led safelight - superbrightleds.com?

MurrayMinchin · Jan 7, 2007

Hi there,

Could you please check out the third light down on this webpage...

Dead Link Removed

...(model PAR20-x36, 595nm amber) and let me know if you think it could be used as a safelight?

I'll be building an 8'x13' darkroom where (for the forseeable future) I'll be using Multigrade IV fb paper. This light has a 25 degree beam pattern which I guess I'll bounce off the ceiling and/or wall for even light. I have a Thomas Duplex Super Safelight (sodium vapour) right now that's heavily draped in all manner of cardboard and black paper to make it safe for VC paper in my existing, way too small darkroom. I plan to get an enlarging meter for the new darkroom which requires the safelight being off when the enlarger light is on, so the old safelight will have to be retired.

Is this do-able????

Murray

menglert · Jan 7, 2007

I use similar LED bulbs in my darkroom, but I'm sorry I don't remember the specific nm... I know it was 5xxnm. Although I did choose to use the red bulbs.

Anyway, I was very happy with them, and never had a problem, even with papers like Fotokemika.

You could check the paper company websites and see if they give a safe working spectrum.

Regards,
Martin

Justin Low · Jan 7, 2007

I use red LEDs now, and find them acceptable. No fogging at ten minutes. I intend to try the orange ones soon as they are brighter.

Fotohuis · Jan 7, 2007

The bandwidth of the LED's are important then. So in most cases you need selected types with a small bandwith (30-40nm) and that will drive up the price. (e.g. Jobo LED darkroom light).
A sodium vapor lamp is 590nm +/- 6nm which is VERY small and also suitable for RA-4 papers.
Disadvantage is the price of the bulb, limited lifetime and that you need a mechanical aperture to dimm these kind of light sources.

Best regards,

Robert

Lee L · Jan 7, 2007

Murray,

I'm using superbrightleds light bars and their Edison based Model E27-W24 Wide Angle and E27-W8-G with the same wavelengths (595 and 635) as your chosen option. I use the red and amber LEDs with Ilford MG papers with no fogging problem. You might find the smaller 24 LED bulb, or even the 8 LED E27-W8-G LED bulb sufficient.

I used to work in a very large darkroom (20 x 24 ft) with high dark ceilings with a single Thomas unit and found that the wings-open setting fogged Polycontrast Rapid pretty quickly.

I put the Edison based wider angle superbrightled bulbs in an inexpensive spun aluminum reflector clamp-lamp from the hardware store and bounce them off the 8 ft light colored ceiling. BTW, the circuitry in the superbrightleds will only allow a little (and almost single step) dimming with typical AC rheostats, not a full range.

Lee

MurrayMinchin · Jan 7, 2007

Thanks everyone for the input.

Lee, congratulations on post # 1,000!!!

I was considering the wider angle unit too. They estimate it would be as bright as a 15 to 20 watt incandescent, which would make it brighter than a 'normal' safelight which uses a 15 watt bulb behind a filter. They're so cheap, maybe I'll order one of each.

Thanks again,

Murray

Troy Hamon · Jan 7, 2007

Hi Murray,

I haven't tried amber, but I have six of the E-27 W24 bulbs in red. One of them serves as my porch light basically letting people know that we're in the dark inside...not just an average porch light, the red always makes people stop and think (though sometimes not about photography...). Then, inside, I have two set up in light fixtures directed at my kids play table. And finally, also inside, I have one mounted in a bare-bulb socket over each bench. That puts them about four feet from the bench. I did fogging tests and couldn't find any fog at all, and when all the lights are on it's pretty bright, for a darkroom under safelight anyway.

Congratulations on the building project...is this a room in your house or are you as crazy as me?

Troy

MurrayMinchin · Jan 7, 2007

Hi Troy..hmmm...with that red porch light a person could actually make some real money in a darkroom

We have a fully insulated (built from rough cut 2x6) 26'x13' garage that is adjoined to our house, and it's going to be mine, ALL MINE!!!! So far the darkroom portion is going to be 13'x10', but that will probably change more than a few times before construction begins...

I'm going to take your idea and make a dedicated play area for our daughter. That's a stroke of genious! There's also going to be a revolving darkroom door between the drymounting/framing/print storage/gallery area and the darkroom, so there's never a locked door between me and my family.

I'll be trolling APUG's depth of knowledge a lot in the next few months!

Murray

PeterB · Jan 12, 2007

MurrayMinchin said:
Hi there,

Could you please check out the third light down on this webpage...

Dead Link Removed

...(model PAR20-x36, 595nm amber) and let me know if you think it could be used as a safelight?......<snip>........Is this do-able???? Murray

Hi Murray,

unfortunately I won't be able to give you a straight yes or no, in fact ultimately you will need to try out the light and report back to us.

I would appreciate knowing what you find out with the safelight fogging tests you perform.

After I did extensive research into an appropriate wavelength and bandwidth, I settled on 605nm "Amber" LEDs - just 10nm above what you are getting. They have a very narrow FWHM. i.e. their spectral half width is 17nm (@20mA). I found them a real pain to obtain in "sample" quantities (like <2000 !!). Ultimately an Agilent sales rep got sick of my persistence and gave me some "samples" !

The musings of others I collated on the topic can be found here. I would highly recommend reading that document.

Perhaps you could email the manufacturer and request they supply you with the manufacturer of the LED so you can check out its datasheet. In my experience the chinese owned LEDs had unacceptably large spectral half widths (which is not a good property), so I hope you have good quality LEDs.

When I end up testing mine out (not for a while yet I'm afraid - too many other projects to complete) I'll try to remember to report back to this thread, or at least to APUG.

regards
Peter

Bob F. · Jan 12, 2007

As Peter writes, without knowing how wide these LEDs emit, it's difficult to say, but I use a single 3W amber Lumiled run at 1.5W and it works fine with MGIV and Kentmere etc. Pointed at the ceiling (hurts my eyes otherwise) I have tested with preflashed paper to 15 minutes without any sign of fogging.

As implied, I use it for general illumination however and do not point it directly at anywhere paper will lie. I'm pretty sure the lamp you are looking at will work fine if used in that way. Alternately, you may want to go for an orange version to be extra safe. I hate red!

Good luck, Bob.

Sal Santamaura · Jan 12, 2007

I'm using a red OptiLED Festival:

http://www.lightworld.com/optiled/index.asp?id=4

Screws right into any standard (US) lamp socket; 627nm with a 20nm halfwidth. I bounce it off the ceiling and have found it perfectly safe with all papers, including VC. Power supply built in, works automatically with any voltage/frequency. 2.5W consumption. At $25.30 US a bit more expensive than some other DIY approaches, but certainly convenient.

Tim Gray · Jan 12, 2007

I am in the process of putting together a 'portable' darkroom for my tiny bathroom (printed in it once so far!) and picked up one of the red OptiLED Festival bulbs mentioned.

It ended up being $30 with shipping, but has a narrow halfwidth, long life, decent output, and is ready to go. I'm very happy with the purchase, especially for non permanent installation, since I installed it in socket with a clamp, can throw it up wherever it fits, and be done with it.

dylder · Jan 21, 2007

I bought a couple of the superbrights to try. An 8 led and a wide 24. Both Amber. I ran a test using the 8 led about 4' from Arista edu rc paper. 5 minutes and the paper fogged to the point I'm planning to use it for a grey card.

Nice product but definately not a safe light.

dw

wilsonneal · Jan 21, 2007

I don't know the specific unit you're using, but my LED safelights have a dimmer. In the center of my light, which is circular, is a block plastic screwhead, about the size of a number 6 screw. It's a flat head. By turning this screwhead left I can dim the light down all the way to nothing. I did a test with mine and was unable to get Ilford MG to fog at all. Mine are red. See if you have a screw to dim yours down?

Neal

dylder said:
I bought a couple of the superbrights to try. An 8 led and a wide 24. Both Amber. I ran a test using the 8 led about 4' from Arista edu rc paper. 5 minutes and the paper fogged to the point I'm planning to use it for a grey card.

Nice product but definately not a safe light.

dw

BarryWilkinson · Jan 22, 2007

Just for info...

Led's can be dimmed. There are two main approaches...

1. Reduce the LED current. This has the disadvantage that the colour will change.

2. They can be Pulse Width Modulated (cheap chips available) to do this), which is effectively turning them on and off rapidly. The colour stays in spec.

Barry

Mark Fisher · Jan 22, 2007

dylder said:
I bought a couple of the superbrights to try. An 8 led and a wide 24. Both Amber. I ran a test using the 8 led about 4' from Arista edu rc paper. 5 minutes and the paper fogged to the point I'm planning to use it for a grey card.

Nice product but definately not a safe light.

dw

It depends on the paper. I have the Optiled amber. It works great on Ilford papers and fogs Forte. I have a red one for Forte (they recommend a red safelight anyway).

lamda · Jan 22, 2007

Is it worthwhile to have both red and amber?

Mark Fisher said:
It depends on the paper. I have the Optiled amber. It works great on Ilford papers and fogs Forte. I have a red one for Forte (they recommend a red safelight anyway).

Is working under amber light really easier than workin under red? If you had it to do over again, would you bother to get both red and amber lights?

wilsonneal · Jan 22, 2007

Working under red safelights is harder than working under amber. Our eyes are not as sensitive to that wavelength. I'm getting used to it, but sometimes I wish for the old amber lights.
Neal

Mark Fisher · Jan 22, 2007

lamda said:
Is working under amber light really easier than workin under red? If you had it to do over again, would you bother to get both red and amber lights?

Red is OK only because I have a lot of red light. Once I run out of Forte (assuming they really do halt production), I'm back to amber. It is just easier to see with amber.

led safelight - superbrightleds.com?

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