[cath walford]

catherine wells  asked the Naked Scientists:
   
Hi,
 
Is it true that if you just get a tin of paint and paint something it'll change how that object reflects back light? I recall hearing that black has deep fibres (?) that the light enters and then gets caught up in and can't get out of again (someone on your show talked about making the darkest black ever that trapped all light in it). 

How can this be true if the paint is the same consistency?  
 
Many thanks,

Cath

What do you think?

[lancenti]

I don't think the object itself changes how it reflects back light, but rather you apply a surface which reflects light differently (i.e. absorbs different wavelengths). Since you don't alter the original object chemically, then it doesn't make sense that it interacts with light in a different way.

[cath walford]

Hi,

Thanks for this, but it's not quite what i meant.  Obviously the way the object reflects light won't be changed, but what i mean is: as paint is the same consistency, how can black paint reflect light differently than red paint?  Or a jumper that's dyed blue reflect differently than a green one?  The object has the same texture, so what is it in the dye or paint that changes how light is reflected? 

Many thanks,

Cath