Digital BW, The Print

Joost Horsten wrote:

>> Any change in the surface of matte black should give different 
>> readings.
> 
> I come to that conclusion as well. It's not illogical. My explanation 
> is that any contamination or damage increases the scattering at the 
> surface and, by that, increases the reflectivity of the surface. Is 
> that what you mean as well? But I'm surprised by the size of the 
> effect.

Given the up to 0.6 D differences between matte and gloss 
prints (with PK) it can be expected. A superb gloss top coat 
applied on a textureless matte print (with MK) will  show 
similar differences. It is the well known effect you get with 
spot varnishing on a matte or semi-gloss black offset print. 
Different visual density and a more selected view angle for 
the deeper black of the varnished area. So the grease 
(varnish) or marks (texture is reduced like in paper 
satination) reduce the scattering and the spectrometers 
light/sensor geometry results in less light reflectance to the 
sensor itself as it isn't in the the direct angle of reflection.

Once we had a discussion here on the differences between dye 
ink matte Dmax and pigment ink matte Dmax. That's a harder nut 
to crack.

Met vriendelijke groeten,   Ernst


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