Why do colored paints and colored lights mix differently?
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After you watchWhy do colored paints and colored lights mix differently?
The short answer
Lights add their contributions, while pigments absorb and reflect parts of incoming light. Balanced RGB lights can look white; changing one channel changes the color. Pigment mixtures depend on the actual pigments and amounts.
The whole story
How it works
The hidden display uses normalized RGB contributions [1,1,1] versus [1,1,0.5]. The same channel amounts drive the numeric labels and colored spots in normal and calm modes. The earlier paint activity is a simplified filter model, not a prediction for all real paints.
What people get wrong
Including red, green, and blue does not guarantee white. Their relative intensities must be balanced. Mixing any set of paints also does not always produce brown.
The catch
Light mixtures depend on channel intensities and the background. Pigment mixtures depend on their absorption, scattering, amounts, illumination and surface. Mixing all paints does not always make brown.
Questions kids ask
Why do colored paints and colored lights mix differently?
Lights add their contributions, while pigments absorb and reflect parts of incoming light. Balanced RGB lights can look white; changing one channel changes the color. Pigment mixtures depend on the actual pigments and amounts.
What is different in the hidden experiment?
After exploring additive lights and illustrative pigment filters, predict the color of a new unbalanced light recipe: red 1, green 1, blue 0.5. Compare against balanced RGB through visible per-channel steps.
What limit should I keep in mind?
Including red, green, and blue does not guarantee white. Their relative intensities must be balanced. Mixing any set of paints also does not always produce brown.
Talk about it
- Before running the hidden experiment, explain your prediction.
- Compare the final picture with your prediction. Which visible change supports your explanation?
- What did the experiment keep fixed?
For grown-ups
The hidden display uses normalized RGB contributions [1,1,1] versus [1,1,0.5]. The same channel amounts drive the numeric labels and colored spots in normal and calm modes. The earlier paint activity is a simplified filter model, not a prediction for all real paints. Including red, green, and blue does not guarantee white. Their relative intensities must be balanced. Mixing any set of paints also does not always produce brown.
Keep going
What else makes you wonder?
- If three lights make white, what do red and green alone make with no blue?
- Why does a printer need a separate black ink if it already has color inks?
- When a screen shows you the color brown, is it adding light or taking it away?
