Re: BL light box 'blues'
On Mon, 30 Mar 2009, Ken Sinclair wrote:
Have recently decided to intensify my interest in non-silver, I constructed myKen, for what it's worth I note that my time for cyanotype is circa 8 minutes...but I've got the bulbs stacked as tightly together as possible (that is, with the fixtures touching) which measures 1-1/2 inches bulb edge to edge, and the distance from the bulbs to the carrying glass (which in my setup is over, not under), is slightly less than 2 3/4 inch. I also put shiny white foam core all around the sides to reflect light *in* to avoid light fall-off around the edges, which it pretty much did.
I don't recall the developer, but those are pretty contrasty negs, printing (from memory, forgive me if I'm wrong) circa 10 steps on the 21-step.
However I recall getting an e-mail from a former student who was frantic because she was about to teach a class in cyanotype & her new set-up was clocking 25 minutes... We back-and-forthed on it for about a week, until the light dawned: It seems when she ordered the glass they asked did she want anti-glare (or some such) and she said yes, which it occurred to someone or other cut down the light.
Meanwhile and in any event... you mean you don't have a 21-step? Or access to a densitometer? Tsk tsk...!!! But if you mail me a neg (you're in the US, no?) I'll measure it for you. Sorry, I've run through my supply of 21-steps (I used to get 100 at a time for classes, & send subscribers small refunds in 21 steps), but I assume Stouffer is still in business and findable on the web... And whether you do pyrocat or hang-the-cat, trust me, the 21-step -- preferably at least 10, because you can do 10 "tests" (variables) at a time, is a crucial tool.
But, whatever you do, NOT BLB bulbs. They're at least 20% slower, and not as well formed a tone.
Meanwhile -- enjoy !