UV Light Box Died

[Jim Noel]

Try the simplest solutio first.
SOmetimes for an unknown reason my grounding doesn't cause the bulbs to ignite. I just reach in and run the back of my hand over the tubes and they light.
It is worth a try.
Jim

[Michael Mutmansky]

If you have any real evidence that shows an increase of separation of the high values with high vacuum pressure I would be very interested in seeing it. My experience is that more than 5-10 inches of mercury is plenty, and that more pressure can be detrimental in some cases. However, I am open to modify my thinking on this if there is evidence to the contrary.

Sandy

That is my feeling as well. I've seen a vacuum frame squeeze liquid out of the fibers of an otherwise dry piece of paper and ruin a negative, so I am wary of using any more pressure than is necessary to obtain good contact.

I don't adopt a procedure unless it has proven performance benefits, so I'll try a comparison, but I am somewhat skeptical that it will improve the highlight detail with my printing conditions.


---Michael

[sanking]

I don't adopt a procedure unless it has proven performance benefits, so I'll try a comparison, but I am somewhat skeptical that it will improve the highlight detail with my printing conditions.


---Michael

I would have to add that even if highlight detail is improved by increased pressure it is something of a moot point with me since using over 20 inches of mercury is really not an option with inkjet negatives on the substrates I use, Pictorico and Clearprint. That much pressure would simply pull the ink off the substrate during exposure and fix it to the sensitized material, both with Pt./Pd. and with carbon. And even if one were to use a piece of mylar between the negative and sensitized material the pressure would suck moisture out of the material and adhere it to the mylar. I have experienced both of these things even with pressure at between 15-20 inches of mercury.

Sandy

[donbga]

Yes, I do pull it to 25" of Hg. There is anecdotal evidence to suggest higher vacuum increases separation of the high values. PM me if you would like to discuss this obscure observation in more detail.

Why not discuss this publically? I'm very curious. I'm not disputing what you suggest, I'd just like to learn more.

[juanito]

I use 21 inches of pressure. I use pictorico for pt/pd and I haven't had any problems such as you describe. The ink side of my negatives are in direct contact with the emulsion.

[sanking]

I use 21 inches of pressure. I use pictorico for pt/pd and I haven't had any problems such as you describe. The ink side of my negatives are in direct contact with the emulsion.

Are you working in Mexico City? If so your climate is very dry. The problem is one that happens when the sensitized material is wet or humid, either naturally in conditions of high humidity, or from humidifying to increase Dmax as some people do with Pt./Pd.


Sandy

[juanito]

Yes, I'm working in Mexico city and humidity is not a problem here. It's good to know what can happen when working in high humidity environement.
Thank you

[Joe Lipka]

I bow to the collective wisdom that is APUG. After confirming that there were no fuses of any type in the UV light box, I unbundled all the black wires, straightened them out and then re-twisted them into a nice bunch. I did the same for the white wires. SAFETY NOTE: I then plugged in the unit and all the bulbs lit up. Thanks for the assistance APUG. You have saved the Alt process print exchange.

[Bob F.]

Sounds like a loose connection then Joe - check all the terminal screws holding those wires in place.

Cheers, Bob.

[BrianShaw]

SOmetimes for an unknown reason my grounding doesn't cause the bulbs to ignite. I just reach in and run the back of my hand over the tubes and they light.

Is this a miracle or the gift of healing? Have you tried running the back of your hand over a sick person?