Wednesday, December 8, 2010


HERE IS A sample image, which shows the four channels of a CMYK image. Use your knowledge of CMYK to determine some facts about this image.

If you haven't read them yet, you may first want to read these articles: Color Spaces, Part 2: CMYK and Part Two of "Color Spaces, Part 2: CMYK".

Quiz - CMYK

This sculpture of an acorn is found in Wydown Park, in Clayton, Missouri.

I am convinced that a thorough knowledge of the channel system of digital images is essential for good photography. By looking at a color photograph, you ought to be able to imagine which each color channel ought to look like, and by examining the color channels, you ought to be able to determine what colors are represented.

The CMYK color system represents inks printed on a page, and includes the colors cyan, magenta, yellow, and black. Each channel represents one color of ink. No ink is placed on the page where the channel is white; and where the channel is black, we have 100% ink coverage. For example, a bright cyan-colored object will be black in the cyan channel, and white in the other channels. Where we happen to have roughly equal quantities of cyan, magenta, and yellow ink, the CMYK system will subtract those colors and replace them with black ink. So K (black) will dominate the shadows.

Here is your task:
  1. Identify each color channel in the image above.
  2. There are two colors of flowers in the image. Identify the colors.  We have taller flowers which can be seen in front of the acorn, and shorter flowers of a different color in the foreground.
Unlike my last quiz, I won't give you any clues. Use your knowledge of nature and the channel structure of CMYK to determine the answers.

1 comment:

Mike said...

This is a toughie!

From top left clockwise I'm guessing
- C
- K
- M
- Y

short flowers are yellow, tall ones are magenta?