Sometimes a customer will ask for a PMS color match.  PMS stands for
Pantone® Matching System.  Actually, there are a number of color arrangements
described by the Pantone Company.  So you want to verify the color the
customer wants is from the screen printing colors defined by Pantone.  Pantone
is an independent company that receives samples from the various ink manufacturers
and determines what the color is when compared to a color guide approved by
the Pantone Company.

The leading ink manufacturers offer formulation books that are recipes of ingredients to
produce each PMS color.  To produce such colors, a gram scale and wide
selection of ingredients will be necessary.  Customers typically do not
want to pay for the time of mixing inks and then matching that product to a
sample provided by the customer.  Sometimes mixing by a formula does not
match the color the customer thinks he or she is ordering, and some adjustments
are necessary.  That all takes time.

The ink manufacturers offer a wide variety of colors, and the screen printer’s
life is easier when customers are only allowed to see color chips of pre-mixed
inks.  If a PMS color match is requested, a substantial charge should
be added to the price of the job. 

You may chose to mix your own colors like a landscape artist plays with colors on a
palette. Inks from different manufacturers can be added together.