Kochu Studio Light experiments

Study 11 Thin films

Optical study 11

Iridescent Plate

Across the surface of Red Meridian, a second colour appears as the light changes angle.

Red Meridian on warm plaster. A green and blue sheen crosses its red field, ochre disc, and dark crescent.
Red Meridian in reflected lightDigital optical study

Viewing controls

Catch the reflection

The coating reflects different wavelengths as you change its thickness or tilt the light.

Thin-film settings
28°

Measured from the surface normal. Use the arrow keys to change the angle.

205 nm

Nominal coating thickness. Zero shows a bare substrate. Use the arrow keys to change thickness.

Reflected spectrum

The spectrum is available with the live plate.

Recorded views

One painting, three reflections.

At a steeper angle the blue spreads down the crescent. At the original angle, a thicker film brings a pink sheen across the red field.

First light, with a green-blue ribbon crossing the middle of the painting.
First light28° / 205 nm
Oblique light. The blue-green reflection moves downward across the ochre disc and dark crescent.
Oblique68° / 205 nm
Thicker coating, with pink and lilac along the same ribbon.
Thicker28° / 267 nm

Source painting

Red Meridian

The simulation uses the photographed painting. The coating and lighting are illustrative.

Read the method
Original photograph of Red Meridian on its easel. An ochre disc sits inside a red field between a green leaf and a dark crescent.