405nm looks blue on white cotten

[cmg5461]

Does anyone know why this happens? I've taken a wave physics course and I can't seem to figure it out o.o

It only happens on white cloth. Not dark cloth. Not white doors.

 

[Blord]

The washing powder contains a chemical that is fluorescent. This means that it absorbs 'invisible' UV radiation and re-radiates it as 'visible' light. Therefore the washing will not only reflect visible light, but will also emit some 'extra' visible radiation. This means that white sheets almost appear to glow white if held in sunlight and are deemed to be 'whiter than white'.

 

[cmg5461]

The washing powder contains a chemical that is fluorescent. This means that it absorbs 'invisible' UV radiation and re-radiates it as 'visible' light. Therefore the washing will not only reflect visible light, but will also emit some 'extra' visible radiation. This means that white sheets almost appear to glow white if held in sunlight and are deemed to be 'whiter than white'.

Makes perfect sense, thank you!