shaneis

I recently heard a fantastic way to explain this to the client...

Grab a swatch of the upholstery material that you are trying to match and take a photo of it under fluorescent light, then take a photo of it under a lamp light, then walk outside and take another shot under daylight, even take another outdoors but in a shadowed area. Show these to the client and ask them which is the "right colour". It will make them see the relationship between true colour, perceived colour and light.

Hope this helps,

S.