UV lighting for 20x20 inch cyanotype

[tom1]

Hello,

i work mostly in cyanotype in a studio. I made a UV bed of 10 stripe bulbs that can print 24x30 inch prints that i use on a regular basis, but have been asked to do a workshop in France, i'm based in the UK. For the workshop i need to process 20x20 inch cyanotypes, unfortunately my UV bed is too large to take to France.

Does anyone have suggestions of a suitable method to process 20x20 inch cyanotypes under 15 minutes and getting a consistent exposure across the print? I'm guessing i might have to go down the route of using bulbs but have not set anything like this up before.

Any help, input would be appreciated.

 

[Dan Pavel]

IMO you can use some bigger tanning lamp mounted on the wall at a distance from the paper so that it will illuminate evenly. You can find an used one at a reasonable price.

 

[koraks]

A tanning lamp will most likely not meet the 15 minute exposure criterion at the required distance.
Perhaps the old-fashioned way of a single metal-halide bulb with the appropriate ballast is the quickest solution, with the package (excluding the necessary shielding, which could in a pinch be improvised locally) being fairly portable. Something like a 1kW lamp should allow for manageable exposure times.

 

[Dan Pavel]

My tanning lamp is a 310 W Phillips tanning lamp with 8 tubes. The tubes are ~57cm long (~57X38cm is the active surface of the lamp) and, wall-mounted at ~ 50-60 cm from the paper surface, it gives me times of ~ 2-5 min with PT/PB, VDB and Gum while covering more than 20x20 inch.

 

[koraks]

At that power level, it will work, yes. I was thinking of the small 15-20W face tanning solutions; those won't cut it.

 

[cliveh]

We are moving into the summer months. Why not use daylight which is rich in UV, especially in the morning. 30 minutes on a sunny day should do nicely.

 

[koraks]

Repeatability.

 

[tom1]

My tanning lamp is a 310 W Phillips tanning lamp with 8 tubes. The tubes are ~57cm long (~57X38cm is the active surface of the lamp) and, wall-mounted at ~ 50-60 cm from the paper surface, it gives me times of ~ 2-5 min with PT/PB, VDB and Gum while covering more than 20x20 inch.

do you have a link to it, i could only find products for face tanning, or full body, nothing in between. A UV tanning lamp that's transportable sounds ideal.

Has anyone used the Osram ultra vitalux 240v 300w-e27: https://www.lamps-on-line.com/osram...MI69KWq9zZ4QIVwrztCh0JtgvNEAQYBCABEgKhXPD_BwE

Would it be powerful enough and would it be able to achieve the coverage i'm after?

 

[Dan Pavel]

Mine looks like this:

The digital timer is mounted by me.

I couldn't find the exact model but this lamp from ebay looks quite similar (8x60 cm long tubes):
https://www.ebay.co.uk/itm/Phillips...m3d8884aee5:g:~iMAAOSwbS1cs3S4&frcectupt=true

The timer I have used is this model:
https://www.ebay.com/itm/Timer-12V-time-switch-24V-work-time-counter-with-alarm-buzzer-time-delay-relay/192081552860?ssPageName=STRK:MEBIDX:IT&var=491972549940&_trksid=p2060353.m1438.l2649