Time for a Rood Awakening!


In 1874 (142 years ago) Physicist Ogden Rood gave a couple of lectures on ‘Modern Optics in Painting’ at the National Academy of Design. Four years later he published ‘Modern Chromatics, with Applications in Art & Industry’.

Lets back up a bit. In 1666 Isaac Newton discovered that white light could be divided with a prism in to colored light and then re-unified back into white light with a 2nd prism. He established the ROYGBIV spectrum. Funny thing though, the reason for the seven colors (Indigo really?) was to relate them to the seven notes in the octave. This won’t be the last time a brilliant mind fudged things. Turns out over the years brilliant minds like Aristotle, Da Vinci, Newton, Goethe, Albers, Wittgenstein and others have all grappled with color theory. If it’s so simple then why have so many great minds been puzzled enough to try to explain it and why are there still so many books about it?

In kindergarten we’re told that color theory is simple, that red, yellow and blue are the primaries and are all that we need to reproduce the colors we see.  We are taught: Red+Yellow= Orange, Red+Blue= Violet and that Yellow+Blue= Green, Diagram 1.



Unfortunately, it’s not that simple as there is no single red, yellow or blue pigment that make great violets, oranges and greens. We use pigments and each pigment has a chemical structure unique to itself and the interactions of pigments do not follow the simple rules of color theory.

To compensate for this we have developed a dual primary system that is dependent on two pigments each for red, yellow and blue.  One is warmer and the other cooler, Diagram 2.




While this works a little better it still leaves us with significant gaps in the available gamut and does not address a fundamental flaw in the corresponding theory- of complements.  We are told that colors opposite each other on the color wheel are complementary.  Or, that the complement of a color is the primary color not found in the original color. For example green is made from blue and yellow and is missing red so the complement to green is red. But, when we test this by mixing pigments we find that we get mud.

Our eyes see light.  We do not see the objects we see the light reflecting and refracting off the objects.

The primary colors of light* are red, green and blue producing secondary colors: Green+Blue=Cyan, Red+Blue=Magenta and Red+Green=Yellow.   Yes, red and green make yellow.

Now’s a good time to go look at your printer inks and think about how that color wheel was printed cause it wasn’t using red, yellow and blue.

We call these light complements Opponents, Diagram 4.  These light primaries are truly complementary because they complete the spectrum.




“You reason color more than you reason drawing. Color has a logic as severe as form.” – Pierre Bonnard

To be continued…

* The spectrum extends from radio waves (long) to gamma rays (short). Humans can only see a narrow section within that range from the near infrared to the near ultraviolet.

Leave a Reply

Your email address will not be published. Required fields are marked *