I always tone my fiber prints as I like a neutral/cool look to my prints. In addition, "they" say that the prints are more archival if so processed - so I generally use the Ilford method of processing to increase the life span of the prints (although my early prints from 25+ years ago which were processed under less than optimal conditions still look fine). So I use Kodak Selenium toner at 1:30 for apx five minutes. Cools things down nicely and gives things a hint of an eggplant purple color.