Black Light Bulbs

ced · Dec 17, 2013

Excuse if already posted. Would these bulbs be good for Gum Printing as they are for Cyanotypes please?
(http://www.velleman.eu/products/view/?id=381476)
They are already installed at home and make excellent Cyano's but I want to make Gum's too.

Uncle Goose · Dec 17, 2013

If they do Cyano's then they will do gum's too.

ced · Dec 18, 2013

U.G. Thanks for responding and what do you think the difference in exposure time if you have experience with this method?

Loris Medici · Dec 18, 2013

Ced, that highly depends on the pigment / dichromate / gum content and coating thickness of your emulsion. For my usual working procedures, gum was around 2 stops faster than trad. cyanotype. But this is absolutely non applicable to your working conditions / style. You'll have to test it for yourself.

Regards,
Loris.

ced · Dec 19, 2013

L.M. Thanks for this info it might just be a pointer!

AgX · Dec 24, 2018

ced said:
Excuse if already posted. Would these bulbs be good ...

These are no "bulbs". But they are fluorescent tubes, which basically only emit UV light.
(That in household tubes is transferred by the inner coating into visible light.)

In contrast the classic "black-light bulb" is an (maybe overrated) incandescant household lamp with an filtering coating that only transmits the UV/far-blue part of its edmission, wich is very weak though.

ced · Dec 24, 2018

Duh...

AgX · Dec 24, 2018

I never came across the lamp you linked to, but often the "black" incandescent ones. So when reading black.light bulbs I immediately think of these incandescant ones.

Black Light Bulbs

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