Digilabs Technologies Blog

Matchmaker matchmaker make me a match…

Posted on: April 30, 2010

If you’re not sure were the title of this blog posts comes from, take a look at this video.   Fascinating as it is,  this post will not deal with matchmaking but with color matching.  No, not matching you shirt with your jacket…the “other color” matching.

Basically, how do we match the color we see in one place with the color in/on another.  For example, you want your company logo red the same color, no matter where it is printed.  Otherwise, why did you pay gazillions to those corporate identity guys.  You want it to be the same red on your web site, your power point presentations, your brochures, your magazine ads, and even on the billboard near the highway…so you see it every time you drive back from the office at 8.00 PM. The problem is, how can you make all those reds match.  Heck, your logo may have other colors in it.  You want all of them to match. That is “the other” color matching, and it is not as simple as it sounds.

This post will just layout the ground and show why this problem is a real hairy one. The next post will discuss what can be done about it.

The first thing we need to discuss is color. What is color and what is color made of?

We have a light source, let’s say the sun. This light source omits numerous waves of energy, each having different wavelengths. All of them combined together look like a white light (although some of the frequencies are not in the visible range, such as Ultra Violet (UV) or Infra Red (IR)).  This light hits the surface on an object, for example a red apple.  The surface absorbs some of the frequencies and reflects the rest. In our case it reflects the waves that are in the red range. Those waves get to our eyes and hit some sensors that can interpret those frequencies as red, green, or blue. This information pass through our optic nerve into our brain and creates the perception of color. This is called a Subtractive Color model – as the frequencies that are not absorbed form the color we see. We also have the Additive Color model, where we project different frequencies, adding them together to create the color. Printed color is subtractive, while projected color (TV, monitor) is sdditive.

So if color is light, what is color where there is no light? Is the apple red but we just can’t see it or is the apple something else? This may be a philosophical question, but also a very practical one.  My logo’s red is going to look different under different light conditions. Since red is an attribute of the light it reflects, the same red will look different on noon in an Arizona’s summer than noon in a Seattle winter.  It will actually look different based on the type of light, be it the hour of the day, weather, lighting conditions or even our latitude and longitude…you name it.  So what we have here is a real problem of definition. We need to agree on the environment we are going verify that the colors match.

The second variable is the reflective surface. Some frequencies will be absorbed buy the surface while others will be reflected – this gives our brain the perception of color. We do that by spreading ink on the surface. However the surface participates in the process. Printing on a white paper will give different results than printing on black paper. And as anyone who painted their house with some white variation knows, not all whites are created equal.

So now we get to the question of how we can define color in a way we can communicate it. There are few ways to define color. For example, since we said our eyes recognize red, green and blue, we can try and define each color as a combination of red, green and blue. This is what us known as RGB color. We define the color by three values, 0-255. So black is 0, 0, 0 (absence of color) while white is 255, 255, 255 (full color). The CMYK (Cyan, magenta, Yellow, Key black) is used in the printing industry defines color using four values, one for each. There are the CIE color space, HSV and HSL (hue, saturation, value and hue, saturation, lightness). If you want to learn more, look here

This way of defining color adds limitations. Wave length or frequencies are analog, and they are continues and infinite. In other words, you have infinite combinations that can represent color. But the way we try to represent color is digital.  Lets take RGB – if each color channel can have 255 values, the total number of colors we can represent in the RGB model is 16,581,375. This sounds like a lot, but it is still less than infinity and we need to decide what colors will we use these values. Also, not all color models are compatible. We can define some colors in one color space that we can not define in another. See the following image to see the different color space range.

Lastly, we have to consider that eventually we will use a mechanical device to print or project a color. Those devices do have limitations. They can not produce the full color gamut.  So, not only can we not define all colors, but we can not produce all the colors we can define. Even worse, this is difference in devices causes different colors to be produced differently.  Below, see an example of a TV viewable gamut.

To sum it up, color is a variable of light and light conditions which vary.   Its production depends on the material used to produce it and on what we produce it on. We can not define all colors. We can not print all colors, and each machine can print a different set of colors.

With such a mess it is a miracle we can print color at all.  Next time we will discuss: How can we make your red logo colors match?

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1 Response to "Matchmaker matchmaker make me a match…"

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