Some days back, I got involved in a discussion about contrast of pinhole negs. Maybe this turned me attentive to the topic, because recently I noted something peculiar of pinhole cameras with a curved film plane I wanted to share: here, in daylight situations, flare easily becomes a problem for me, and, in difference to other monochrome negatives, it is very easy to overexpose them, leading to dense negatives with severly reduced gradation. I learned this at my cost, because this effect becomes particularly noticeable, and really a problem for me, in snow situations. (I normally use 400 ASA film in pinhole cameras, equivalent to HP5, which I expose to 300 ASA)
The bright side: I can use my cameras with curved film in available light situations where a normal pinhole camera reaches its limits.