Need info about using De Vere 507 cold cathodegreenspun.com : LUSENET : Large format photography : One Thread
Hi, As a newcomer to cold-light heads I need some help re: variable printing times. Although I let the enlarger warm-up for 20 mins or so before printing it is very rare that I can get two succesive prints to match. I asked a guy in the shop where I bought the enlarger what he thought about using a voltage stabliser, but he told me to forget it and just keep switching the enlarger on and off. He also said to forget about exposure times of less than 30 secs. Is this right? I paid a lot for an RH Designs Analyser Pro Timer partly because of its test-strip feature, but my printing times are now so long that I cant use its 7-step range.
Also, with this timer you cant leave the enlarger on for any length of time to warm it up - it cuts out after a short while. This means pulling the lead to the light head out and plugging it in elsewhere, which is inconvenient.
What I basically would like to know is whether this is a common feature of cold light heads, or whether my one is faulty/eccentric/past-it.
Thanks for any help.
-- Neil Miller (email@example.com), February 15, 2002
Neil, I have an ancient Devere 101 (full plate) with a cold cathode head, I generally switch the beast on and leave it on using the swing across red filter for exposure ( tested this for fog and their was nothing appreciable). It does seem a bit variable for the first few minutes, then seems to be fairly consistent though I have not done any analytical tests, perhaps all that on and off is upsetting it! My record for an exposure at F11 is 2 mins, this is for a shot of white sands in the states where I deliberately put the sand at zone 1, I expect exposures of 30 sec to 1 minute as standard; like taking the pictures in the first place, it is a slow stately process and you have to wait for the light.
-- Charlie Skelton (firstname.lastname@example.org), February 18, 2002.
Charlie - thanks for replying. I have adopted this procedure and, although slow (or "stately" as you call it) it solves the problem.
I wish I hadn't spent so much on a fancy timer though - could have spent the cash on more film/paper!
BTW, I live nr Southend.
-- Neil Miller (email@example.com), February 21, 2002.