Brightness can be achieved in many ways. The easiest and most expensive way is for a mill to "buy" it in the form of higher quality and cost furnish. Another “quiet” cost is by deinking aggressively which hurts mill yield. Still another is to add bleach or brighteners, however, these methods have limitations.
One of the most cost-effective means to increase brightness is to deink better. Though sub visible ink cannot be seen as specs, it is this ink size range that makes a deinked pulp dark.
Many times the inks are never detached from the fibers. Other times they smear along the fibers and darken the entire stock. One of the most common such events occurs in dispergers where significant percent reductions in visible ink simply push inks into the smaller size ranges that appear dark.
EDT’s Enzynk® treatments maximize ink detachment such that all plant equipment can do a better job in removal and issues such as brightness “reversion” in dispersion are minimized. Brightness gains of 2-4 points are commonplace among EDT customers. As with dirt reduction, quality improvements in brightness enable mills to increase production and shift to lower cost wastepaper furnishes.