Need info about using De Vere 507 cold cathode

[Neil Miller]

Hi, As a newcomer to cold-light heads I need some help re: variable printing tim es. 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 s hop 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. H e 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-s trip feature, but my printing times are now so long that I cant use its 7-step r ange.

Also, with this timer you cant leave the enlarger on for any length of time to w arm 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

[Charlie Skelton]

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

[Neil Miller]

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.