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The eyes have it!
November 20, 2007
I have been teaching color management to students at Cal Poly for over seven years, and in that time I have tested several hundred students on their color vision, using the Ishihara color blindness test and the
Farnsworth-Munsell Color Discrimination Test. Though both tests are of mid-20th-century origin, they have not been supplanted by newer tests. They continue to be valid methods for testing color vision.
The Ishihara Color Blindness Test, developed in the early 1960s, is used worldwide to measure the physiological color sensitivity of humans. You probably took this test in elementary school. I argue that all employees should take this test in graphic arts industries. The above samples from Ishihara show the numbers 5 and 2, respectively. People with color defects (inherited traits) often do not see these numbers at all.
Both tests are excellent in their ability to detect color vision defects, and to help in the selection of employees to make color-critical decisions. As far as I know, there is no “discrimination” when an employee is given a test to determine their (genetic) ability to perceive color, or their (acquired) ability to discriminate colors accurately. And, for many color selection, color-correction, quality control and evaluation positions, the ability to see color correctly is a critical job requirement to be able to see color correctly.
The Farnsworth-Munsell Color Discrimination Test has 85 plastic cylinders that are put in order by the person taking the test. Color discrimination measures the skill (acquired) of the person taking the test in their ability to see very subtle differences between the colors.
In graphic arts we have few life-or-death color decisions, but we certainly have a lot of business-critical color choices to make. When proofing mail-order catalogs, fabric samples, paint samples, and nearly every color-critical printed project, the ability to see color correctly will make a huge difference between success and failure in the printing plant. It makes sense to test the color vision of every incoming employee to keep as a record of their ability to see and discriminate between colors. When a position opens, the employee can be evaluated for fitness to perform color-critical tasks, and passed-over if their employee records show them to be color-blind. The job can be given to a person with better color vision.
There is a difference between color-blindness and an inability to discriminate between colors. Most color-blindness (usually referred to as being
color-defective) is genetic. 6.0001 percent of men have inherited color defects, while only 2.001 percent of women have the same inheritance (follow the
X chromosomes!). I know you have probably heard or read much higher numbers, but those are apocryphal; these figures come from an authoratative tome entitled
Medical Genetics, 5th ed. by Michael Connor, and Malcolm Ferguson-Smith, Oxford University Press, U.K. My work shows lower numbers. I have tested about 480 students, and have encountered a total of three young men who show significant color defects.
But here is an anomaly: of my current 43 students of Color Management and Quality Control, two have measurable color defects (red-green color-blindness). The remainder have “normal” color vision, and they have extraordinary color discrimination skills. The general population tends to score as follows on the Farnsworth-Munsell Color Discrimination Test:
“Superior” color discrimination 16%
“Average” color discrimination 68%
“Poor” color discrimination 16%
My students score much better than the general population, so much better that I have a fascinating challenge.
I need to find out why. These are the data for my students (the two color-blind students were excluded):
“Superior” color discrimination 47%
“Average” color discrimination 53%
“Poor” color discrimination 0%
Is it that these students study color daily, work with color daily, make color decisions daily, and are thus able to put 85 colored cylinders in proper order better than most of the population? Is it that young people with superior color discrimination enroll in graphic communication? Is it chance? (It’s not; I have been seeing similar results in this test for years, and have been scratching my head continuously in wonder.)
In any event, my students are better-suited to working in positions in the graphic arts that require superior color skills. To make a control group for the analysis of this strange situation I have asked for non-graphic arts student volunteers to take the same tests as my students. Last week a young man volunteered his fraternity. So, early next year I will be testing a group of about 40 young men (only one is in graphic arts) to see how they perform on the same tests. The results will be very valuable and informative. I will provide pizza in exhange for their participation in the test series.
In a printing plant it’s critically important to know that assignments that require accurate color vision are given to people who have the physiology and the skill to do the job. I am grateful that my students have chosen to follow careers in our industry. With their exception vision, I know we’re in good eyes.
Posted by Brian Lawler on November 20, 2007 | Comments (4)
