Lightness and Brightness

[tomczak]

Is square B much lighter than square A?

[MikeG]

Had me fooled!
Mike.

A&B-1.JPG (5.72 KiB) Viewed 4121 times

[keithrj]

Looking at the readout tool these squares have exactly the same RGB values! One of those optical illusions - very good!

[doug]

This image (optical illusion) is used in a video on the website for the WhiBal white balance card. As I recall, the video includes other optical illusion demonstrations that are designed to demonstrate that you can't always trust your eyes when it comes to determining colors or tones. I did acquire one of these cards and when it is included in a test shot under difficult lighting conditions, I use the midtone eyedropper on it in the color balance transform in order to set the white balance adjustment for all shots in that lighting environment. Are there other and better ways to use such a white balance device with PWP?

The video is here
http://www.whibalhost.com/_Tutorials/Wh ... index.html

Doug Haag

[tomczak]

In the similar vein, but an actual image... There is an interesting white anchoring idea in the psychology of vision - generally proven by several experiments, though people still argue about details, plus there are exceptions (e.g. size and shape matter).

[Andreas]

IMO it shows what can be done with (intelligent) local contrast enhancement.