Digital BW, The Print

Clayton Jones wrote:

>>Unless the fact that the 'color' is mixed with the 'carbon' has the 
>>effect of somehow inhibiting fading, the 'color' is still going to 
>>fade, giving the same overall image degredation.  Granted, in the 
>>non-mixed application, individual color dots would fade, while the
>>carbon would not.  While in the 'mixed' environment each dot would
>>fade/change color.  But, the overal result should be the same?
> 
> 
> Good question.  I have two thoughts about it:
> 
> 1) In a RIP print a Cyan/Magenta dot is a fully exposed batch of that
> ink.  In a mixed carbon ink the microscopic pigment particles are
> surrounded by carbon particles, so maybe the pigment particles are
> offered some protection by the surrounding carbon on that microscopic
> level...

The composite grey is build in another way, that's what I wrote 
in the message before this one.

The more the carbon protects, the less toning happens ......... 
You have to increase the colorant to get more toning but by that 
the colorant gets more exposed.  Like giving a black ink a tone 
.... better start with a heavy colored ink and add black than the 
other way around. That's the silkscreen printer in me who writes 
this.

> 2) Because of the mixing on the microscopic level, I wonder if the
> desired print toning can be achieved using less pigment?  This seemed
> to be what Bob was implying.

I think that Bob is implying that he can use single hue, more 
opaque, pigment particles for the toner while the colour printer 
has to lay down two hues at least that have to be transparent and 
must make a wide colour gamut for their normal task. The opaque, 
low gamut, pigments are just more lightfast. Compare the first 
Roland ink pigments with the pigments that were introduced by 
Generations later on etc. The Roland pigments last longer 
outdoors but their gamut is much less. C.D. Tobie called them 
prefaded :-)   Paul Roark has his doubts whether the modern wide 
gamut pigments like Ultrachrome really are pigment only. But 
without doubt they are not that fade proof as the pigments used 
for outdoor exposure. The last can still be used for the humble 
task of quad toning.

Microscopic in this context is still way bigger than lightwave 
lengths/photon sizes so there's no reason that something 
specially happens with light filtering in that sense. There's 
however a difference between laying down different colored 
droplets more or less next to one another and laying down 
homogene grey "toned" inks.  That's what I described before.

Ernst