Topic: Red light question

[choppert]

No, not a query on kerb crawling!

I've a downstairs loo which I use for loading films onto spirals.

I want to make some simple contact prints so need a lighting solution to enable me to dunk my paper into the dev.

1  Should I buy a red bulb for the existing light socket, or try and fashion a plastic cover over the existing bulb?  If so, what would you recommend?  Did I read that a green bulb can be used?
2  What's the best source of light for contact sheets? (given I won't be buying an enlarger)  Will a normal bulb work?  Should I use a flash gun? 

Please feel free to assist 

Chops

[Francois]

Well, for the safelight I'd go for the real thing since I wouldn't want to risk fogging the paper. The green light won't work as it is used in some enlargers instead of the Magenta (cold lights come to mind).

A good used Paterson safelight can be had for cheap and they work wonders. Just plug in and that's it.

As for doing the contact prints, any light will work. You probably would want to go for a 40 watt appliance bulb on a wire. Once you got the height and timing figured out, you can mark the wire with a reference point so you can go back to it quickly.

Also, this is the perfect condition to try out single tray processing. All you need is a funnel to put the chemicals back in their bottle each time. It also keeps the smell down.

[choppert]

Oooops, forgot to mention - no power in the loo!

So the ceiling light is going to be at the centre of this

[Pete_R]

When I had a darkroom, I removed the centre room light and replaced it with a piece of wood on which was mounted,and suitably wired, a proper red safe-light, a changeover pull switch and a standard lamp holder with a normal bulb fitted. The light gets turned on/off by the normal switch and the changeover is used to switch from red to normal light. I used that setup for years. Sounds like you need something similar. How are you with electrics?

[choppert]

How are you with electrics?

I'd be fairly calamitous with the piece of wood, let alone anything clever!  Think Homer Simpson!

How about a torch with some Quality Street wrappers on?   

[Heather]

I use a really long extension cord to run a safelight into my bathroom.
Green is only used with colour materials and only indirectly and it's an extremely *dim* green. "Amber" and Red are the two used in B&W paper photo stuff.
I have just used the overhead light for photograms in the past but you can use something more handheld if you wish. Should work pretty rapidly and possibly not too bright so I don't think a flash gun would work so well (though I have used that for sabbatier effect)

[Heather]

oh and this may be helpful http://www.rhdesigns.co.uk/darkroom/html/safetorch.html

[Francois]

You could also use one of these gizmos... They probably have something similar in the UK for the British G type plugs.

[sapata]

How are you with electrics?

How about a torch with some Quality Street wrappers on?   

Exactly what I use:P  I have no choice but to wrap a deep red cellophane in a small torch...

[Pete_R]

How are you with electrics?

I'd be fairly calamitous with the piece of wood, let alone anything clever!  Think Homer Simpson!

You can do it. Look, here's a link to a circuit diagram (you can omit the 666 timer as you only need that for colour). OK?

http://xkcd.com/730/

[Jack Johnson]

Should I buy a red bulb for the existing light socket, or try and fashion a plastic cover over the existing bulb? 

I read somewhere recently (likely Flickr) about some person looking for a safelight and someone at his local camera store found out that the red LED Christmas lights worked, had tried it and said it worked, so the poster tried it and it worked, so now I'm going to give it a go.

Found another reference to it here: http://www.largeformatphotography.info/forum/archive/index.php/t-71294.html so I'm hoping it's not all lunacy.

[Francois]

It's quite possible that it works. Durst used to make LED safelights (including a small battery operated model).
Thing is LED's don't work like a lightbulb. They have no filament and at their core produce only a single wavelength compared to the bulb. They use a very weird physics principle (the guy who invented them also won a Nobel if I remember)... electrons pass through a sieve emitting light in the process.

Anyways, best way to test them is to do the penny test on a scrap of paper.

[Heather]

The weirdness of LEDs is one of the good things about them for darkrooms. If you can get the wavelength data for the LEDs you can match it up to the sensitivity curve for your paper. Because LEDs tend to be a very narrow little peak on the graph, it'll probably be *more* safe than a filtered safe light because it won't range up or down depending on age or useage. I think because of the narrow peak you can also have it visually more bright than a dim 10watt bulb.

I've not used them at all though, it's just what I've heard/read/looked at.

[Francois]

You're probably right about this Heather.

For those who are geeky enough to want to know the fascinating details that are at work in this tiny common piece of electronics, here's the full wiki page http://en.wikipedia.org/wiki/Led

[Dave Elden]

The red LED lamps are a good option for safelight - but test to verify they are safe with your installation & materials.  The advantage they have is they are brighter than filtered incandescents can safely be, they run cooler using less power and will go many times longer before needing replacement.
Someone else said "If you can get the wavelength data for the LEDs you can match it up to the sensitivity curve for your paper." True but I would suggest just doing a test. Intensity is a factor, even an LED which looks OK on paper can cause fogging if it is bright enough (and yes, I'm geeky enough to have actually measured an LED output spectrum and compared it to the paper sensitivity curve, details here http://www.apug.org/forums/forum43/84002-led-rope-light-possible-darkroom-applicaton-3.html )