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Introduction to Colors

Whether it's the blue sky up above or the green grass growing in a field, an infinitude of colors surround us. What makes a color and how can there possibly be such immense variation? After all, color is an intangible thing and seems to be an innate property of nature apparent in everything that exists. To begin to understand how the properties of colors arise, let us take a look at the basic principles involved.

Ingredients for Perceiving Color

There are three main ingredients needed to perceive color:

Light
Vision
Object

If one of these ingredients is missing, color does not exist. For example, say we take a person, Sarah, and put her in a room where there's a red apple sitting under a white light. There is light, an object, and a viewer, hence Sarah would see the apple as red. If we were to turn off the light, the apple would not be visible and Sarah would not perceive its color as being red. Take away the viewer or the apple, and of course there would be no perception of color either. But what makes the apple appear red instead of green or blue? For that we will have to delve into a little bit of physics.

Physics of Colors

Waves

Light is a part of the electromagnetic spectrum in which many useful forms of energy exist.

Energy in the electromagnetic spectrum occur in the shape of waves; from the very long and low energy FM radio and Television waves which can be up to 10 feet from peak to peak to the diminutive and unimaginably small and powerful Gamma rays whose peaks may be spaced smaller than the electron of an atom.

Visible Light Spectrum

Somewhere in this mix of different sized waves is a very small and specific section of wavelengths which the human eye was designed to see. This is called the Visible Light Spectrum.

Within this visible light spectrum is every color imaginable, starting with Red at the longest wavelength (780nm) and going to Violet at the shortest wavelength (380nm). Any color that has ever been seen or created is (with the exception of monochromatic light) a mixture of light at various wavelengths within this visible light region.

Reflection and Absorption

A pure, white light contains every wavelength of light within the visible light spectrum. That is to say that it is made up of every color within the spectrum. The reason that an object can appear to be a certain color, for instance the red apple used in the example earlier, is due to the fact that when white light is shined upon it, the apple reflects wavelengths of light which appear to the eye as red (~680nm-780nm). If we instead used a green apple, it would appear as such due to its reflection of the green wavelengths of light within the visible spectrum (~500nm-550nm).

An object that is black, on the other hand, absorbs all light that is shined upon it and doesn't reflect anything back! That's why wearing black on a hot sunny day is a bad idea; the black clothing absorbs light as heat which warms you up.

Defining a Color

Defining a color can be a very subjective and unscientific task if proper measures are not used. For instance, take a look at the two orange balls on the right. They are very similar at first glace as they are both orange, but upon further inspection it becomes apparent that there are differences. The one on the left is darker than the one on the right. Also, the left ball is a duller orange color while the right ball is more vivid.

That leaves us with three defining and measureable characteristics of color:

Hue: The color. Orange, red, blue, purple, green - these are all hues.
Lightness: How bright or dark a color is.
Saturation: How vivd or dull a color is

It is these three values that we use to define one color over another in a quantifiable manner. This becomes especially important when creating a brand or product as the ability to define and control colors is central to their reproducibility and brand recognition.

Color Spaces

Color spaces are mathematical models with either 3 or 4 sets of numbers, that can be used to determine an exact color. Imagine that we take a sphere and by using a very specific method, fill it with every color imaginable. By assigning numerical values to an X, Y, and Z axis, we can locate in that sphere the exact color we are looking for. This is the basic principle upon how a color space works.

There are many different color space models, all of which have different methods to determine the values of Hue, Lightness, and Saturation. Some of the more familiar color spaces are the RGB scheme (for computer monitors, 3 numbers), and the CMYK scheme (for printers, 4 numbers). The RGB color space was created and is limited by the amount of colors which a computer monitor can reproduce. This explains why there are many different color spaces: color spaces are created and are suitable for different, specific applications.

Natural and Artificial Colors

Natural Colors

Natural colors are those which are derived from any natural source, such as a plant or animal. The main benefit in using natural colorings is to create an all natural product. An "All Natural" product must not use any artificial colorings. The downside to creating an "All Natural" product is the reality that these natural color compounds may be unstable under certain conditions, the most important one being pH. Even slight variations in pH can have a rather large effect on the stability of a natural color. While some of these colors hold up better than others under a wide pH range, others may not be usable at all in certain applications. Occasionally, the effect of pH might be beneficial to an end product as pH can also alter the hue and intensity of a color. Many companies take great lengths of effort to ensure that their product falls within strict ingredient and pH parameters so as to allow the use of natural food colorings in order to achieve an "All Natural" label.

Listed below are some of the most widely used natural colorings for commercial applications, all of which are available for purchase through Biosun.

Artificial Colors

Artificial colorings are man-made and are derived in a lab under strict conditions. Unlike natural colorings, which tend to have rather strict optimal performance conditions, artificial colorings are stable in practically any application and have an almost indefinite shelf-life. Due to these benefits and the fact that they are still the cheapest way to add color to a product, it is no wonder that we see artificial colorings in so many products on the market today.

There is a strict list of artificial food colorings as originally defined by the Pure Food and Drug Act of 1906 which was later replaced by the Federal Food, Drug & Cosmetic Act in 1938. Under this act, there are 7 colors which are certified by the FD&C for use in foods:

FD&C Blue No. 1
FD&C Blue No. 2
FD&C Green No. 3
FD&C Red No. 40
FD&C Red No. 3
FD&C Yellow No. 5
FD&C Yellow No. 6