've got sunlight filtering through and it's taking on the properties, remember what we said about the properties of light and how you got the properties of light taking on the properties of the object itself that it's lighting, so through the tree, so, essentially, what we're getting, lighting the subject is not really nice, clean, white light, but what is it? It's kind of a greeny kind of shade, but you'd never see that with your eyes. You'd go, yeah it's white. It's beautiful light, we're gonna work with this, and everything's fantastic, only to find out later on that maybe when you open up your files and you look at them on a beautiful, color-graded monitor, you're starting to that sighing green creeping through your shadows, because that's really the color of the light, and that's what the color was doing. Also, what happens with our eyes is they suffer from memory colors. What does that mean? In other words, there's colors that we just know and we're familiar with, and we know what they're meant to look like. One of those colors is human skin. We know roughly what human skin has to look like, and if someone's off-color or not feeling well, we can see that straight away, can't we? Because it's embedded in our DNA. There's a certain memory to that color. And then going down, of course, something like green grass. We know grass is green, and the minute we open up an image on our monitor or we do a print and that grass is purple or a shade off, purple with some green in it, we know something is wrong. Blue skies. Blue skies are a blue sky. We know that the sky is meant to be blue and if the sky is not quite like that, once again, if we go down to the purpley hues, or, of course, skies are blue, but they can be different colors depending on the time of day, but generally, a blue sky in the middle of day is meant to be a blue sky, and not a green sky, not a purple sky, it is a blue sky. And these are things that we just constantly discount because we know what they're meant to look like. So, in other words, we can't trust our eyes, and monitors and computer don't speak our language and cameras don't speak English, so the measurement of color and the need for color profiles is essential in our photography world. So it's all about colors by numbers. When we produce color on a physical device like a monitor or a printed page, we do so by manipulating red, green, and blue light. Cameras and monitors work with RGB. That's what we do. So, there needs to be color recipes that create certain colors that the monitor understands and then the monitor can then interpret to be printed on a page. So we need color profiles. So what is a color profile? Well, a profile translates color in a language that the particular device understands. Monitor profiles translate what you input into them like what the camera basically captured in your files. So the file is saying, this is the color, the monitor says, I can display color a certain way. The profile comes in the middle as a translator, speaking both languages and says, Mister Monitor, the camera says it was this particular shade of green. He goes, yes, of course, I can display that. That's basically how it works. That's the role of the profile. In printing, it's the same. The monitor has a color and the translator says, this is the color that we want to take to the printer. The printer says, I know how to deal with that color, Mister Translator, because these are the numbers. And that's what the profile does. In a very, very simple term, we need those profiles. And the way those profiles are created: a device's color response is characterized by the numbers that are sent to a device, in other words, the color numbers, and its output is measured in each instance and the profile is created. So we might send a particular shade of green to a device. We know what that measurement is meant to be for that shade of green. We measure it out of the device, there'd be a color difference, and that color difference is measured, usually by software, and the profile is created. That's in a very, very simple term. That's basically how profiles are created, not only for your monitor, which we'll talk about a little bit later, but also with your printing profiles. Input, we know a value for an input, and then we measure the value of the output, there's a difference. What is that difference? How is the printer, or the paper combination handle that particular shade? That's the role of the profile on how we get that information across. So, when we look again at this diagram, ICC monitor profiles interprets color numbers from the camera and displays them according to the calibration parameters of what we set in our monitors. Monitor calibration is a huge thing, and probably, not probably, it is the most important component when we start talking about color management and fine art printing. And then of course, your printer. Print/Paper profiles translate color numbers from your monitor to the color values on a printed page in very, very simple terms. So understanding color, but understanding color by numbers as opposed to just descriptive words.