Understanding Contrast part1: Gamma

Neil January 29th, 2008

Welcome to my series on understanding contrast.

Defined by dictionary.com: Understanding defined in the realm of Philosophy.

  1. The power of abstract thought; logical power.
  2. Kantianism. the mental faculty resolving the sensory manifold into the transcendental unity of apperception.

I love Kant’s creative use of verbage: the mental faculty resolving the sensory manifold into the transcendental unity of apperception.

I’m not talking to wimpy vague or basic knowledge of contrast. I’m talking about the pure verb of ‘understanding’=the power, of abstract thought. I want to inspire you into resolving the sensory perceptions of your excited artistic manifold perceptions into the transcendental unity of expression. Let’s get down in the nitty gritty past our misconceptions, half-

Gamma, baby yea! (say it out loud in your sexy Austin Powers voice)

p.98 of Dan Margulis’s Photoshop LAB Color —

“The answer to these stimulating questions is the gamma setting. A gamma of 1.0 would mean that the midpoint is exactly halfway between the two extremes, in the opinion of a machine. Most color theoreticians don’t like that structure. They feel, correctly, that human beings perceive more contrast in dark things than in light ones. Therefore, at a gamma of 1.0, the difference between 200R 200G 200B, a very light gray, and 195R 195G 195B will be percieved as a smaller diference than between, say, 100R 100G 100B and 95R 95G 95B. ….This heinous lack of perceptual uniformity, in their view, justifies a fudge factor. The midpoint, they feel, should be defined as a darker grey than the machine would like. ….Therefore, values darker than 128R 128G 128B will be packed closer together than before, and those whose lighter will be further apart. More values are now being devoted to portrayal of dark colors and fewer to light colors….”

We will delve deeper into this topic in Chaper 13….

Well I didn’t start out with ‘this is what contrast is’ because I don’t think you’d get it without wiping away some of the misconceptions that are haunting you and keeping your vision tied up. So let’s get something straight - your eyes don’t see things as they are. Your eyes adjust things to emphasize the shadows.

In sRGB, with it’s larger fudge factor, it’s a darker 54L0A0B. Think about these two numbers, and a surprising secret comes slithering out from under a stone. Neither of these two artifically darkened RGB midtones is as dark as 50L.

Your eyes don’t see things as they are - your eyes adjust things with a midpoint that’s not in the middle creating a gamma of something near 2.2

I think there is a lesson and an observation in the above paragraph and the deeper roots of color theory that go into making the computer systems that we use. First, the observation: “human beings perceive more contrast in dark things that in light ones.” I believe the lesson we need is one in opening ourselves to the transcendental unity of apperception - opening ourselves to the foundation of understanding itself. Another definition of understanding I found says “sympathetically aware of the character or nature of“.

How sympathetically aware are you of your camera’s subjects?

I don’t say ‘Understanding the Darkness to See the Light‘ carelessly or because it’s catchy.  I say it with a firm backing of color theory and the psychological underpinnings of human perception - which we’ll delve into as this series develops.

Finally, the lesson from Gamma that we should take to heart. Our eyes manipulate our surroundings - and so we can feel free to manipulate our images. Maybe so subtly that our eyes assume no manipulation - but hopefully so perceptively that the awareness of our subjects is fully realized.

Introduction to Understanding Contrast Series

First off a tip of the writer’s hat to my college Michael Reichmann who so many times has opened my mind to the underlying reality of photographic image making, I credit his understanding series as a thematic example upon which I will build this series on contrast.

Second, this series is an inspirational and informational introduction to the very powerful workflow action that I will be releasing soon. If you appreciate the thinking in this writing, you will be pleased with the power that is put at your fingertips with this action, and it’s training materials will give you renewed appreciation of this series.

Third, this series is a response to many of the ungrounded and ‘copycat’ threads and questions I see around the internet from time to time. The tendency is to try and reproduce a style or look, instead of digesting how the subject matter interacts with a treatment to produce deeper understanding. Don’t get me wrong this isn’t negative, I learn by copying too, as have artists from all generations. I hope this article fully articulates the full process of deconstruction rather than a few photoshop steps as what I have learned on the backside of copying so that I can create better.

Have you any favorite copycat threads? Post links in the comments and I’ll check them out and discuss in the future contrast posts.

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