Well I have now printed about 15 prints from the A3+ box. Absolutely no curling before, after printing or whilst sitting in the box. All prints completely flat.
I have done 4 prints at A2 size from a 17 inch roll - Epson P5000, canned Canson Profile, 2880 dpi unilateral, platen gap set to 3mm, suction to standard. And no real curling beyond what I experience with pretty much any other gloss paper - i.e. a very slight curl or more accurately not quite sitting completely flat. In fact the first print I did was about 5 hours ago, I laid it flat on a table and now it has just a slight touch of curl. No need to try and flatten it - it would take a mat without problems.
So I am very surprised at the comments here about curl. By comparison I bought some rolls of Hahnemuhle Photo Gloss Baryta which I had heard might be a replacement for the Harmon by Hahnemule Gloss which I really liked. Didn't really like the new paper and it had far, far more curl to it. So I think I am going to like the Canson, although it is early days yet and the 4 prints from the roll I made obviously came from the front of the roll. But from X2D files the colours are really good and the detail is exemplary. So far so good from my end.
