Measuring the Summer Effect Around the World, 2003 Fall Technical Conference
Since 1998 the “summer effect” has been investigated under lab conditions and measured at an industrial
scale in six different benchmarking studies covering North America, Europe, and the Asia-Pacific region.
The “summer effect” is a period during the summer months when mills experience a loss in brightness due
to accelerated aging of the ink. The extent to which a newsprint deinking operation loses brightness is a
function of ambient temperature, furnish, type of ink carrier, pulping energy, and mill design. The
significance of these independent variables were investigated based on the collected industry data. The
results show a commonality with increased ink fragmentation and redeposition with significant differences
in bound ink, magnitude of the effect, and approaches to handling the problem.
Measuring the Summer Effect Around the World, 2003 Fall Technical Conference