| 3.13.98 This brief article
appears in American Printer's "Ink and Paper" column. Preventing problems (and
waste) is a common objective of testing. This article identifies some of the common tests
for lithographic inks such as tack, stability, viscosity, yield value, water pick-up, and
fineness of grind which focus on physical characteristics. Other tests such as color,
strength, gloss, rub resistance, product resistance, and fade resistance focus on
performance characteristics. A number of newer testing methodologies are briefly reviewed
as they may address other important questions about ink properties and performance. For
example, it is important to know the dynamic surface tension of the fountain solution and
its affects on the resulting interface with ink. Another example is contact angle testing
which is used to measure the water resistance of images on aqueous plates. Images tend to
blend too easily if the water resistance is not sufficient. Other issues agddressed
include the affects of slow paper absorption of fountain soulution on ink transfer and
alternative approaches to water pick-up characteristics of ink.
Source: American Printer, November 1997, page 48.
Author: Terry Scarlett |
