If yellow light is shone on the red ink dried on the glass plate, what color is transmitted? What color is absorbed?

1 Answer
Mar 18, 2017


If we have a perfect red ink and a perfect yellow light, nothing will shine through, and everthing will be absorbed.


Red will only let through red light, and absorb all other colours.
Since the yellow light contains no red, there is nothing to transmit.

In practice, the red ink will have its highest transmission in the red region, but will transmit some light of the wavelengths nearby.
And yellow light may contain some wavelengths that overlap with the 'transparency' of the red ink. The transmitted light may look orange-like.

So the statement at the top is only valid for perfect red ink and perfect yellow light.