Bull!

[blue-j]

At http://www.imagemagick.org/Usage/color_basics/#intro the statement is made that "...some animals see movement far better than any specific color (such as a bull, who contrary to popular beliaf can not see red, only black and white)..."

This is not entirely true. Bull vision is dichromatic, with sensitivities around the blue-violet and green wavelengths (S-cone: 444–455 nm; M/L-cone: 552–555 nm).

http://www.neitzvision.com/content/publ ... sNeuro.pdf

[anthony]

I stand corrected about the black and white (updating page), but they certainly can not see red! It is the movement of a bull fighters cape they react to.

The main point however stands. video images are for human use. Do not expect some other animal, (or alien ) to understand our artificially generated images. they may see something, just not what we see.


This was highlighted to me in two classic Sci-Fi books.

• Bug Wars -- whcih has no human characters at all. Some lizards with color vision (to help fight the bugs that also had colro vision) complained to their superiors (with monochrome vision) that their secret camouflaged base was not only visible but stood out like a bright beacon!
• First Lensman -- by E.E.Doc.Smith when a human visits a world filled with garish mix-mash of colors that did not make any sense until he saw through alien eyes as being advertising in a completely different spectrum of color.