Contrast & Vision – Part 1

Some essentials related to contrast and human vision. Important to understand how this affects your images and, in turn, a viewer’s perception of your images.

Understanding the nature of light

Is essential to understanding contrast

Understanding the role of contrast in human vision

Is essential to understanding how (& what) we see

And so we begin….

Click to enlarge for detail

6-4-2013 1-22-23 PM

 Top Row: Color Capture ….. B&W Capture

Bottom: Capture with Enhanced Contrast

Without increased contrast, the texture is nearly invisible

The camera captured it, but it took added contrast to bring it out

If you want to show texture, tonal contrast is needed


What do our eyes see?

Our eyes see light & its components which include

Color and

Tone (brightness)

They are receptors for visual stimuli


What happens to the signal received by our eyes?

It is sent to the brain for processing

The combination of eyes + brain = the vision system

Flaws in either part will affect what we “see”

Eye: A common “eye flaw” leads to color blindness

Brain: Dyslexia is a problem originating in the brain

Skipping one or two small details 😉

The brain relies almost totally on contrast

To complete our vision (seeing)

If there is no contrast for our eyes to discern

The brain will not “detect” anything and

We will see nothing

The better the contrast, the better we see


Is everyone’s vision system the same?

Not everyone sees (interprets)

Identical colors or tones to be the same as the next person sees

(and your dog sees everything in black & white)

The point is that there is no “one single color & tone”

When it comes to what human vision (eye + brain)  “sees”

Even when presented with identical stimuli

It’s important to realize that not everyone will see your image

as you saw or captured it

Don’t assume that they do

(And that doesn’t even consider the role of emotion)

It’s a common joke about referees being blind

How about color-blind photo judges?


Even you, as an individual, will misjudge colors and tones

Depending on their physical surround

Further, you will respond differently to the same image

from time to time, depending things like

Your mood, your culture, ….

———————————

Do the two reds “look” the same? The greens?

(Apologies to those who are color blind)

They are the 100% identical, but appear to be different because of the

Contrast difference (B&W) of the surrounding space

6-3-2013 11-14-46 AM

———————————

Is the tone (brightness) of all three ovals the same?

Again, as in the above color example –

They are identical in tone, but appear to be different because of the

Contrast difference (B&W) of the surrounding space

6-3-2013 11-22-24 AM

Are you beginning to think – Contrast really makes a difference!

It does and may be the most important difference between a good & great image


The examples suggest that there are (at least) two forms of contrast –

Color contrast

Tonal contrast

(as well as absolute & relative contrast)

Which makes a good stopping point and segue to tomorrow’s post


Enter your email address to follow this blog and receive notifications of new posts by email.