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How much white light is allowed?

ChristopherCoy

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As it turns out, I have a built in safelight in my darkroom. Doubling as a half bath/laundry room, I found I can use these 25w bulbs from centuries past that I found in my camera junk box.

However there is a little bit of white light at the base of the bulbs. Do you think this will affect paper from 3' away?



 
I'm sure they will affect the paper, but do a proper safe light test to verify.
 
It's a good question to which Rick has given a good answer. However in the U.K. you can get what looks like a dark brown/black plastic open fez-like cover that screws on to the bottom of the bayonet attachment and effectively covers the bottom of the bulb where the white light is.

I know you use Edison screw bulbs but there may be something that does the same job?

pentaxuser
 
red safelights were used way back when papers were graded and only sensitive to blue light. Today VC paper is senstive to blue and green over a much wider part of the spectrum. And papers are not all equal. You must test your safe light as Rick A says. And 3 feet is much too close anyway.
 
I'm with Rick on this, most likely won't work.

Aside from the band of white, 25 W is probably a bit too much. I tried a 25 W (white) in my filtered safelight and it fogged.
However, you could try wrapping the white part with some electrical tape, the bulb base will likely stay cool enough that it won't be a problem.
In any case, the only way to know is to do a proper test.
 
Take a bit of black paint and paint over the clear space above the base before you do any testing.
 
As mentioned, tape or paint will work fine. In addition, the wattage won't be as issue if you screw them into a lamp w/ a shade and address the opening at the top. Or, angle the light to the ceiling and bounce it back to your work area. It isn't the wattage, it's how much of it is getting to your area.
 
My safe light is 15 watts behind a dark red filter, slightly over one meter away from my work area. My tests show I can have paper open for nearly half an hour before any noticeable flashing.
 

Christopher, the red ones of these are the 635nm bulbs I use that I referred to earlier. Inexpensive and highly effective, these are an excellent choice. They are a favorite of the carnival companies to light their amusement rides super inexpensively, and so will be around for a good while.

I have six in-line in a homemade fixture that all sit underneath a half-cylinder "dome" of a single sheet of Rubylith. Naked they fail the CD/DVD test by showing tiny spikes of blue and green, and have subtly fogged paper that way in the past. However, under the Rubylith those spikes disappear completely and almost none of the red is blocked.

These are the guys I safely tested with Ilford MGIV FB/RC for at least 60 minutes pre-fogged. Don't know how long I could have continued as I terminated the test at that point. The DIY fixture clamps magnetically to the top of my Thomas Duplex. The six bulbs are 5+ feet from my easel, and illuminate that easel indirectly via a white ceiling tiles, as the Duplex housing itself blocks direct light.

The Duplex gets used for graded paper. These red LEDs for VC paper. (And Slavich graded, which specifies red only.)

I get zero fog and ridiculously long safe times...

Ken
 
I used red bulbs when I first started printing in the late '50s, but they were a really dark red, specifically sold as safelight bulbs. The ones in your picture look like decorative red bulbs that would NOT be safe.
 
wildbill said:
Why bother when you can get a suitable bulb for $4.29?
http://www.freestylephoto.biz/12622-Halco-11-Watt-S14-Red-Safelight-Bulb
I've had this bulb as my only safelight for about 10 years.
Click to expand...

I have a pile of those, retired since the LEDs mentioned above became available. For the same cost you can get a heck of a lot more light in your darkroom with the LEDs.

I do almost nothing but lith printing though, so seeing the development through a fog of brown liquid is critical (and that's an understatement)!

Here's the LED's spectrum overlaid on an Ilford RC sensitivity spectrum (the only paper spectrum I could find quickly when I made this graphic for the Facebook lith group). Pretty impressive.

 

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I agree with others and recommend a proper safelight test.a dab of red nail polish may cover your white spot on the bulb.
 
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