Does color really exist? Or is it merely the lack of lack of some chemical in the makeup of an object that allows light to reflect a certain “color” into our eye?
During the course of Alan Gilchrist’s book, Seeing Black and White, Gilchrist talks about the “perception of surface color, which is the property of an object”. In other words, he looks at how light is reflected off objects and directed to our eyes, where we see color. The makeup of the object is what determines color. A brief history highlighting discoveries and people focused on lightness starts in the 19th century and ends during the computer age. Gilchrist continues his dialogue on lightness with topics like anchoring and errors regarding perceptions.
Gilchrist identifies four different terms within his text that change the way we think about objects and light. The first term, distal stimulus, refers to actual objects – physical items that on the earth that reflect light. One way to remember distal stimulus is to think distance (distal – distance). Objects have a certain distance away from you. It might be a very short distance, but it is still not part of you – the person seeing the object. Proximal stimulus is the process in which light travels and reaches sensitive areas of the eye. Proximal stimulus is where distal stimulus meets you, an organism seeing the object. These two terms are related to each other by more then just the common word.
Edward H Adelson's Checkered Square illusion (MIT)
Another term introduced is percept. “What you see is NOT ALWAYS what you get.” WYSIWYG is a commonly used phase when talking about page layout and website software. Here I have changed it a little to help represent the word percept. Our eyes have a tendency to play tricks on us and percept is the term to explain this. Gilchrist goes on to explain the difference between brightness and lightness. At first glance these two terms may appear to have the same meaning, but they don’t. You can say that the sun is bright, but you cannot say that they sun has great lightness. Brightness refers to the actually light coming off an object, while lightness refers to the surface properties of an object.
As Gilchrist mentions “contrast often refers merely to the ratio (sometimes difference) between the luminance on one side of an edge (or gradient) and the luminance on the other side.” This same definition applies to tone. My Design Theory class has defined tone as neutral/grays. In Gilchrist’s definition of contrast he talks about the difference between one side to another. Tone relates to the middle transitional area. His definition expands of contrast expands tone to mean so much more.
The Introduction to Seeing Black and White seems short, but it has so much information that you are dumbfounded by how much you may not know about seeing objects. From distal stimulus to proximal stimulus (the object and the process), Gilchrist takes the reader on an insightful journey into lightness and how humans perceive it. The difference between lightness and brightness is an important distinction that Gilchrist makes in the introduction. Optical illusions, or percept, are an everyday occurrence that Gilchrist tries to explain, or at least make us more aware. It would be interesting to continue reading the book and discover what errors have occurred when we humans try to perceive things. In many ways, I think as humans we look to look. What would happen if we start to look to see/understand? A curious question with even more curious answers. Hum… things to ponder.
