Mini-Encyclopedia of Papermaking Wet-End
Part Three: Equipment & Unit Operations
Papermakers use the word "graniting" to refer to a speckled appearance of paper, especially in cases where dyes have been added. Graniting may be caused when high-affinity dyes are allowed to contact furnish or white water at relatively high concentration or with inadequate mixing. The solids at the point of dye addition become irreversibly stained and remain deeper in shade than the rest of the furnish. Graniting usually can be reduced by dilution of the dye with solids-free water before it is added to the furnish. Also it is recommended to add high-affinity dyes to points in the process where there is good mixing. Graniting may also occur if dyes are allowed to contact oppositely charged materials before they have become well mixed with the furnish.
Request from the webmaster: Our goals include brevity and accuracy. Hopefully we have succeeded with the first goal without sacrificing the second. Please let us know right away if you find an error or omition. Also, please indicate points that need a clearer description.
RETURN TO INDEX PAGE OF ENCYCLOPEDIA
This page is maintained by Martin hubbe, Associate Professor of Wood and Paper Science, NC State University, email@example.com .