How safe is safelight?

I could do a test on my own but I don't want to waste paper. Say I use red LEDs for my safelight. LEDs should be really pure red light with no real shorter-wavelength component. If the paper really isn't sensitive to red, do I have to worry about how bright it is? If not, might as well go bright, right? I saw some high-powered red LEDs at Dealextreme and it got me wondering how much exposure paper could get.

It'll take about 10-20 cents worth of paper to test. You should test any safelight you make or buy.

Depends on the light and the paper. I've used LED safelights that are bright and safe, but I like graded papers, so they can tolerate a brighter safelight than VC papers.

A safelight test is not a waste of paper. If you get dull highlights because of excessive safelight exposure, then that will be a waste of paper.

Is the LED red emitting or broad spectrum with a red filter? If the paper is 'red blind' in either case it should be OK at a distance, but not full intensity at close distances. As to wasting paper, not doing a test waste paper. Take a strip 1 inch by 4 inch, with just the safe light. AT one minute place the penny, at 5 the nickel at 10 the dime at 15 develop the strip. If you can't tell where any coin was you are safe.
if you can only tell where the penny was you are OK.

TR

trexx said:

Is the LED red emitting or broad spectrum with a red filter? If the paper is 'red blind' in either case it should be OK at a distance, but not full intensity at close distances. As to wasting paper, not doing a test waste paper. Take a strip 1 inch by 4 inch, with just the safe light. AT one minute place the penny, at 5 the nickel at 10 the dime at 15 develop the strip. If you can't tell where any coin was you are safe.
if you can only tell where the penny was you are OK.

TR

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*****
A short flashing exposure should be given first in order to destabilize the halides or a safelite which passes the above test might still not be completely safe. Regarding red safelights, I have always found it the most difficult light in which to judge a print. But sometimes one has no choice--according to Freestyle, the Russian-made papers need a red safelight and no other.

As others have advised, do a test, and the simple test described by trexx and Johns addendum works. I would only add to block up your enlarger lens and turn it on for 20 second or so so you are testing it for leaks and bounces from it at the same time. You can get many tests out of a single sheet, just save the short sheet in your box for the next testing time.

It is important to do the testing with papers you intend to use. If you bring a new paper into the darkroom test it. Some papers are fine under some kinds of "safe" light, and others are prone to problems with the same kind or intensity. You should test every so often anyway, but especially with a new set up or new paper.

The best reason to test is because most safe light problems aren't that apparent. You go on printing for a long time wondering why Goldfarb's highlights are so sublime compared to yours, because yours are missing just that little extra something, while you go through different developers, papers, films, toners, and all the other magic bullets, and the menacing secret was hanging over your shoulder the whole time.

That's the long way of saying a good printing regimen beats a magic bullet every time.

Hello BetterSense;

a LED *will* emit light at both shorter and longer wavelengths. You need to get the manufacturer's data sheet. They usually have a graph where you get the wavelength on the X axis and intensity on the Y axis. It's usually a bell shaped graph. So, you see, a LED emits with a peak intensity at it's nominal value, but you really get a band of wavelengths. OTOH, if the intensity at the shorter wavelengths is very low it can be very safe for prolonged exposures. It all depends on the paper, the actual intensity and the distance between your paper and your safelight. One more thing, you should check the "safety" of your safelight with *every* paper you use. Not all papers have the same spectral sensitivity.

To understand how a safelight works, take a look at the wedge spectrogram in this post from Photo Engineer--

(there was a url link here which no longer exists)

See where the curve dips toward the right end of the graph? That's the ideal wavelength for a safelight, because that's the wavelength that the paper is least sensitive to. Notice, though that it doesn't go all the way to zero--the emulsion is just less sensitive to that wavelength than it is to other wavelengths, so you still want to limit exposure to that wavelength by testing the safelight to be sure that it's at a safe level and by keeping paper in the box or the paper safe until you're ready to expose it, and then move it to the developer tray as soon as possible after exposure, or if you plan to expose a stack of prints and develop them in a batch, then keep the exposed sheets in a safe place until you're ready to process.

Q: How safe are safelights?

A: I've been in the darkrooms for years, and I've never gotten a burn from a safelight yet.

Actually, LEDs should be quite safe, and I've been using several higher output red LED lightbulbs with no issues.

Red LEDs generally make good paper safelights. Those with 660nm and longer wavelengths can generally be used with orthochromatic film, at least if the intensity is not too high. The sensitivity of bromide paper and orthochromatic film does not suddenly drop to zero in the red. It just declines a lot, and some sensitivity still exists to red and orange light. But that sensitivity is low enough to give you decent working time with a safelight that isn't too bright. Actually, the safelight can be bright enough to give you a really good working light with most materials. You should really test your safelight setup to be sure, and testing is easy. First find a negative with a lot of bland gray areas (like sky) and not much detail. Determine the exposure for a good print. Get out a bunch of coins and set them next to the easel. Turn out the lights (no safelight), load a sheet of paper into the easel, and make an exposure. After the exposure is made and still in the dark, place the coins in a line on the paper in some gray area. Cover all but the first coin with a piece of cardboard or other lightproof material. Turn on the safelight. After 5 (or 10 if you're optimistic) minutes, uncover the second coin. Continue like that until all the coins have been uncovered. Then develop and fix the print. The first segment to show any hint of an outline of the coin is 5 (or 10) minutes too much exposure to your safelight.

I'm using a one-watt Red Luxeon LED as a safelight and it works great and it's pretty bright just hanging there above my trays. I did do a simple safelight test with it and couldn't detect any fogging.

Where did you get the LED?

BetterSense said:

If the paper really isn't sensitive to red, do I have to worry
about how bright it is? If not, might as well go bright, right?

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If you want Bright go Graded. A very well lit darkroom may
be had using yellow to orange for safe light. Sensitive to
blue only, Graded papers allow for safe light color with
in the green portion of the spectrum; the eyes most
sensitive color. Dan

I use a mix of LEDtronics Red Safelights (wonderful, wonderfully expensive) and Nuarc Bubblites (wonderful, wonderfully cheap). Both are red.
Very red. As everyone else has said, all you need is a test strip's worth of paper or two.. I believe there is a Kodak tech pub. on testing your safelights.. The LED safelights are extremely safe. I trust them more than the bubblites, but the bubblites are generally much further away (with 2 8-10 watt bulbs inside. They get bright as well.)

I can tell you that the red LED's don't fatique you as much, which is very nice.

What makes you think that you are really benefitting in any way from having a safelight? Dark is very workable. Dark is very energy eficient. A print needs to be properly exposed and fully developed. Time and temperature works very nicely and in a straight forward manner without using any safelight at all. Instead concentrate on having a viewing light that is nice and bright for viewing the print when it has been fully developed and a second light that has been set to the intensity of the lighting conditions the print is intended to be viewed under.

SAFELIGHTS FOR NEVER!

Claire Senft said:

What makes you think that you are really benefitting in any way from having a safelight? Dark is very workable. Dark is very energy eficient. A print needs to be properly exposed and fully developed. Time and temperature works very nicely and in a straight forward manner without using any safelight at all. Instead concentrate on having a viewing light that is nice and bright for viewing the print when it has been fully developed and a second light that has been set to the intensity of the lighting conditions the print is intended to be viewed under.

SAFELIGHTS FOR NEVER!

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Actually, I sometimes print in my darkroom with the regular lights on. You just have to work very quickly.

Here's the link for the Kodak safelight test: http://www.kodak.com/global/en/consumer/products/pdf/k4.pdf

Are those Nuarc Bubblites a discharge lamp?

JBrunner said:

Actually, I sometimes print in my darkroom with the regular lights on. You just have to work very quickly.

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I have done that before. It only really worked for one image though. My limited edition of Blind Man in a Coal Cellar Looking for a Black Cat That Isn't There.


Steve.

Blind Man in a Coal Cellar Looking for a Black Cat That Isn't

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- A new entry for the Turner prize.

I have always thought that the green safety light for film was something special for the film. Then I recently looked at the sensitivity of the human eye which peaks at yellow/green and realised the safelight is not for the film so much, which is very sensitive to green, but the eye of the viewer. We see better in green light. Slightly OT I know.

Murray

Kirk Keyes said:

Are those Nuarc Bubblites a discharge lamp?

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Not sure if I know what a discharge lame is (like sodium vapor/thomas safelights?)

These are 'lith-tape red' plastic, with a metal back and ceramic bulb holder. The bulb is a standard household bulb, I use 10 watt bulbs. Mine holds two bulbs but I usually only need one 10 watt bulb. Anything more than that and they get a little too warm to the touch.

I even have one mounted over my developing trays without it's red cover. It's just two bulb sockets, one with a 60watt bulb and one with a LEDtronics safelight screwed in. I can turn the 60watt bulb on after I print a test strip to evaluate it, it's pretty handy.

The plastic gets brittle and can crack, but some red lith tape holds it all together. I bought a vacuum pump (huge green thing, must have gone to a nuarc process camera or the like) and got three of these lights thrown in the deal.

Nuarc also has/had a long fluorescent bubblite safelight, three feet long I think. Very heavy, at least from the descriptions i've read. They may have had an incandescent version too, i'm not sure.

That is cool, I always thought it was due to the film too.
I've always wanted to try DBI..

Murray Kelly said:

I have always thought that the green safety light for film was something special for the film. Then I recently looked at the sensitivity of the human eye which peaks at yellow/green and realised the safelight is not for the film so much, which is very sensitive to green, but the eye of the viewer. We see better in green light. Slightly OT I know.

Murray

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Philip - thanks for the description.
A neon light is an example of a discharge lamp.

I heard it won the Turner, but they couldn't read the artists signature on the front so they didn't know who to give the prize.

Tom Kershaw said:

- A new entry for the Turner prize.

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