Kodak safelight bulb wattage

[pbromaghin]

The darkroom is almost ready to go but I would like a little more safelight. I have 2 more Kodak torpedo shaped amber lights but one needs a bulb. They say to use max 15 watt. Is this guideline to protect paper from excess light or to prevent a fire hazard from excess heat? With today’s 15 watt LED bulb producing the luminosity of yesterday’s 100 watt incandescent, I’m not sure what to buy.

 

[MattKing]

That caution is based on the light output, not heat.
Consider using a red or amber LED bulb in there, but not one that puts out as much light as a 100 watt incandescent bulb.
And whatever you do, make sure you test!
https://www.kodak.com/content/products-brochures/Film/KODAK-A-Guide-to-Darkroom-Illumination-K-4.pdf

 

[mshchem]

There's still some sellers with 15W incandescent bulbs on Ebay. I bought a bunch of 15 and 7 1/2 W bulbs when GE gave up lighting. I wish I had bought more.
I love LED lighting, but I still like the old ways for somethings.

I would try Matt's suggestion, the Kodak beehive lamps don't have much light.

 

[MattKing]

FWIW, I use a red LED rope light that was marketed for Christmas time sales.
It provides the best and brightest safelight illumination that I have ever worked in - better even than the Thomas sodium vapour discharge lamps in the commercial darkroom I worked in many years ago.
But you do have to perform the full Kodak safelight test to ensure that it is safe - the rope lights aren't designed with the knowledge that they might be re-purposed that way.

 

[Molli]

These are still readily (and cheaply) available in Australia from supermarkets to hardware stores to $2 Shops (I know, SO helpful to you on the other side of the world!) At any rate, they're still made to go in appliances. I've always referred to them as pilot lights, so a search for "appliance light" or "pilot light" should yield results for you. The ones I buy have a standard bayonet fitting and I use it directly in the ceiling fixture with a Kodak beehive amber cover. I'm still using the same light bulb I bought for this purpose back in 2010.

 

[Ian C]

Consider

Westinghouse 4513400 Pack of (1) 5 Watt Soft White A15 | Build.com

I’ve used these in 15-watt equivalent WARM WHITE lamps in Kodak “bullet” style and 5” x 7” Premier safelights with good results. The apparent color of the light seems similar to that of an incandescent lamp. At 5 watts power consumption, they produce no discernable heat.

The “15-watt equivalent” rating means that these produces approximately the same light output as that of the older 15-watt incandescent lamps that they replace. Choose the WARM WHITE version for the color of light closest to that of the original lamps.

Similar lamps in the US/Canada are available at sellers such as Home Depot.

 

[loccdor]

I have 3 watt actual power consumption yellow LED bulb "bug lights" around the outside of the house and shed that produce a nice low level of light for just being able to not bump into things at night. I suspect the actual wattage of an LED you would use as a safelight would be somewhere around there.

 

[pentaxuser]

I was thinking of exchanging my Ilford 902 for some red lights in the hope that with the right wattage the 1978 version of Fay Dunaway might appear to help me in the darkroom where she clearly had some experience. As long as the only killer image she prints is that of Jerry Lee Lewis I should be OK

pentaxuser

 

[xkaes]

Whatever bulb you decide on, make sure you test it with your paper.

 

[DWThomas]

Whatever bulb you decide on, make sure you test it with your paper.

Yes, that's the key. I use one of those golf ball on an E26 base red led bulbs that were widely touted a few years back. But working with green sensitive X-ray film it was necessary to put a Rubylith filter in the fixture. I also added a home made attenuation filter using a sort of halftone pattern inkjet printed on transparency material.

In a quick look through some big box store websites I see a few suitable incandescent bulbs which fall into the category of "appliance bulbs." No idea how much longer those may be available, but so far, so good.

 

[mshchem]

When I lived out in the country, our development used sodium vapor safelights. I didn't bother blocking the front window when printing .

 

[pbromaghin]

Thank you for all the help!

After reading through the replies I went to Lowe’s and picked up a couple soft white LED bulbs, 11 watt equivalent. There are 4 safelights, 1 bulllet and 3 half-cylinders, in about a 12ft x 8ft space. I plan to add these 2 bullets.

There are still some light leaks to seal up and the outermost layer of the light-maze entrance to put up and it will be ready to test.

 

[ic-racer]

I use 7.5 Watt E26 base lamps in my Kodak safelights.

 

[Doremus Scudder]

Kodak safelight test here: https://www.kodak.com/content/products-brochures/Film/KODAK-A-Guide-to-Darkroom-Illumination-K-4.pdf

Have fun,

Doremus

 

[callsign_BULL]

I'm looking into adding another OC Kodak Model A (beehive) to my small bathroom darkroom, where I now have one direct OC Model A screwed into a ceiling socket. I get decent working light but might like a little more (I do miss my old OA filtration with graded paper). When I checked my supply of 15w bulbs two were 65 lumens, two were 100 lumens, and one was an unknown. ??? I've never found anyone that stated the intended luminosity at the specified distance - not Kodak nor Ilford nor Du Pont, not even my old Photographers Mate 3 & 2 and 1 & C pubs. I guess the only thing to do is find as many different brand 15w bulbs as possible and take an average. I do successfully use a 180 lumen/25w bulb in the ceiling lamp, 63" from the work area. I SWAG'd that using an inverse square calculator ( https://byjus.com/inverse-square-law-calculator/ )

BULL//

 

[Kilgallb]

I replaced my 15W incandescent bulb in my Kodak safelight with a the lowest wattage LED lamp I could find. the LED lam was rated as the same as a 20W incandescent. It was brighter than with the old bulb so I did a test paper test (25 cent piece on paper) and no issues.

 

[xkaes]

I have a supply of household socket incandescent 25w, 15w and 7.5w bulbs. Whatever bulb you use, you can always vary its intensity -- after testing for safety for the paper, of course -- by moving the safelight closer or farther away. And there's always the option of adding a dimmer switch if you can't find low wattage bulbs.

 

[xkaes]

I replaced my 15W incandescent bulb in my Kodak safelight with a the lowest wattage LED lamp I could find. the LED lam was rated as the same as a 20W incandescent. It was brighter than with the old bulb so I did a test paper test (25 cent piece on paper) and no issues.

That's much better than doing nothing, but here's a more accurate approach -- and it doesn't cost 25¢

http://www.subclub.org/darkroom/henry2.htm

 

[MattKing]

See post #2 in this thread for the link to a comprehensive safelight test, that is much more effective than the simple quarter on the paper test referred to above.
And by the way, it isn't the wattage of the bulb, it is its lumen output and the spectral distribution of that light. The old incandescent bulbs were a lot less green and blue than many LED bulbs, and photographic paper is sensitive to green and blue.

 

[callsign_BULL]

To better pursue the wattage vs lumens issue I emailed Ilford Tech this morning, and in less than 2 hours I got the following back:

"Dear ...,

We don't quote lumens values for the following reasons. There is variation in the output of lamps and variation in the density of the safelight filter. The cut-off wavelength of the safelight filter is even more significant than the overall lumen level and this will not be indicated by a photometer. Also, generally available photometers are notoriously variable at low light levels and many do not agree precisely on their relative sensitivity to different wavelengths of light. This is much less significant when measuring daylight/studio levels but can make a significant difference when measuring coloured light.
Please see:
https://www.sciencedirect.com/topics/engineering/photometer#:~:text=Spectral Response Considerations
then click on "Read More" to see IX.B.

We would rather recommend a mode of use test; using the safelight and the product to establish whether working times are safe.
Please see:
https://www.ilfordphoto.com/testing-your-safelights/
Regards,
David Abberley

Technical Services
technical@harmantechnology.com"

So, bottom Line: Test whatcha got. My search and average of 120v, 15w, frosted bulbs from known US companies is 91 lumens - I'll use my 100 lm GE bulbs and put in a small supply of identical ones.

BULL//

 

[koraks]

I got the following back:

I think they misunderstood your question. They appear to have reflected on the question "what is the number of lumens that constitutes a safe light level", and not "what bulb light rating in terms of lumens should I be looking for when purchasing a white bulb to sit behind a safelight filter." The answer to the safelight level in lumens is indeed that it's practically not possible to measure it. The answer to the question what bulb you should get in terms of 'lumens rating' (put simply) would be "something close to what's originally specified". However...if you reason that one out, you'd still end up with the same conclusion, i.e. you need to test under your specific conditions. After all, even if the bulb mounted behind the safelight filter is of the 'correct' lumen rating, it has an appropriate (black-body equivalent) spectral output etc, it still makes a difference how far you've installed it from where the paper is handled, what colors your walls and ceiling are, etc.

 

[UnderwoodPhoto]

Light or heat? Might be both. A 15 watt incandescent can get quite hot in the small enclosed fixture, or more wattage is unsafe for the paper. I would try (and bet it is ok), an orange 40 watt party LED bulb. Yellow LED bug lights have too much green in them so dont bother.

 

[wiltw]

A 15W incandescent bulb from Westinghouse is stated to output 90 Lumens; from Sylvania it outputs 65 lumens; from GE it outputs 100 lumens

 

[callsign_BULL]

Yup, I dipped for four Westinghouse 15w/120v/90 lm this afternoon as my new standard. I demurred on the 100 lm GE because no voltage was stated. Testing begins Monday, using Ansel Adams' procedure as it is simple and doesn't involve a densitometer, just a Zone VII comparison.

BULL//

 

[rcphoto]

I have a relatively small darkroom and use a 7.5w incandescent bulb in my patterson safelight. It is also rated for 15w but even the 7.5 seems like a lot of light.