Digital BW, The Print

<paul.roark@...> wrote:
>
>> ... the carbon images are the most lightfast....

Tyler wrote:

> That has not proven to be the case with some other inks.
> I'm concluding from this and other issues mentioned over the
> months that there are more manufacturing differences 
> between the brands than most of us realize.

That could well be.

I would also distinguish between "carbon" only and black only.  I was trying
to limit my statement to carbon.  Even the PKN that I've mixed is not pure
carbon and not the most lightfast.  Also, as another example, the Epson
"Archival" inkset black appeared to be a hybrid pigment-dye ink.  It tested
very similarly to the first generation Piezo and MIS blacks, which I believe
had about 8% black dye in them.  One of the problems with Wilhelm testing
is, I believe, that he tests at densities that will not pick up a hybrid
black ink's fading.  That's the only way the old Archival inkset did so
well.

Then again, an "enhanced" black comes to mind that must have had just under
30% dye in it so that, even though the black ink faded and changed color
horribly at first, it would not reach the 30% point at which Wilhelm
measures "display life."

Personally, I think Wilhelm tests are great, but I need to see what the
inkset looks like at about "20 Wilhelm years" of my own testing, at points
that include a 100% black.

I intend to test the Canon inks soon to see how they do.

As an aside, some of the "dye" inkset black inks have been part carbon for
quite a while. 

In addition to hybrid blacks, there is a possibility that the carbon has
been milled so finely that the particles don't have enough size to resist
oxidation for all that long.

Time and testing will tell.

Paul
www.PaulRoark.com