dumb one, reason I cant use an enlarger

[bspeed]

hoke-dok.. any or (what is) the reason that an Enalrger cannot be used to print the Albumen-Silver Nitrate prints ?

 

[David William White]

Speed of emulsion is WAY too slow. You'd need to leave the enlarger on for...like...a week.

 

[fschifano]

Because the emulsion is sensitive primarily to UV light, something that a conventional enlarger with a tungsten or even a cold cathode lamp does not produce in sufficient quantities.

 

[David William White]

^ better answer

 

[23mjm]

What if you rig a UV light source into an enlarger???? Would that work.

Danger this posting was just out of curiosity!!!

 

[David William White]

Lots of threads on UV boxes, as these alt processes are generally contact prints. I don't know if you could get enough UV illumination into such a small place without frying your negative in the process. Contact prints seems to be the way to go, and it seems so much easier to use the enlarger to make an enlarged negative for contact printing, either on traditional film, on ortho/litho film, or even on paper negatives (a la Fox-Talbot).

UV boxes still require long exposures, 20 minutes, one hour, etc., but they do give you consistency from session to session from the same contact negative. However, backyard sunlight is still much faster, way cheaper, more fun, and is the traditional way these things were done.

 

[23mjm]

Thank you for the answer---it was just curiosity--I can't ever find time to do traditional darkroom stuff now--let alone try something new.

 

[tim_walls]

What if you rig a UV light source into an enlarger???? Would that work.

Danger this posting was just out of curiosity!!!

Off the top of my head, I think you'd struggle with focusing - the thought has crossed my mind before now as well, though! Making internegs/enlarged negatives for contact printing alternative processes is very much on my to-do list, but being able to use the enlarger directly would be rather convenient

(I'm assuming that focusing with a regular bulb and then switching in a UV bulb and keeping the focus the same wouldn't work because the focus at UV wavelengths will be different from visible, but I've no idea if that assumption is true...)

 

[bspeed]

LOL, only a week eh!!
Ok, I thought it was indeed realted to UV, I should read up on how regualr enlarging paper differs. I have access to a UV box at school, and of course to the Sun (If I behave myself). hehe.

Thanks for the replies to my dumb question!!

 

[fschifano]

Off the top of my head, I think you'd struggle with focusing - the thought has crossed my mind before now as well, though! Making internegs/enlarged negatives for contact printing alternative processes is very much on my to-do list, but being able to use the enlarger directly would be rather convenient

(I'm assuming that focusing with a regular bulb and then switching in a UV bulb and keeping the focus the same wouldn't work because the focus at UV wavelengths will be different from visible, but I've no idea if that assumption is true...)

Not only the focus problem. The enlarging lens itself would block most of the UV radiation even if you could manage to generate enough of it up top. Greater minds than ours have thought this out many times over, I'm sure. If there were a way to do it, I suspect that we old timers would have heard about it.

As an aside, there are specialty taking lenses designed especially for UV photography. They are very rare, and very expensive, and require "substantial" amounts of UV radiation. See this link and this for information on the UV Nikkor 105.