Gilchrist's -Seeing in Black and White

After reading Gilchrist's introduction to Seeing Black and White what I gather from the introduction chapter was color perception, the perception of surface color, and human perception as opposed to machine vision.

The author describes that the contents of his book deals the humanistic ways of seeing. Either through reflectance, illuminance, lightness, brightness, and types of surfaces. Perception is the main topic from what gather from this book. Below is an attempt to define the some of the basic principles of seeing.

Distal Stimulus to me means the way light reflects off of a surface. Light reflecting from angles or directions can differ in amount on a matte surface or a glossy surface. A matte surface is a dull type surface and light reflected off of this type of surface is the same amount from any direction. As opposed to the matte surface, the glossy or shiny surface reflects light at an angle. Neutral or achromatic surfaces reflect the same percentage of light at all wavelengths as compared to matte and glossy surfaces.

Proximal Stimulus is described as where the pattern of light reflected from a surface meets the eye also referred to as retinal image. The intensity at each point of an image is called luminance. This can be confused with reflectance which is percentage, luminance is the intensity of light just before it hits the eye.

Percept is the way a person sees or perceives an object. One may perceive an object one way but in actuality it is a whole different look. This could be due to it's lightness or perceived reflectance.

Lightness and brightness differ in meaning according to Gilchrist, he states that both lightness and brightness are perceptual terms, only lightness refers to the perception of an objective property of a surface or its reflectance. Brightness refers to the perception of a proximal stimulus or the raw intensity of some part of the image hitting the eye .

Lastly, contrast can and has been used differently. Some refer to it as a ratio or difference between a light and dark color on a surface . Gilchrist describes this as contrast as an illusory phenomenon. Or better yet, the way complimentary colors on a color wheel is set up to show a color straight across from another color to be the most contrasting combination. At least that's the easiest way I can explain contrast. Gilchrist also describes contrast as a theory meaning a perceived darkening of a surface when it is placed on a brighter surrounding surface. More of a visual contrast of light and dark when placed next to each other.

What I took away from the introduction portion of this book is that there is a lot of thought or theory behind seeing colors. While reading this portion of the book, I knew what Gilchrist was talking about but I have never thought about the theory behind it all. I now know that I will see things in a new light when it comes to making color choices for what ever I will be designing. It will be a huge tool in my arsenal of design.