The Physics of Color.
Did you ever have a patient, customer, friend or other, say something to the effect of “that doesn’t look like it did on my computer” or “this doesn’t look like it did in the catalog” when they buy something from online or get it home? How about when you print family pics that were taken with a smart phone or digital camera? What about when you went to your local home improvement store for some paint for a room in your home? You either had a color in mind, picked through their color samples or even brought in a picture from a magazine that has exactly what you want and asked them to ‘match it’. Finally, you get it home and go through all of the labors of moving furniture, cleaning, prepping the surface, painting, trimming, and putting everything back in place. You step back and…you don’t like it. It doesn’t look like it did before. Well, you are not alone when it comes to this issue and, if I may, let me try to shed some light on this…
Go Towards the Light
In this first article, we will take a look at the ‘birth’ of color (if you will). Now I promise, this isn’t going to be as scary as when Carol Anne was told to go towards the light in Poltergeist, but there are some ‘interesting things’ and ‘strange phenomena’ at work here as it pertains to color and it is all about the light. Light is energy and the phenomenon of color is a product of the interaction of energy and matter. Color is a sensory event and the beginning of every color experience is a psychological response to a stimulus of light. Without light, there is no color. With light, there is an overabundance of ever-changing colors.
This light and/or matter has the ability to vary the way color is perceived, producing varied results. Not only that, but color is also subjective. One person’s idea of what a ‘true blue’ is will differ from another’s idea of what it is. Is the correct color the one that most closely fits a certain formula? Or is it the one that most closely matches what you think it should be? Color and light work hand-in-hand and there are two primary ways that color is experienced; direct light (Additive) and reflected (Subtractive) light. Let’s take a look for a moment at one of the main reasons for these ‘color issues’ and perceptions in this day and age of digital devices.
Additive and Subtractive Colors
All colors, whether they are seen as additive or subtractive light, are unstable and the results are largely due to (but not limited to) changes in the light and surface or medium (or matter) that they are viewed on. I mentioned previously, that color is experienced in two primary ways and it’s actually a pretty simple distinction between these two.
Additive-based colors are anything that is ‘lit by light electronically to create colors’. This means your television, computer monitor, smart phone, tablet, etc. are all creating colors by radiating light into a luminous object like a light-emitting diode (LED) into sub-pixel clusters. These clusters are typically made-up of only 3 colors: red, green and blue. However, these 3 colors can remarkably create a whole sub-set of millions of colors for us to look at. They stimulate our senses and make us believe it is a ‘real-to-life’ representation because that’s what we spend the majority of our time looking at these days.
Electronic viewing devices use a black screen and need to add light to create color. Oddly enough, additive color is really only a product of 20th century technology and hasn’t been around that long. Despite it being relatively new, it has taken over our society, our lives, and is now what many people are basing “what it should look like” on. Don’t believe me? How many people do you know (yourself included) that do the majority of their shopping online and don’t even bother going to stores anymore? We think that because we are looking at a picture, taken with a camera, that it is a ‘real-to-life’ representation. But it’s not. It is so common these days that it has become ‘default’. It is actually a simulation that we perceive as ‘good enough’ when, technically, it is only a fraction of the actual colors available in the real world, which I’ll explain in a moment.
Subtractive-based colors are the colors we see in the physical world around us that are lit naturally and not lit by electronically harnessed light like a computer display. The colors of Bryce Canyon, paint daubs on canvas by Monet, the grass, flowers, carpeting, walls, tapestries, clothing… even this magazine. All these and much more are considered to be Subtractive. Subtractive-based colors are the result of the majority of light waves being absorbed by an object or surface and those that are not absorbed are reflected back, giving us the color we see. In the print world, cyan, magenta, yellow and black are used to create the majority of what we see in print. Paper is white, so printers need to remove light to create color. Canvas and artist’s paper in general is also a form of white so artists have their own set of colors to use and mix (red, yellow and blue). Either way, the end results are produced by light waves being accepted and rejected, thus resulting in the colors we see.
I know that this is only a ‘high-level’ breakdown of the two primary types of color that we see but, with that, we can begin to see that there is already a big difference in the colors used in our daily lives. Additive uses the RGB color space and Subtractive uses CMYK color space. This is a huge reason/culprit why colors we see on the computer never look the same when you hit the print button and is a big reason why people will say “it doesn’t look like…”, as I wrote in the introduction. To better understand these differences, let’s take a closer look at the differences between these color spaces…
Color Spaces and Beyond
Additive Colors, on most computer displays, have 3 primary colors. Red, green and blue. Mixing some of these colors will produce paler secondary colors like cyan, magenta, and yellow. Mixing all of the primaries at once will produce White. Remember, this is color generated by light; not paints and pigments. Modern computer displays and devices will represent each color (RGB) with each color having 256 shades. This combination of RGB gives us over 16.7 million colors and has become widely accepted as what the human eye determines as true or ‘real-to-life’.
Subtractive Colors, like pigments, are more familiar to us when it comes to mixing colors. Red, yellow and blue, are the primary pigment colors here… the same colors you may have learned about in kindergarten. Mixing combinations of two of these pigments will give you secondary colors like orange, purple, and green. Theoretically, mixing all of these primaries will give you black… although that’s actually not possible.
As it pertains to print these days and CMY (cyan, magenta, yellow), each color has a value from 0% to 100% and can produce 1 million color variants. The addition of black (K) helps remove more light from the white of the paper and provides shades for more color variations. The cyan, yellow, and magenta inks for printing yield better results for allowing light to penetrate and mix with the white of the paper than the traditional artist colors of red, yellow and blue.
RGB has a larger color space or gamut (below) of color than the CMYK gamut does. When you are viewing an image on-screen and want to print that image, the printer does not offer enough color with CMYK to allow for all the colors to show. Colors are converted and/or ‘dropped’ when you print from a computer, which is why your print never looks the same as it did on screen. It looks a little darker, a little less saturated, and a little duller. The white or ‘brightness’ of the paper also mutes the colors because it’s not as bright as the light on the monitor. This is one of the major areas for discrepancies with the perception of color and having an unhappy customer. You can extend the color range of CMYK by using pre-made inks known as spot colors, which will certainly raise the overall quality of the print, but it will also significantly raise the cost. It also won’t actually solve the issue, as it still doesn’t get close to the visible spectrum.
The Visible Spectrum (below) is what humans can see. Despite the differences in color spaces between RGB and CMYK, with RGB having more colors available, they fall well-short and are only a fraction in comparison, to the Visible Spectrum. The Visible Spectrum contains numerous colors that are distinguished by wavelength, which determines color, and by amplitude, which determines brightness. The combination of these light waves produces white light, which is what we see from the Sun and from most artificial light sources. What we can see with the human eye is known as Visible Light. Speaking of light sources…
The Physics of Light
Physicists explain color as a function of light. Color is a visual experience and is only available and seen by light. Not all light, however, is created equal. As a result, this creates a lot of instability in the way color changes. Light is visible energy that is emitted by a light source and it does so in the form of pulses or waves. Light may travel at the same speed, but the waves are emitted at different frequencies. The distance between the peaks of these frequencies is known as wavelengths, which are measured in nanometers (nm) (bottom left). The human eye is only sensitive to wavelengths that range roughly between 780 nm and 380 nm. Infrared lies just below red light and ultraviolet exists just above violet light. Both of these are invisible to humans and most other critters (although some reptiles see infrared; some insects see ultraviolet).
When you shine white light through a prism (or look at a certain Pink Floyd album cover), the prism refracts the light into separate colors (wavelengths) that make up the white light. Each of these wavelengths bends at a slightly different angle and emerge as a single color: red, orange, yellow, green, blue, indigo or violet (ROY G BIV). The strength of the white light has a lot to do with the strength of these colors as does the quality of light. The surface, thickness, composition, opacity, translucency, refraction values and other factors of the object/matter will affect the light passing through and also have an effect on the colors produced.
A manufactured light (better referred to as a lamp), such as a light bulb, are all designed to emit white light with RGB. The problem is there is no ‘standard’ for this white light, nor will it ever be pure white. Each one of these lamps provides light of a slightly different color, temperature, and quantity of light, even emitting all 3 primary colors. Various lamps emit more or less of certain colors of RGB and are measured in the Kelvin Light-Temperature Scale (below).
All of these variations in the manufacturing of the different lamps will yield different visual results of the colors we see. A typical incandescent lamp in your home has a low temperature around 2600-3000K and provides a warm-white, yellowish light. Lamps that have a higher temperature like LED’s in your computer screen, have a medium temperature in the 6500-7500K range and provide a cool-white, bluish light. The variation of color emitted will greatly alter the resulting color being viewed. Think about those new fancy ‘energy saving’ bulbs and how it drastically altered the look of everything in your home or office when you changed them out.
You can also see these differences in quality of light by going to a local electronics retailer and looking at their ‘wall of televisions’. If you look at them from a distance (they are usually running the same, synchronized promo on all of them which helps in this case) you can see the variation of light, colors, and quality of the different devices. Your more expensive or high-end devices like Apple products, generally have a higher luminance value around 375 cd/m2 whereas ‘average’ displays hover around 250 cd/m2 (candela per meter squared (cd / m 2)). A candela is the standard unit of luminance and represents a luminous intensity from a surface that is 1 square meter. This difference in luminance drastically alters the quality of the vibrancy and saturation of the colors we see. When you are staring at 1 device at a time, you have nothing to compare the quality of light and color to and you end up accepting what you see as being correct which becomes ‘your benchmark’ for what something should look like. Is your head spinnin’ yet?
Oh what fresh hell is this?
Just as Morris the Cat was very finicky, so too is color under various lighting sources (above) but there are even more variables to factor and consider. Just like we have a varying array of luminance values for Additive-based colors, we have varying values of brightness for paper and Subtractive-based colors.
The brighter the paper, the more vivid and vibrant the print can be. The surface of the paper also plays a key role here. Average copy paper is very rough (and dull) and will make colors look darker. Not only is the paper thin with a level of translucence, but the roughness of the surface allows light waves to bounce around more and create muddier colors. Higher quality paper with a smooth finish will allow the colors to be more accurate and true.
It’s the same when you try and paint your walls at home. If you do not prime the wall and just paint over top of a pre-existing color, you will not get accurate results with the color you chose. A primer provides a smoother and whiter surface for your paint to be applied to and allows the color to be more true and accurate. Otherwise, you may have to do 2 or 3 coats of paint over the top because the light waves are not hitting an ideal surface to show the color accurately. Paint and pigments, much like CMY (depending on the color), have varying degrees of opacities which will allow more or less light to penetrate the surface. This can wreak havoc on your ‘desired color’.
Speaking of the colors of the walls, a wall color can alter the color of adjacent walls. So too will the types of lights that are used in that area; as will the color of the carpet, flooring, ceiling, furnishings, mirrors… basically everything will have an effect on the wall color. Go ahead and make that inquisitive sound that Scooby Doo does if you haven’t already.
What is happening here is something referred to as Global Illumination (below). Global Illumination is the bouncing of indirect light. When light hits a surface, ‘x’-amount of colors are absorbed and ‘y’-amount are reflected. Not only does this give us the color we see, but if the area emitting these bounced waves is big enough, light transfers from one surface to another, carrying color and providing a ‘color-cast’ on adjacent surfaces. This bounced light is how we can see under our desks. There’s no direct light source under your desk so how is it lit? Bounced light.
Think about going to the movies. Outside of the safety lights (and the few people who can’t put away their smart phones for 2 hours), what is the lighting in the theater? How can you see people’s faces? The light source is the projector behind you… but when it hits the screen, the screen becomes a secondary light source and bounces light. This bounced light has colors in it… the same colors you see on the screen and will light-up people’s faces with a paler, less saturated version of those colors.
The Science of Colors
The last aspect that I wanted to touch on regarding color and light is what can happen when you start applying light filtering colors over top of something that is already tinted. Remember that Subtractive-based color is created by natural light and further manipulated by the quality of that light and the surface that the colors are on. Color is the result of light waves that are reflected and were not absorbed. Take for instance a polarized lens …
Some lenses or pucks have tints to them based on their manufactured composition. Polarized lenses may have a gray, brown or a gray-green tint (either warm, cool or neutral) to them already. That is their nature. These colors will, by default, alter the appearance of what a person wearing them sees. It will make the world they look at slightly tinted with a ‘kick’ of color based on the tint of the lens. What if that customer wanted a mirror-color coating on top? This will further ‘alter’ the colors of what they are seeing because certain light waves of color will still pass through and mix with the tint of the lens. For example… let’s say that you have a customer in your store that chooses a polarized lens in gray. For starters, they are inside, under less-than ideal lighting conditions for viewing glasses that will also be worn outside. This ‘gray’ will slightly tint what they see through the lens to begin with. If they wanted a blue mirror coating applied on top of a warm-gray polarized lens, there will be a mixing of the warm gray and blue that might actually create a brownish/reddish hue to what is being looked at through the lens. The reason is that although a blue coating was applied, to create ‘this’ color blue, it only reflects back a small range of the blue that makes up the final color. The rest of the blue in the spectrum passes through and can mix with the gray of the lens. (below)
This, of course, can make a customer very unhappy. Because of the gray of the base lens, which may contain some red and orange in it (warm gray) mixes with the light and the blues ‘not’ found in the blue coating, producing a completely different color than they were expecting, and chances are, a color result they don’t like
Rock - Paper - Scissors - Lizard - Spock
Bazinga! You just fallen victim to a practical joke of physics and light and colors. Technically, it’s not a joke and is actually a result of the physical properties of color and light. To paraphrase Dr. Cooper, ‘your problem is not with me, but with basic physics’. Light, color, and filtering is messing with you and your customers and here’s why (the point of all of this). Most colors do not reflect a single wavelength, so there is always going to be a mix of subtle colors. As it pertains to colors and the wavelengths they reflect, some colors have ‘shared wavelengths’ and some don’t. A warm yellow (has some orange) and a warm red (has some orange) will share a similar wavelength that produce a nice orange when mixed. A cool yellow (has some green) with a cool red (has some violet) does not share the same wavelengths and will produce a muddy brown (green + violet). This makes it difficult to know the results you may get when coating a tinted lens but now you know why colors can ‘go wrong’.
So how can any of this help you? For starters, I’m hoping this article provided you with a few new and different perspectives as it pertains to looking at color. I’m not at all recommending that you immediately change all the colors and lighting in your dispensary upon reading this, but you should look at your showroom environment a little differently now and how it may be affecting the results of what you and your customers see.
Having an understanding of color, light, and causes for the varying appearances of color, should help you better-educate your customers when it comes to their color choices. You can hopefully provide them with some explanation before they make their purchase of what can be expected. Having tangible samples of things like tinted lenses with colored mirror coatings will prove to be invaluable when it comes to helping your customers and to see more accurately what they will be getting.
– W. Carter Merbreier