Low wattage safelight for polycontrast?????

[Calamity Jane]

My old darkroom was a small area (not much more than 8x10) with a high ceiling (9 feet) and I used a single BrightLab "Jr" bulb (11 Watts, red) - it seemed good - nice subdued light, no fog, safe for polycontrast paper and just about anything else.

My new darkroom is large (12x16) but the ceiling is LOW (6' 6") irregular (where it dips under beams, pipes, etc.) and black (a sheet of black builder's plastic so I don't get any dust from the floor and joists above). I put standard lamp bases in 4 different work locations for safelights (wet side, dry side, one over the Jobo, and one by the enlarger) since the low ceiling doesn't lend itself to a single lamp.

With the low ceiling, I am finding the 11 Watt BrightLab Junior awfully bright! I don't feel inclined to install 4 of them to spread out the illumination.

Is there a lower wattage bulb that is safe for polycontrast paper???

(Maybe I'll have to wire the Juniors in series to drop the light level????)

Thanks!

 

[David Brown]

In a former darkroom, I had two of the big Brightlabs. I don't remember the wattage, but they were the ones about 6 inches in diameter. It was bright, but tested safe.

Bottom line is you have to test, as with any safelight. Maybe one solution would be to switch each one separately. However, with the black, you may find that they are OK.

Good luck.

David

 

[kenh]

I had a lot of trouble getting my safe lights setup. I used red LED lights and had difficulty getting the light bright enough for me to work (even in a room that was painted white). I increased my LED count to over 400 LED's (it took multiple power supplies to generate the sort of power necessary). Still, it was not bright enough, but it fogged paper pretty easily - within 2 minuits. Finally I switched to amber LED's toned them down so I only have 8 on at any given time, reduced my power supply to only one unit and bang, I could see easily, and my paper did not fog for over 10 minuits!

I guess my point here is that no matter what you have to test your safelight to see if it is truly safe, and you have to adjust them by moving them, reflecting them off walls or white cards etc. to get to the point where you can work.

One last comment, my safe lights bounce off the walls (I would have put up some white cardboard if the walls were not white). The bounced light is far better than direct light because it gives a more uniform illumination to the room (i.e. not hot spots), and more importantly the shadows are soft enough that I can open a drawer and see into the drawer, or open a cabnet and see inside the cabnet.

One last comment, I used a light meter to measure my safe light's relative intensity. That is, I setup to test the safelight, fogged the paper after 1 minuite then after measuring the intensity I adjusted the lights position to give me about 4 stops less light, this made testing the safe light take far less time.

Good luck, remember to test, and adjust.

 

[Calamity Jane]

Thanks for the suggestions.

The LED lamps look interesting but considering I need 4 of them at $30 each I decided to go with the BrightLab Juniors ($9 each) and wire them in series in groups of 2 (the way I have wired the room makes this easy to do). If that's still too bright, I'll stick a diode in series which will drop the light to about 40% or switch to 4 lamps in series.

Thanks again!

 

[glbeas]

Put them on a dimmer control Jane!

 

[Calamity Jane]

D'OH!

A dimmer - OF COURSE!

Too many years in engineering - blew right past the simple and obvious!

 

[MikeS]

With the low ceiling, I am finding the 11 Watt BrightLab Junior awfully bright! I don't feel inclined to install 4 of them to spread out the illumination.

Nothing wrong with having a bright darkroom, as long as it's a light that the paper is blind to that is! I would put the 4 of them in, and do a test to see how the paper likes it (or not).

I really like the Brightlab Jr. bulbs, and I have 2 of them in my darkroom, one by the enlarger, and one by my work surface (the top of my clothes dryer) where I do all sorts of stuff, from loading LF film holders (without the safelights on, unless it's ortho film), to developing paper. Just 2 Brightlab Jr bulbs was what I thought was just right, not too light, not too dark. I recently got an Aristo 18" amber safelight and was AMAZED at how bright it was! With my previous 2 Jr bulbs I could barely see, but could see well enough, after all it IS a DARKroom I was in, so I didn't expect much brightness! As my ceiling is fairly low I mounted it upside down so the safelight is shining toward the ceiling, and this really lights up the whole room! I can read a book in the darkroom now!

Like everything in life, nothing is free. With my old setup of just the 2 Brightlab Jr. bulbs there is absolutely no fogging of paper, even after 15 minutes of exposure to the safelight (I usually do a test with 5/10/15 minutes of exposure), with the Aristo safelight, a sheet of paper directly under it (on the dryer), and another on the enlarger's baseboard, the one on the dryer shows a slight fog at the 10 minute mark, and slightly more at the 15 minute mark, while the one on the enlarger shows only very faint fogging at the 15 minute mark. In actual use I've not seen any evidence of fogging of any paper I've used, other than some old Polymax that was just bad, not fogged by safelight.

-Mike

 

[PeterB]

I am using cheap 50 cent led's in series with an old wall wart and resistors. I had to use almost 500 watts of resistance to get them dim enough! Forget those $30 LED's. Don't need them.

outofoptions,
what colour LEDs did you use? Have you done a paper fog test with the paper you are using?

Also sorry to be pedantic in correcting you, but units of resistance are measured in ohms not watts. If you meant to say that you dissipate 500 Watts of power across/from your resistors, then you have built yourself a rather hefty heater for your darkroom! Doesn't it heat things up pretty fast? Anyway, I'm not sure I understand why you needed to dissipate so much power.

regards
Peter

 

[Calamity Jane]

WAHOO!

Installed dimmers on the safelight and "low light" circuits - that's just the cat's meow! Can set whatever light level I want.

Chased down the last of the tiny light leaks in my new darkroom (and fixed them) - was sure nice being able to dim the lights to almost nothing instead of stumbling around in the picth black. (And with the last of the light leaks fixed, it IS pitch black!)

Dimmers - brilliant idea!

 

[kenh]

Sounds like the dimmers was the answer. Fantastic.

I just wanted to clarify what I used. I used the amber LED's from a automotive store that is designed to be used as the side markers on a trailer or other vehicle. This cost me about $10. Then I powered it with a 9 volt brick supply that use to power up my cordless phone (that died). Thus the system only cost me about $10 and only took about 15 minuets to put together.

One last comment about safe lights. Check each paper you use. I found that one manufacture (Ilford) could stand a lot more light than another (Agfa). So just because your safe light is Ok with todays paper selection, make sure that you re-check it when you add a new paper into your darkroom.