RE: BL vs BLB tubes for cyanotype

Chales, now that you say this, I'm pretty convinced that you did
everything right. Thinking over, I guess I found the why our exposure
times are so different. You were single coating right? I double coat.
When you double coat, exposure times are longer (because light sould
pass thru a thicker emulsion layer probably). I guess this is the main
reason of why there's so much difference between our exposure times.
Sorry, I should have figured this out earlier (blushing).

Thanks for your kind words.

Regards,
Loris.

-----Original Message-----
From: ryberg [mailto:cryberg@comcast.net]
Sent: 16 Kasım 2005 Çarşamba 19:28
To: alt-photo-process-l@sask.usask.ca
Subject: Re: BL vs BLB tubes for cyanotype

Loris,
     I have only 6 Stoufer strips so I make tests in sets of six times.
By overexposed I mean that two or more of the first steps are the same.
In his Precision Digital Negative system Nelson says to find the
exposure which just merges steps 1 and 2 and multiply by .7. I get to
the same place by finding the exposure which shows DMAX on step 1 with a
visibly lighter step 2. Using Nelson's method I would have had 4
minutes times .7 = 2.8 minutes. Using mine I get 3 minutes. My timer
won't resolve the difference but perhaps, now that I'm out of double
digit exposures I'll get a better one. Thanks for your interest. And
thanks for your regular contributions to the list--I always look forward
to them, even when they are about a process I don't use. Yours,
Charles Portland OR
Received on Thu Nov 17 05:08:01 2005