Safelight Help

MamiyaJen · Sep 26, 2012

Hi folks,

My safelight is a bit on the crap side;, in that it gives out very little light. Plus i've just spent quite a while setting my room up to print some images only for the bulb to blow

Anyway, can i use an ordinary red bulb in my ceiling light or will that give out the wrong kind/too much light? Not sure I'll be able to get a bulb for my safelight in town tomorrow and don't want to mess around putting everything away again. If i can use a normal red bulb i know i can get one tomorrow.

Help much appreciated as usual

Chris Douglas · Sep 26, 2012

The only way to know is to test. Kodak publishes a good test.

cliveh · Sep 26, 2012

Have you thought about a R10 strip light. I use one and find it quite good. By the way, there are advantages to dark darkrooms, as you can see the image on the baseboard more clearly.

MamiyaJen · Sep 26, 2012

cliveh said:
Have you thought about a R10 strip light. I use one and find it quite good. By the way, there are advantages to dark darkrooms, as you can see the image on the baseboard more clearly.

Do you mean using no light at all? I did think about it. If i can't get a bulb tomorrow I might try it.

Rafal Lukawiecki · Sep 26, 2012

A "normal" household red lightbulb will almost definitely cause trouble when used on its own. Used with a safelight filter, that is not too old, should be OK. You might have a bit more success with a household red LED, especially one not over 2W (unless you have a large darkroom allowing for brighter ones) but you really cannot be sure at all without some testing, as many LEDs produce more than just the red light. Search APUG for many LED safelight threads, there is a lot here.

The Kodak test takes only 15 minutes to do and it will tell you if your safelight is really safe. Avoid simpler tests, like the coin test, as they do not paint the full picture, ie you may think you are safe because paper is not fogging, but you may be getting just enough exposure from an unsafe safelight to make it impossible to get good contrast repeatably.

Safe safelight is very important, otherwise you will be going in circles trying to get a good print. Second to that is making sure your enlarger does not leak too much light, I would think.

cliveh · Sep 26, 2012

MamiyaJen said:
Do you mean using no light at all? I did think about it. If i can't get a bulb tomorrow I might try it.

No I didn't as you need to be able to see what you are doing.

wiltw · Sep 26, 2012

Kodak officially recommends...

OA greenish yellow is for B&W contact/duplicating films
OC amber is for B&W print making
Red is only for some blue-sensitive materials
Light red is for slow orthochromatic materials
Dark red is for fast orthochromatic materials
Dark green is for some B&W panchromatic materials
Green is for some B&W infrared materials
Dark amber is for color print materials

Generally it is best to handle panchromatic B&W film in darkness; same for color film.

Mainecoonmaniac · Sep 26, 2012

I bought a string of red christmas lights and they work great for BW paper. $12 on ebay.

MamiyaJen · Sep 26, 2012

cliveh said:
No I didn't as you need to be able to see what you are doing.

Actually gave it a go and did fine haha

nworth · Sep 27, 2012

First, good safelights usually do not put out much light. The Thomas safelight of a few years back (low pressure sodium bulb) was an exception, and it often put out too much light to do things like focus the enlarger. Paper sensitivity does not simply cut off at some wavelength, it just markedly decreases. A good safelight keeps exposure insignificant for reasonable handling times while providing enough light to work. As you have discovered, safelights do change over time. You should perform the Kodak safelight test or its equivalent every so often just to be sure you are still safe. I strongly advise that you simply buy another safelight - one designed for the purpose. Modern papers require the equivalent of a Wratten OC, amber, safelight - others emit too much green for safety. Some papers recommend the equivalent of a Wratten 1A, light red, safelight. A simple red bulb may or may not work. Even if it works, it will probably provide less working time than a real safelight, and it may very well age rapidly. If you have one handy, you can test it.

kevs · Sep 27, 2012

Hi MamiyaJen,

I would be careful with a red-coated tungsten bulb; there may be an area near the base that isn't coated and the coating may not block the lower green wavelengths. You can check by using a CD or DVD as a diffraction grating. Reflect the light from the bulb and if you can see any green or blue light in the reflection, your bulb is not safe for normal paper.

Cheers,
kevs

RalphLambrecht · Sep 27, 2012

http://www.waybeyondmonochrome.com/WBM2/TOC_files/SafelightTestEd2.pdf

David Brown · Sep 27, 2012

MamiyaJen said:
... can i use an ordinary red bulb in my ceiling light or will that give out the wrong kind/too much light?

<sigh> Maybe. Probably not. (there was a url link here which no longer exists)

MamiyaJen said:
Not sure I'll be able to get a bulb for my safelight in town tomorrow... If i can use a normal red bulb i know i can get one tomorrow.

You may have an exotic safelight with an exotic bulb, but most of them take a rather standard, but low wattage bulb. It is the filters that make them "safe". The vast majority of the time, if you can find a suitable red bulb, you can find a useful replacement for the safelight.

Roger Cole · Sep 27, 2012

Once you find them, if they're hard to find, stock up. I have a pack of four replacements for my Patterson. Anything that normally wears out and you can't live without if it goes out, you should have a spare.

kevs · Sep 28, 2012

Or get a half a dozen high-brightness red LEDs, solder them in parallel on a piece of Veroboard and connect a 3 volt battery. Stick it on the ceiling with some blu-tack and Bob's your auntie!

Cheers,
kevs

Barrie B. · Oct 2, 2012

Red LEDS for Darkroom safe-light .

kevs said:
Or get a half a dozen high-brightness red LEDs, solder them in parallel on a piece of Veroboard and connect a 3 volt battery. Stick it on the ceiling with some blu-tack and Bob's your auntie!

Cheers,
kevs

Greetings Kevin ; Will any 'high brightness' red leds do ? How do I find out which prong of the LED to solder to the next one ? Is there a polarity problem ? Can a led be damaged when soldering . ? ...............................................Cheers Barrie B. Melbourne - Australia .

GRHazelton · Oct 5, 2012

Has anyone tried using the low wattage compact flourescent bulbs? I have a large Kodak safelight, 9 x 12 I think. I don't remember what wattage is recommended for it, probably 25, which happens to be lowest wattage equivalent CF I saw listed. I aim the safelight toward the white ceiling, would this let me use a higher wattage bulb safely? The filters are fairly new.

K-G · Oct 5, 2012

GRHazelton said:
Has anyone tried using the low wattage compact flourescent bulbs? I have a large Kodak safelight, 9 x 12 I think. I don't remember what wattage is recommended for it, probably 25, which happens to be lowest wattage equivalent CF I saw listed. I aim the safelight toward the white ceiling, would this let me use a higher wattage bulb safely? The filters are fairly new.

For those papers that can take an orange safelight ( for example Ilford MGIV and Adox MCC ) I have used a fluorescent bulb with very low wattage but high light output for several years. It is cased in a closed lamp holder with an orange filter. Absolutely no problem ! Like you , I aim the safelight towards the ceiling.

Karl-Gustaf

cliveh · Oct 5, 2012

GRHazelton said:
Has anyone tried using the low wattage compact flourescent bulbs? I have a large Kodak safelight, 9 x 12 I think. I don't remember what wattage is recommended for it, probably 25, which happens to be lowest wattage equivalent CF I saw listed. I aim the safelight toward the white ceiling, would this let me use a higher wattage bulb safely? The filters are fairly new.

That's what an R10 is, an encasement for a low wattage flourescent bulb. It works fine.

cmacd123 · Oct 6, 2012

Barrie B. said:
Greetings Kevin ; Will any 'high brightness' red leds do ? How do I find out which prong of the LED to solder to the next one ? Is there a polarity problem ? Can a led be damaged when soldering . ? ...............................................Cheers Barrie B. Melbourne - Australia .

JOBO once made a Small Safelight/flashlight with a carefully selected LED, which was designed to work with most B&W and _Colour_ paper that was available at the time. (Don't know if the newer papers are still safe for that unit) I don't know if they published the wavelength of the LED that they used.

A general RED led should work, but you should try to get a datasheet and compare the wavelength with the Wavelengths that the paper you are using is sensitive to.

LEds come with one lead longer than the other, and generally there is also a notch in the case near one lead. The Leds should be wired Anode to cathode. and the current limited - Generally by a series resistor. Again The manufactures data sheet for the LED you use should show which lead is the anode and cathode. It will also show the Maximum current.

The LEDS like most semiconductors do have a limit of the heat that they can be exposed to. Again Read the data-sheet.

http://www.futurlec.com/LED/LED3R.shtml is an example of the Data that is avaiable on a typical Low cost LED.

kevs · Oct 6, 2012

Barrie B. said:
Greetings Kevin ; Will any 'high brightness' red leds do ? How do I find out which prong of the LED to solder to the next one ? Is there a polarity problem ? Can a led be damaged when soldering . ? ...............................................Cheers Barrie B. Melbourne - Australia .

:Hi Barrie, I replied a few days ago to your private message; regret I didn't see your post here.

Cheers,
kevs

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