Contrast Part 4: ………………… Luminosity and Lightness

Yesterday looked at describing and measuring color. Today we consider tones. When it comes to contrast, tones are where the magic is made in our images.

Part 4 of a  series

“All About Image Contrast for Photographers”


Just as contrast itself comes in several “flavors”

1. Tonal contrast

2. Color contrast

The same is true of lightness (brightness)

1. Measured by a device (light meter for example)

2. Perceived by a human’s vision system

Since brightness is “the stuff from which contrast is made

It’s important to understand how it is

Measured (and perceived)

If we want to control contrast in our images.


Imagine Monet at a green field of red poppies palette in hand

and you at his side with your camera

Click to enlarge

6-13-2013 12-45-08 PM

Luminosity & Lightness

We need to know how to display lightness in its several forms

Further, we need to know how to adjust the resulting contrast

For example – how to get from #3 to #4, if we were Monet

(Being able to change 3 to 4 in post-processing is a key to making magic)


The significance of equiluminance was discussed in part 2

This painting by Monet was used as an example

Monet – Impression: Sunrise

Note the sun vs. its background

Wildly different hue, but

Equiluminant


 In the next part –

How to adjust brightness

Both perceived and actual

(Ansel’s dodge & burn changes the perceived portion;

how can the actual be changed?)

Also, closely related, different B&W conversions, e.g.

The conversion that shows perceived lightness (grayscale)

Is not the one to display luminosity

(Hajo, This is related to our long series of comments in a recent post)


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