Color Attainability
[Author: Text & Illustration: Bill Fischer]
Overview
Production methods, environmental influences, proximity to other colors, and human sensory variation all affect how we perceive color. Universal design principles call for color choices that provide the maximum attainable quality across all of these factors.
Production Limitations
There are several ways that color is produced and reproduced. And, each has its own capabilities and limitations. Primary color systems are human constructs and have no foundation in the laws of physics or biology. However, the achievable range of color for any construct is affected by how physical light creates color coupled with the biological limitations of the human eye.
RGB Color System
RGB (red, green, blue) are the light-emitting, additive primaries utilized by digital devices to create colors. This system has the broadest color gamut (number of produce-able colors that can be sensed by the human eye) and can produce the most intense colors. Red, green, and blue are also the colors of the light sensing cones in the human eye.
CMYK Color System
CMYK (cyan, magenta, yellow, black) are the light-reflecting, subtractive primaries used by common off-set and many digital printing processes. Cyan, magenta, and yellow are used because they are lighter colors than red, green, and blue. This provides a larger color gamut in a reflective system. However, the color gamut is narrower than the RGB additive system.
RYB Color System
RYB (red, yellow, blue) are the light-reflecting, subtractive primaries initially defined by fine art painters prior to the development of modern pigments. Though it offers the narrowest color gamut, it persists in educational environments. Students would be able to achieve better color mixing results with any physical media using CMYK colors.
Custom Color
There is a vast array of custom color applications that include ink, powder coat, paint, anodization, and a variety of other chemically induced surface treatments. Since the goal of these colors is, typically, to stand-alone, without the burden of being part of a color system, they are limited only by their individual production methods.
The RGB Color System and Over-saturation
RGB Color systems, those used by computer displays to make color, can facilitate the use of highly saturated color combinations. These can cause scintillation and vibration at the edges of graphics, which makes them harder to focus on.
The CMYK Color System Maximizes Usability
Using the CMYK Color system has the built-in effect of limiting color saturation, avoiding vibrating edges, and overstimulation when used in combination with other graphical elements.
It has the added benefit of creating art and design that will minimize color shifting between digital and print production methods.
Situational Limitations
Color does not exist in a vacuum. It's profoundly affected by the environment in which it finds itself. Color combinations that hold up in a variety of conditions utilize high contrast to each other and their surroundings.
Substrate Variation
High C = high contrast
In the case of printing ink on paper, the type of paper can profoundly influence the color. On the left, in the image above, vibrant colors are obtained using high-gloss paper. On the right, colors are subdued dramatically when applied to matte paper such as newsprint.
Light Variation
Low C = low contrast
The digital display on the left demonstrates the color dulling effect of a low-light-energy-saving mode. On the right, glare from direct sunlight can wash out the brightest digital display.
Environmental Effects
A yellow chair in a yellow room could be a difficult object to find, let alone sit-upon for a sight impaired person.
Environmental Effects
Objects that are complimentary (opposite) in color to their surroundings will allow them to be seen and therefore easily accessed.
Physiological color Deficiencies
These are uncorrectable, physiological, vision deficiencies that affect about 40% of the population.
Color-blindness: 4.5%
Low Vision: 1%
Photophobia: 20%
Scotopic Sensitivity Syndrome: 14.5%
Color-blindness
On the website Colour Blind Awareness (external link), "Approximately 40% of colour blind pupils leave school unaware that they are colour blind, 60% of colour blind people are likely to experience problems everyday and yet often not realise the full impact."
According to Color Blindness Facts and Statistics (external link) and the Colorblind Guide (external link) the percentages of color-blind persons breaks down as follows:
Total All ages: (4.5 %)
8 % of men
.5 % of women
Deuteranomaly: 2.7% (green is weak)
Deuteranopia: .67% (green greatly reduced)
Protanomaly: .58% (red is weak)
Protanopia: .55% (red is greatly reduced)
Tritanomaly: .0002% (blue is weak)
Tritanopia: .0001% (blue is greatly reduced)
Achromatopsia: .00003% (no color vision)
Red-green color-blindness accounts for 99.99% of cases. These are called Deuteranomaly, Deuteranopia, Protanomaly, and Protanopia. Deuter- and Proto- conditions are similar and are both regarded as red-green color-blindness. Trito- can be thought of as yellow-blue color-blindness.
Photophobia
According to a study published by the NIH (external link), Photophobia is a common yet debilitating symptom seen in many ophthalmic and neurologic disorders. It is estimated by the NIH that up to 20% of the population may be affected during their lifetime.
Women are 2-3 times more likely than men to experience migraine accompanied by photophobia according to another study published by the NIH (external link).
It is defined as an abnormal sensitivity to light, especially of the eyes, and is reported in most all forms of migraine and many neuro-ophthalmic disorders.
Persons with this condition can experience discomfort and flickering from images and text containing high saturation. They will often use accessibility features on digital devices that dim the brightness or convert screens to grayscale.
Scotopic Sensitivity Syndrome
This neurological condition is often referred to as Irlen Syndrome or the Meares-Irlen Syndrome after Helen Irlen and Olive Mears, two educator/researchers that independently discovered the condition. It is sometimes associated with dyslexia, however a study performed by Isla Kriss and Bruce JW Evans (external link) has identified it to be a separate condition. Additional research can be found at Irlen: Irlen and the Brain (external link). It is estimated to effect up to 15% of the population.
Symptoms associated with Scotopic Sensitivity include Sensory overload caused by surface reflection, patterns, and high contrast graphics (over 16:1 ratio) resulting in fatigue that can interrupt reading and math comprehension, as well as deter computer usage.
Low Vision
According to the National Institute of Health (external link), Low Vision is defined as 20/40 or worse vision with best possible correction. It affects approximately 1% of the population.
Causes can include: Age-related macular degeneration (AMD), Cataracts, Diabetic retinopathy, Glaucoma, and Genetics.
