Color us correct, mostly
I really appreciate Stephen Regenold's informative article on projector color in the January issue ("Color Correction Blues"). I agree that most presenters are not prepared for the widescreen age, but I believe that when the presentation field discovers the advantages of widescreen over the 4:3 standard, the move to a higher aspect ratio will take off. For example, the most restrictive parameter for projection is all too often ceiling height, [whereas] the one dimension that nearly always has growth potential is width. Thus widescreen [16:9 aspect ratio], for business presenters, can actually be more efficient and effective than 4:3.
Richard Travis Florida State University Tallahassee, Fla.
I agree with much of what [Stephen Regenold] says about contrast ratio in his article, "Color Correction Blues." As a video engineer, I am equally entertained — or perhaps disappointed — with all the contrast-ratio hype. [One factor you did not address] is that most people are not aware of the significant limitations of the optical devices being used to perform contrast-ratio measurement. All optical measuring tools have a difficult time [measuring extremely low light levels]. Consequently, values of 3,000-to-1 are easy to obtain in a dark room in which the light from the screen may be barely above the minimum sensitivity of the measuring instrument.
In addition, the human eye contributes tremendously to our perception of contrast ratio as well. Physiologically, the eye has a dynamic range of about 100-to-1 at any given time due to its adaptive nature (the opening and closing of the iris to manage light exposure on the retina). In scenes having a higher ratio of bright area to dark area, the iris will close down, enhancing our perception of contrast ratio, when in fact nothing about the projection device has changed — and vice versa. [Either way, the eye's dynamic range of 100-to-1 remains the same.] Under these conditions, the contrast-ratio spec for the projector holds virtually no meaning because there may not be enough dynamic range in the image to support a high ratio.
What does all this mean? It's another way to explain just what you proffered in your article. Any display that can consistently provide the minimum contrast ratio the eye is able to resolve, at any given time, has enough contrast.
Steve Somers, V.P. of Engineering Extron Electronics Anaheim, Calif.