My dealings with Fred were always good and challenging. His workshop was the only one I ever needed to attend, way back in 1978. It was of college level and I believe you could get college credit if you applied for it. There I learned what a fine print really looked like and corrected all my mistakes. His images that he displayed were of great clarity and detail, rich and full of meat to chew. He also had a great collection of prints of other photographers. His Iceland Portfolio, which I bought, are a collection of very fine images.
There was one incident at the workshop, on a field trip, he did chase me away from an possible image that I was considering, very abstract of some boards and chicken wire. He said rather tersely, "There's nothing there!"
"The Zone VI Workshop" is an excellent book to learn the zone system from, simple and straight to the point. "The Fine Print" is an excellent reference for printing. I looked forward to his newsletters which were always inspirational, informative, challanging.
As for his products, I still use his exposure meter holster, print washer. He exchanged a camera bag 20 years after I bought it because of a bad zipper. Zone VI Brilliant graded paper, now discontinued, was rich and sharp.
I traveled to Vermont, a few years after attending his workshop and walked into the office, carrying a portfolio bag, to find him and Lil chatting and asked for a critique on the spot. He was very gracious and reviewed the work, labeling one as "a beaut." Lil took one look at the first print and said, "Oh, you have something to say!"
Well, now that Fred is gone, maybe some galleries will pick up on his work and sell it. After all the work of a dead artist is far more valuable then when he was living. Hmmm Picasso knew Fred Picker? I didn't know that.