Ron, my experience of cyanotype is that the paper is a major major
variable. Some will NOT do more than 6 or 7 steps without going into
reciprocity failure. If you can get hold of a sheet of Whatman Fine
Print, that's a VERY long scale cyanotype paper, and if that doesn't give
you 12 to 15 steps, there may be a problem with the sun up there in
Seattle. I don't remember if you said which Arches paper you were using,
but my list of "Short scale papers for cyanotype" includes Arches
heavyweight and arches 90 lb watercolor.
I'd also check to see if that paper is buffered, which would be a fly in
the ointment (to mix metaphors) & possibly the problem right there.
(Cyanotype likes slightly acid.) Then there's the fact that with a kit,
you don't know how the stuff is formulated or what the condition of the
chemicals are. And you could get a pound of fe am cit for that price, ya
know.... (tho of course that's been known to act up, too). However, if you
mix your own you can increase scale with more part B.
Another pretty good scale paper for cyanotype is plain old Strathmore
artists Bristol.... and I'd guess some of those la di da platinum papers.
In absolute extremis, try a flash -- if your prime exposure is an hour,
try bracketing around 3 minutes without a negative.... (Of course you need
more than one 21 step when your exposures are an hour long, otherwise
night up there near the arctic circle sets in before you've done your 2nd
test. In any event, having one 21-step is like having one sperm -- not
enough.)
Cheers,
Judy