[connorboyle]

> Images printed with structural colour ink can be made both highly transparent to transmitted light (top) and at the same time reflect light from above in vivid colours (bottom)

Probably a foolish question, but wouldn't there be some unavoidable loss of brightness to the transmitted light, unless the structured color somehow "knows" to transmit light in one direction and reflect it in the other direction (which seems impossible given that it is printed by an inkjet)?

[watersb]

(Not an answer to your question, just a note that "top" and "bottom" refer to the illustration in the article -- the authors printed a printed a vivid color logo on what appears to be a smartphone screen. With the screen on, the image on the display shines through the design printed on top.

That might be a neat effect on the glass roof of a car.)

[sitharus]

Structural colour works by destructive interference of reflected light. It requires the light to be scattered for this effect, so light travelling through at 90° won't be affected.

On the image in the article you can still see a trace of the image on the active screen from indirect light.