RE: A question about inks
Interesting information. But what determines if a particle will go into solution rather than dispersion? Is this purely size related or is there some other mechanism involved? Sandy King At 10:22 AM -0500 12/15/06, Gawain Weaver wrote: 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
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