Re: Lightsource for Gum

[Trevor Cunningham <tr_cunningham@yahoo.com>]

moving from egypt, where remarkably predictable sun and a lack of trees made sun exposures the best option...now, in jakarta, i have to compete with clouds and trees...however, the only ultraviolet tubes i've found are intended for use in bug zappers...are these suitable for exposure purposes?  if so, i'll begin investing in a gum kit

 

"somewhere between zero and one...everything else is exaggeration" - Anonymous

----- Original Message ----
From: Henry Rattle <henry.rattle@ntlworld.com>
To: alt-photo-process-l@usask.ca
Sent: Tuesday, August 12, 2008 5:03:30 AM
Subject: Re: Lightsource for Gum

Hi Bjorn,

I guess everyone does this differently – I take a minimalist approach, because I don’t work bigger than about 28x20 cm (A4 size negatives) which makes everything much simpler.

I use five 20-watt blacklight tubes. They are marked Sylvania Blacklight F20W/350 BL, and are about 60 cm long and 3.5 cm in diameter. Each is fitted to a separate single-tube holder, and these are mounted close together on a piece of board about 68x38 cm. Negatives are exposed at a distance of about 15 cm from the tubes, and I have never noticed any unevenness in exposure. Exposure times are around 5 minutes for gum and 10 minutes for cyanotype.

Anyone else?

Best wishes

Henry


On 11/8/08 17:39, "Bjørn Frostad" <myrvandrer@hotmail.com> wrote:

Hi everyone!
Thanks for all of your answers on this topic, and sorry for bringing it up once again....
...But just so I get it right from the begining:

-    Wich tubes avalible on the market today will give the the best results? - And is there any tubes that won't?
-    How many tubes will I need?
-    How far away from the print should the tubes be?

Thanks again

Bjørn