In 2005 I attended a workshop with John Sexton where we compared prints made by the participants from identical negatives.
A few months before the workshop, John sent us each an identical negative, with instructions to make an 8x10 print as best we could and put our name on the back.
Upon arrival at the workshop, we handed them to John and were not allowed to see each other's prints just yet.
By the end of the two week workshop, we were all pretty familiar with each other's work. Each of us had had our portfolios reviewed by the entire group, and we had done a lot of work together.
On the final day, the assignment prints were lined up on the wall. To keep it interesting, John included versions made by his wife Anne and the assistant. There was a significant variety of interpretations of the same negative,
We then had to guess which participant made which print. It was a lot of fun and very informative. The more accomplished printers had an immediately recognizable style of printing.