Archived from groups: comp.periphs.printers (
More info?)
I believe there are some error in that article sited.
Metamorism is, in the most simple form, when two samples of a color look
the same under one lighting but different in another. For example, you
take two samples of black fabric to make a suit. In the factory the two
colors look like the same black color, and your pattern cutter cuts the
fabric and makes a suit from two bolts of fabric. The suit is ut
together and it looks greet in the factory, under the factory lighting.
Then the suits go to Bloomingdales or Sears, or whatever, and the buyer
is shocked. Randomly, in their offices the left lapel is a neutral gray
black, but the right lapel looks purple-black.
That is metamerism.
In inkjet printers, it is VERY rare to fine it in dye inks. It is
mainly a pigment colorant issue, and you will notice in the article you
sited, the printers, the 2000P and the 7500 are both durabrite ink
(pigment colorant).
The problem in the Durabrite inks was mainly the yellow ink, which
tended to go "greenish in some lighting conditions, while showing a
normal yellow in others.
It seems to have something to do with the pigment particles and how they
reflect the different light frequencies back. Epson's first repair was
to change the dot pattern, which did help. However, ultimately they
changes the yellow pigment formulation.
The newer Ultra chrome color inks show very minimal metamorism, again
the yellow was the problem, and they had to go with a less stable
pigment to accomlish that, but it lowered the age permanence of the ink set.
Again, you need to try to identify in which areas of the print, the
problem occurs, which lighting, which ink density,. is the whole page
involved or only printed area, etc.
Again, I have not seen metamorism in dye inks, but perhaps something new
will come of this.
Art