BEST SAFELIGHT... 99.99% safe!!?

Discussion in 'Darkroom Equipment' started by mesantacruz, Jun 13, 2013.

  1. mesantacruz

    mesantacruz Member

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    sorry to be so blatant, and although this has been discussed before, i believe it merits another view. Especially for those building a new darkroom, or just wanting the extra lighting without putting out to much dough.
    Recently, a fellow (clothesontheline) was looking for a cheap alternative to safelights, given he was only gonna need it for a day or two to experiment with pinholes at a camp. Helping him look for alternatives i came across diy LED, to a countless others. Thankfully there is no need for that, as there is a company producing red LED's that do not need any fiddling around with and go into a normal light socket (e26, e27). TURNING ANY LAMP INTO A SAFELIGHT ( i personally think that is awesome). Someone had already done a 15 minute experiment with no visible fogging, and i did a 5 minute test at about 1 foot, with 0 fogging as well (at 635nm, i think it's pretty much impossible).

    examples/comparison

    ^^ here are examples as compared to regular 16 w "in the dark foto lamp" similar to a jr safelight.

    I'm not affiliated, but i think this is so great!!!, i was dreading when my bulb was going to die, as i use an architect type lamp in order to avoid fogging, won't have to do that anymore. Again i noticed 0 fogging.


    120V... please keep this in mind, as this won't be compatible in some countries.

    I was using ilford mg1v rc and fiber

    Link to LED safelight
     
    Last edited by a moderator: Jun 13, 2013
  2. AgX

    AgX Member

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    Some warning: this lamp is seemingly made for 120V. Many members must look out for the 230V Version.
     
  3. mesantacruz

    mesantacruz Member

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    ooops, good call.. i forgot about that i'll re edit... thank you so much.
     
  4. michael_r

    michael_r Subscriber

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    Make sure the fogging test was good:

    http://www.kodak.com/global/en/consumer/products/techInfo/k4/k4TestSafelite.shtml

    I used red LEDs from superbright to make my DIY safelight, but keep in mind while 635nm might be the peak output these are not typically "sharp cutting" so there is typically an emission band around the stated wavelength. Paper sensitivities might not cut off sharply either, and may extend to higher wavelengths than expected. So a good test of safe time is necessary with any light source.
     
  5. jp498

    jp498 Member

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    I've got some LED screw in bulbs from deal extreme. Bright enough red to photograph with my s3 phone. No fogging. I setup a tracklight on the my ceiling for red safelight bulbs and can aim cans where I need it.
     
  6. john_s

    john_s Subscriber

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    I think that this is a good idea. There are parts of the darkroom where you need more light than in other parts. My DIY LED safelights are all over the room. The one near the easel are at a shallow angle so I can see items on the bench but the effective exposure to paper is minimal.
     
  7. Bill Burk

    Bill Burk Subscriber

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    Let's see some prints of shiny chrome objects (like motorcycle engines) which have had the recommended "safelight test" performed on them. It's the degraded highlights that these safelight tests are designed to reveal. The tests are best when you can see side-by-side comparisons with extremes of exposure time. I would more likely believe a safelight safety declaration that suggested the safelight might be safe "for 15 minutes at 4 feet from the paper"

    When you can see one side of the print that had safelight exposure looks just as good as the side that didn't have safelight exposure - then you can declare the safelight is safe for that paper from that distance for that amount of time. I would look - in earnest - for the time when it is not safe. Then I would make sure the paper is only under safelight exposure for less than that amount of time.

    Re-reading, you have given a reasonable guideline: 5 minutes at 1 foot... Let's see what that does to a picture of shiny objects!
     
    Last edited by a moderator: Jun 13, 2013
  8. David Brown

    David Brown Subscriber

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    I've been participating in these discussions for years, now. I just ordered two of the referenced bulbs and I intend to test them outright (using proper procedures) as well as comparing them to my "safe-tested" conventional safelights. I am convinced that LEDs are the future of general lighting. However, I am YET to be convinced that unfiltered light of any technology is automatically safe based on color - especially at the brightness levels that some have claimed. (NOT referring to the OP. This comes up about once a month.) There are a lot of variables.

    I could be wrong! :cool:
     
  9. MattKing

    MattKing Subscriber

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    I have and use as safelights two LED bulb arrays that I obtained through the internet. I have done most of the testing included in the Kodak recommended test (haven't reversed the order of the exposure and the pre-exposure) and the bulb arrays I have have passed that test.

    My concern with recommending them to someone who doesn't understand the need to do a comprehensive safelight test is that the LED bulbs are not designed for darkroom use, so the manufacturers are unlikely to test for that use if there is any change or variation in the production process.

    I think the LED bulbs are great for safelight use for anyone willing to test.
     
  10. Hexavalent

    Hexavalent Subscriber

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    Phillips (Luxeon) etc., do bin their products according to luminous flux and colour output to very fine tolerances. However, I doubt the off-the-shelf consumer, and particularly the ebay shopper can easily purchase binned items.

     
  11. MattKing

    MattKing Subscriber

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    If I had to bet, I would bet that if a manufacturer like Ilford made LED safelights, they would source LEDs that were manufactured to the required tolerances. That is what one pays for if one buys good quality darkroom specific equipment.
     
  12. NedL

    NedL Subscriber

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    I saw ( and participated in ) the same original thread and ordered two of these. They arrived a few days ago. Less than $4 each and the shipping was very reasonable. I have one installed now and used it yesterday. It is mounted about 5 feet above my chemistry and enlarger baseboard in a fixture that has a reflective hood, aimed up at the ceiling. It provides enough light so that I can see what I'm doing. It passed the "coin test" ( yes I know, but if it fails this then there's no point at all, right? ) 10 minutes for: Ilford MGIV, WT MGIV, Adorama VC and Arista.edu VC.

    I made two prints using Adorama VC. The prints have bright white highlights, just off paper white. The first print I made with the light on the entire time. The second print was made with the paper covered with black card while the safelight was on, and I kept it shielded during processing. So this is not quite as rigorous as what Bill suggested, but I can see no difference whatsoever.

    ( However, in the past, it's been the Arista.edu paper that I had problems with... and I haven't done anything except coin test with that so far... I'm hoping it will work. )

    Anyhow, that's my 2 cents after using it for only 1 DR session. The real test is going to be the Arista.edu 11x14 because the way I process it requires quite a bit of time and I need to be able to see what I'm doing. In the past, I made a safe safelight for it by having the only light in the room go through R25 filter. The color of the light from this new led bulb seems very similar to that color to my eyes.

    When the bulb comes, don't be surprised that the bulb part is made from white frosted glass. The red LEDs are inside and you can't really see them.
     
  13. NedL

    NedL Subscriber

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    edit: I should have mentioned that I have calculated pre-flash times for all my papers using a standard height and bellows extension and filter for my enlarger. I will do the Kodak safelight test eventually for all of them.
     
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  15. polyglot

    polyglot Member

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    The thing about LEDs is that they are bandgap devices, they (usually) emit light at exactly one wavelength only. No other wavelengths are possible, because the wavelength is defined by the photon energy, which is defined by the difference in chemical energy levels in the semiconductor.

    Some manufacturers will deliberately mix multiple dopants to broaden the spectrum so this is clearly not true of all LEDs, but the basic simplest cheapest red LED you can make is a single-bandgap device. Obviously one must still test to make sure they don't have a deliberately spread-spectrum device or that the paper they're using doesn't somehow have a tiny bit of sensitivity out to the longer wavelengths.

    Incandescents are fundamentally different in that they're a chunk of hot metal, i.e. a blackbody radiator which produces continuous spectrum all the way up to UV. One applies filtering to make it safe(r) but there is no such thing as perfect filtering cutoffs, etc, i.e. we can achieve only a certain dynamic range between the blocked and passed wavelengths. Attenuating the shorter wavelengths enough for paper to be safe to half an hour means attenuating the longer wavelengths down to annoyingly-dim levels.

    LEDs though, if monochromatic, you can make them as blindingly bright as you want and the paper cannot pick it up. The photon energy is too small to chemically activate the paper, regardless of how many of the photons are present.

    Or to re-state it: there is a bandgap in the LED that produces a photon, and a bandgap in the paper that can absorb the photon. If the energy available to create the photon is less than the energy required to activate an electron in the paper, the electron can never be activated. The number of photons (brightness) is completely irrelevant.
     
    Last edited by a moderator: Jun 14, 2013
  16. cowanw

    cowanw Member

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    FOR USE WITH STANDARD ON/OFF SWITCHES ONLY. Do not use with any type of dimmer, relay or other control circuit.
    The item advertises this caveat. Does one not set up the safelight with the enlarger timer then?
     
  17. David Brown

    David Brown Subscriber

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  18. michael_r

    michael_r Subscriber

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    If it helps at all, my DIY safelight (with LEDs and parts from superbright plus Kodak safelight filters) uses what they call a "Pulse Width Modulation" dimmer. No change in voltage or emission spectrum.
     
  19. AgX

    AgX Member

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    A relay is a electro-mechanical switch. So, no Problem with that. I guess a thyristor in on-off mode would work as well.
     
  20. polyglot

    polyglot Member

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    The LEDs usually having switching regulators in them because the LED itself needs about 1.5V at about 1A, not 115V. If you connect them to a triac dimmer, the regulator switching will turn off the triac and you get no light.

    So no using them with electronic relays (which are also triacs) either. Mechanical relays with metal contacts are fine.
     
  21. David Brown

    David Brown Subscriber

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    OK, I appear to be wrong! I received the red LED bulbs earlier this week. I re-tested my current setup with multiple 0C filters that had tested "safe" before, and it tested safe again. I then used the same procedure using the pair of new LED bulbs, and they, too tested safe.

    (I probably should have tested just one LED bulb first, but I reasoned that if the pair passed, I wouldn't need to test just one by itself. Turned out to be true.)

    I then combined the new LEDs with my current safelights and tested that, and also got a "safe" test. I was both surprised and pleased. I finally extended the test from 7 minutes (using the Kodak procedure) to 10 minutes and still got a clean, safe test!

    I use the Kodak method http://www.kodak.com/global/en/consumer/products/techInfo/k4/k4TestSafelite.shtml. This is very similar to the Ilford procedure http://www.ilfordphoto.com/aboutus/page.asp?n=148.

    The Kodak test goes to 7 minutes. It was a simple step to add another 3 minute exposure to get a cumulative 10 minutes of safelight exposure. All of this was done with Ilford Multigrade paper.

    Disclaimers: Different papers must be tested for, and each darkroom setup, or change thereto, must be tested.

    Therefore, all this proves is that the specific LEDs mentioned by the OP work in my darkroom with Multigrade. It does not speak to all red LEDs, other types of red bulbs, strings of Christmas tree lights, etc.

    My task in the near future is to re-arrange my safelight set-up for efficiency, incorporating the new LEDs (and probably eliminating some of the older units). This new set-up, of course, will require re-testing. I may write all of this up in detail and put it on my old darkroom blog, or maybe here on APUG as an article, or both. The procedure for testing is tedious, but thorough. The most difficult part (aside from distilling the slightly verbose instructions down to the actual steps) is determining what "enlarger exposure is required to produce a light gray tone on the photographic paper with standard processing". In other words, you have to determine the minimum threshold exposure of the paper and make a white-light exposure to push the paper to this level. Then there are two sets of safelight exposures made, one with the threshold exposure made before and one after the safelight exposure. I am guessing this is the most misunderstood (and probably neglected) part of testing safelights.

    Anyway, bottom line: my darkroom is now about 3 times brighter when printing! And safe ... :smile:
     
  22. NedL

    NedL Subscriber

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    In my post above I should have mentioned that it was the *same* print that I made twice before comparing.

    Since then, I too have finished a Kodak-style test with this led light. I used only one, located as I mentioned about 5 feet above my working area in a fixture with a metal reflector, aimed up at the ceiling. I tested Adorama Brand VC paper, with up to 7 minutes before and after threshold exposure. It tested safe. I suppose to be 100% forthright, I should mention that I preflash paper through a green filter, and that's what I did for these tests. Next up will be Arista.edu VC paper, which my old safelight setup caused to fog.
     
  23. PeterB

    PeterB Subscriber

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    For those of you who have purchased this product and still have the original box it came in, what is the maximum AC voltage these LED globes are rated to ? We use 230V in OZ but there is no mention of the rating on the web page. Some of the other LED globes on that site are rated to either 110V or 110/240V but they don't come in red.
     
  24. clayne

    clayne Member

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    I also have used LED safe lights (superbrightleds.com) for a few years now and never had issues with fogging. There's quite a bit of data on this in already existing threads but LED bulbs tend to be narrowband which is what one wants. I always use red, never OC or equivalent.
     
  25. NedL

    NedL Subscriber

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    The box says "Voltage:110VAC". Sorry :sad:
     
  26. Simonh82

    Simonh82 Member

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    I recently purchased one of these http://www.amazon.co.uk/dp/B00C665QYQ/ref=cm_sw_r_an_am_ap_am_gb?ie=UTF8, which has 24 LEDs in a single bulb. It is equivalent to about a 40-50w incandescent bulb and is completely safe. I've been using it for lith printing with total times for the paper bring exposed to the light of almost an hour. This includes Forte polywarmtone which can be dodgy even under a dim red safelight for long exposures.

    Having previously worked with one very dim 15w bulb behind thick red plastic it is a joy to use. There is no need for a safe torch from judging the shadows of my lith prints, I can see them come up clearly. The bulb gives a 120 degree angle of coverage which covers the whole of my darkroom nicely.

    There is no way I would ever go back yo incandescent bulbs.