Eléonore Delisse's Day and Night Light was designed to tackle wintertime blues

Design Academy Eindhoven graduate Eléonore Delisse has created a lamp to counter seasonal affective disorder by displaying different colours at different times of day

Delisse's Day and Night Light uses different wavelengths of light to create varying colours, intended to help regulate the body's circadian rhythm.

Changes in this rhythm triggered by falling lights level in autumn and winter can cause seasonal affective disorder (SAD) – a cyclic form of depression that affects millions of people every year."The ultimate wellbeing is to wake up happy and sleep peacefully at anytime of the year," Delisse told Dezeen. "And yet winter blues play a big role in our mood."

Delisse designed the lamp as her graduate project at Design Academy Eindhoven, in response to what she saw as the lack of considered, design-led solutions for SAD.

"All the existing solutions to SAD focus on the intensity of light," said Delisse. "I was interested to look at this from another perspective. Not only by being only exposed to certain lux levels but by having a coloured rhythm that influences your brain behaviour."To create the different colours, the LED light source embedded in the lamp's pear-wood body shines through a rotating glass disk. The glass is dichroic, so it displays different colours in changing light conditions or depending on the angle of view.

Suspended on two brass fixings and powered by a motor, the disk rotates to coincide with different times of day, altering the colour of light it reflects.

"Different colours of light affect the body in different ways," said the designer. "The Day and Night Light is a device to understand time differently and regulate our circadian cycle accordingly."

A blue light in the mornings lessens the body's production of the melatonin hormone that stimulates wakefulness, while an amber light in the evenings triggers melatonin production to make the user feel sleepy.

The light source is hidden in the curve of the lamp's body, which is slotted into a block of marble to weigh it down. The flat piece of wood has a half-circle removed so the glass disk can rotate freely.