U of S | Mailing List Archive | alt-photo-process-l | Re: A question about inks

Re: A question about inks



Thanks Gawain, Great information.  Jack

> From: Gawain Weaver <gawain.weaver@gmail.com>
> Reply-To: alt-photo-process-l@usask.ca
> Date: Fri, 15 Dec 2006 10:22:42 -0500
> To: alt-photo-process-l@usask.ca
> Subject: RE: A question about inks
> 
> The distinction here is probably similar to that between today's inkjet inks
> and pigment inks. Inks are much smaller, often individual dye molecules or
> very small aggregates of dye molecules (~3-20nm in size)  that are soluble
> in their medium, while pigments inks are larger aggregates (~100-1000nm or
> larger) of the same colorants, but due to their size are no longer soluble
> and so form a dispersion rather than a solution. Pigments for inkjet would
> be on the smaller side of that range, perhaps 100nm, while for offset
> printing the they might be around 500nm. The individual ink molecules in
> these aggregates are not by themselves any more fade resistant than before,
> but there are a lot more (so it takes longer to fade), and there is a
> certain added stability achieved in aggregation.
> 
> The old simplification of ink=organic and pigment=inorganic was very
> convenient, but it certainly does not apply in today's world. Pigment is
> really just an indication of a larger particle.
> 
> Gawain Weaver 
> 
> 
> 
> -----Original Message-----
> From: Jack Brubaker [mailto:jack@jackbrubaker.com]
> Sent: Wednesday, December 13, 2006 12:00 PM
> To: alt-photo-process-l@usask.ca
> Subject: Re: A question about inks
> 
> Can anyone tell what pigment dyes are?
> 
> Jack
> 
> 
> 
> 
>