What is the aversion to using a proper safelight?

[DREW WILEY]

I work in total darkness when tray developing film or working with color paper. I've had even small
red LED's fog shadows with certain film. My LED timer is now UNDER the sink where the film can't
see it at all. For black and white paper, I use an old Kodak barrel safelight, but it's connected to a
rubberized (shockproof) footswitch, which I momentarily step on when needed. I've heard plenty of
stories about Thomas safelights fogging things.

 

[Ken Nadvornick]

The reason some red LEDs and the Thomas sodium safelights fog is because they also emit small amounts of non-safe wavelengths.

Look at the emission spectrum of a low pressure sodium tube. See all of those small blue and green spikes beyond the dominent sodium doublet? There's no way to visually detect those in the flood of monochromatic orange light, but they are there. Remove them (using a Roscoe #19 Fire filter) and the fogging disappears.

Same for the red LEDs. Remove them (using a Rubylith filter) and the fogging disappears.

Try this. Hold up the business side of an ordinary CD disc to your red LEDs (or to a Thomas tube) and look at the discreet wavelengths that are reflected. I'll bet if you look carefully you'll see a few narrow green and/or blue stripes mixed in with the red or orange. I know I did.

My red LEDs showed small telltale green bands and my Ilford MGIV VC paper was faintly fogging. The Rubylith cured that out to 60 minutes tested. My Kentmere Bromide graded was severely fogging under the Thomas. The Roscoe cured that out to 30 minutes tested.

Ken

 

[Robert Hall]

If you really want to go down this road, David, we could talk about those who spend thousands on a new camera setup but wont spend $250 on a decent workshop or class. (Where, I might add, they would learn that a red screen from an iphone just won't work as a safelight.)

 

[E. von Hoegh]

"Hold up the business side of an ordinary CD disc..."

Clever!! I have a couple hundred spectrographs I never thought of! Thanks.

 

[dpurdy]

I have all the different safe lights, including the thomas but I am settled on LEDs and a few red christmas bulbs. The Thomas makes a lot of noise. I hate that. The red LEDs are the best.
Dennis

 

[Leigh B]

...the Thomas sodium safelights fog is because they also emit small amounts of non-safe wavelengths.

Could you explain the mechanism, please. Sodium is monochromatic (two closely-adjacent spikes).

- Leigh

 

[Leigh B]

The Thomas makes a lot of noise.

Then it's broken and needs to be fixed. Mine makes absolutely no noise.

I have encountered other posts where users report noise.

- Leigh

 

[Ken Nadvornick]

Could you explain the mechanism, please. Sodium is monochromatic (two closely-adjacent spikes).

Yes, but I believe that there is more than just sodium contained within an LPS tube. This is from memory, but I believe there is some neon and argon in there as well? Perhaps other stuff also? I know that the HPS lamps show a far larger number of more intense blue spikes due to the presence of mercury in those tubes.

So I'm assuming, but do not know for a fact, that the additional emission spikes are impurity-related, intentional or otherwise. If somone knows more about this, please ring in. I'd love to hear more.

In any case, take a look at this link by Brian Niece, Associate Professor of Chemistry at Assumption College in Massachusetts. It details some of his real-world classroom lab results of capturing various emission spectra. His recording of the emissions from an LPS discharge tube are shown in the 4th example down the page. (The photos and graphs will all enlarge if you click on them.)

Note the third photo. It distinctly records the non-doublet spikes on both sides of the primary D-line emission. Those green and blue spikes are the ones I'm referring to. They are far weaker than the doublet, but are nevertheless present.

Given that after I applied the Roscoe #19 Fire filter (with no other changes to the system) my bromide paper fogging essentially vanished, I'm concluding those types of spikes were the culprits.

Ken

 

[Leigh B]

Hi Ken,

Assuming the report is as you stated (I did not read it), I can find no other source online to substantiate it.

All of the other reports from various government agencies show only the Na line at 589nm and an IR line at 819nm (much reduced).

For example, quoting from a report entitled "SPECTRAL SIGNATURES OF NIGHTTIME LIGHTS":
"High and low pressure sodium vapor lamps have very little variability. Both have strong emission
lines at 819 nm. The low pressure sodium lamp has only one additional emission line of any
consequence, at 589 nm." (emphasis mine)

Here's a spectrum for the SOX bulb from a company that makes them:


- Leigh

Ref:
SPECTRAL SIGNATURES OF NIGHTTIME LIGHTS, Christopher D. Elvidge
NOAA National Geophysical Data Center, Boulder, Colorado USA

Abstract
A spectral library is being built for a wide range of lighting types.

URL: http://www.asdi.com/getmedia/05be99...CTRAL-SIGNATURES-OF-NIGHTTIME-LIGHTS.pdf.aspx

 

[Mark Fisher]

LEDs can be quite safe and much brighter....and inexpensive. Why would anyone use a traditional safelight

 

[David Brown]

LEDs can be quite safe and much brighter....and inexpensive. Why would anyone use a traditional safelight

Good question ...

 

[Michel Hardy-Vallée]

There have been numerous threads on this forum over the years with similar things. People will spend money on cameras, film, paper, chemistry, tanks, trays and enlargers, and then want the best lenses, but won't buy a proper safelight. Seriously, they aren't rare. What is the deal?

There is also the LED school. I understand and appreciate the fact the the right LEDs will work, but I perceive that many folks end up spending as much on obtaining and testing the correct LEDs as they would have on just getting a real safelight. Safelights can be had used, just like the enlargers, lenses, tanks, trays, etc.

Yes, safelights are rare.

I live in a major metropolitan city and I can't find anymore the large orange globe model I used to have, only tiny dark red ones, which are hard on the eyes for nothing when you're printing on graded paper.

Like every incandescent bulb, they burn. In addition, unlike LEDs, a few knocks when the lamp is stil warm, and the filament is bust. When you have a makeshift darkroom that you must tear down every time you're done, things get shuffled around.

LEDs have a gazillion-hours life expectancy, and are not sensitive to knocks. Plus, when you buy from a decent supplier, you get a spectrum graph that you can match with your papers.

I now have an exceedingly bright and clear amber light that works even with VC, and makes B&W printing as easy on the eyes as working with white light, and a red one for when I need to work with ortho materials.

I got two of each (something everybody should do, no matter what kind of safelight you're using), so that whenever the first one breaks, I have a spare.

 

[Roger Cole]

My order from SuperBrightLEDs arrived yesterday. I should have time to play with them this weekend. I'll get back to you on whether they're brighter while being just as safe (the reason I decided to try them.)

But safelights are far from rare. If you only look locally than many things are rare, including film other than 35mm consumer C41 and even that can be rare. A quick check on Freestyle turns up their Arista brand in both OC and red (looks identical to my older Patterson, uses common as dirt 7W bulbs available in packs of four for a few bucks at Home Depot as well as other places or online) and Premier models with interchangeable filters in both 5x7 and 10x12, plus the sleeves that go over fluorescent tubes (no idea how safe those are though - not very convenient unless the tube fixtures are already there) and bulbs and filters for the Thomas.

B&H has a selection of Arkays, Dorans, Patterson (a different shape than my older one,) Yankee (careful with that one - I had one of those years ago with a black body which was fine, and then later a white one which was NOT fine, at least not with the standard filter. Very bright and lots of fog. It comes with a VC filter too but if you get it used you may not know that. The VC filter is fine but gives up all the brightness advantage of the white reflector body) and various colored simple bulbs.

eBay or the various photo forums will turn up others quite easily.

Use LEDs because they're brighter and safe and durable, or because they're cheap. But safelights designed as such are anything but rare. They're as readily available as paper and developer.

 

[Sirius Glass]

Sometimes there no limiting bounds on stupidity.

 

[Roger Cole]

Roger, for an extra few $ you can also put a dimmer on it (also from SuperBrightLEDs). It's a "pulse width modulation" dimmer so that there is no change in output spectrum. It's a no-brainer to hook up.

Attached is the "Mark I" I made. I've since replaced it with a safer version, which is similar but larger and with a slot to insert #1 and #2 Kodak safelight filters. With that setup I get safe times way longer than I'd ever need, and it works great for making masks with ortho films (the reason I went down this path in the first place). The dimmer makes it really flexible.

While safelights are everywhere, good ones are not, and just because something's expensive doesn't mean it's any good either.

Depends on what you mean by "a good one." All those rectangular ones take standard filters and in my experience are very safe. So is my Patterson and I presume the same design labeled Arista and the newer different shaped Patterson.

But if you mean some are not safe, true enough - like that Yankee with the white body and the two filters, one of which is not safe at least for VC. Granted it's labeled for graded but the VC filter is so un-necessarily dim it tempts one to try the graded filter.

What you will get with LEDs is, probably (I'm going to verify this with mine of course) more light while still being safe, along with longer life and less fragility. That doesn't mean the others don't work fine.

Still wondering if anyone has had any problem switching the LEDs with relay based timers. I'm going to try it anyway. If it fries them I'll eitehr go back to my regular ones until I can work out some noise suppression to isolate them more or just leave them on during exposure. I got used to that when I used my Duka regularly for B&W anyway.

 

[scheimfluger_77]

You know what's intriguing about this, is the blue and green bulbs. Should these bulb's spectrum be compatible with VC paper emulsions it's a short leap to building your own additive VC lamp house for your enlarger.

Steve

 

[Roger Cole]

I think that's been tried already, not sure how successfully.

I have an LED white light lamphouse for my D2. It works beautifully with normal VC filters so the spectrum is pretty consistent with the original PH211. It has the bonuses of almost no heat with no negative popping and very long life. I bought it from a gentleman who makes them and posted them for sale on here and the LFPF. I don't know if he's worked on the VC head idea or not.

 

[Roger Cole]

Film yes, very different.

Another reason, if you can find them with the right emission line, would be more useful RA4 safelights. You can use the conventional ones as PE has posted but they need to be VERY dim (that said, just seeing outlines is VERY useful.) My Duka on lowest setting bounced off the ceiling is safe for brief exposure for RA4 and about as bright as a conventional Kodak OC black and white, but they are no longer available new. (Which is why I don't use mine for black and white.)

The reason I am trying them is just to see if they are brighter than my regular safelights (well, one "regular" and a Jobo Maxilux which can still be found used from time to time) while being as safe. It's a fairly cheap experiment and if I don't want to keep them I can probably unload them here for less than I paid and cut the cost even more.

 

[Leigh B]

if you can find them with the right emission line, would be more useful RA4 safelights.

There's a disconnect here.

Even if you can find an LED or similar emitter that's highly monochromatic, i.e. a single spectral line...

the response curve of the film is not well-delimited, with significant sensitivity throughout the visible spectrum,
even though the sensitivity peaks are well-delineated.

With that type of film, no safelight can be completely safe.

- Leigh

 

[Roger Cole]

There's a disconnect here.

Even if you can find an LED or similar emitter that's highly monochromatic, i.e. a single spectral line...

the response curve of the film is not well-delimited, with significant sensitivity throughout the visible spectrum,
even though the sensitivity peaks are well-delineated.

With that type of film, no safelight can be completely safe.

- Leigh

There certainly is a disconnect. Who the heck is talking about film? Ok, I know the prior poster was, but I think about ortho film which certainly is safe exposed to red, if the red is narrow filtered and any other colors sufficiently low level.

I know that RA4 paper is sensitive to all colors. But I also know it's less sensitive in some places. I think, but do not know, that this corresponds to the color of the orange dye masking layer. At least that looks very close to the color of my Duka 50 sodium, which again I have tested and shown to be safe for RA4, at least for 5 minutes exposure, when set on the lowest setting and bounced off my white ceiling in my old darkroom, with my particular set up. PE has posted about using the conventional #13 I believe, dark amber filter with RA4 successfully. Very dim, but better than nothing, and safe used properly. My reference to LEDs would mean that you need a similar emission - perhaps something slightly different would work even better.

There is also this, but it's more for a flashlight (aka torch on that side of the pond) for looking into nooks and crannies, dropped items etc.

http://www.rhdesigns.co.uk/darkroom/html/safetorch.html

 

[Leigh B]

I have film on the brain. Lots of threads going on here and LFPF about film processing.

My comments apply equally to color paper. You can find spectral regions of reduced sensitivity, but not zero.

- Leigh

 

[Roger Cole]

Not zero true but low enough that a useful safelight is possible.

 

[Ken Nadvornick]

For example, quoting from a report entitled "SPECTRAL SIGNATURES OF NIGHTTIME LIGHTS":
"High and low pressure sodium vapor lamps have very little variability. Both have strong emission
lines at 819 nm. The low pressure sodium lamp has only one additional emission line of any
consequence, at 589 nm." (emphasis mine)

Hi Leigh,

Real world observations always trump theory. So I went down to my darkroom and fired up my Thomas Duplex and let it stablize. It has a reasonably low mileage tube. I removed all filters so I could see the bare bulb. Then I located my copy of The Hunt for Red October. (Appropriate for safelight testing?) I held up the DVD at an oblique angle to the bulb and observed with my own eyes the color bands generated tangentially to the recording tracks. This happened about 15 minutes ago.

In addition to the overwhelming sodium D-line I was also able to easily make out additional blue, green and red bands. These corresponded very closely in both color and relative brightness levels to the three non-sodium emission spectra documented in Brian Niece's LPS discharge tube image and graph. The blue was very deep and the faintest of the three. The red was a bit brighter, but not nearly as bright as the green. But all three were unmistakable.

I then refitted the Roscoe #19 Fire filter and looked again. As expected, the blue and green bands had disappeared, but the red was still visible. In other words, the Duplex was now converted into a truly safe light.

If you look at the transmission chart at the above Roscoe link you'll see that in addition to cutting off the shorter wavelengths the #19 also transmits only about 35% of the sodium orange light. This also appeared to correspond visually with what I was seeing.

Where do the additional emissions come from? I'm still speculating from impurities introduced inadvertently into the tube by the manufacturing process or materials, or on purpose as a consequence of the engineering required to create a commercially viable product. For example, this article describes the neon and argon Penning mixture added to LPS tubes to assist with the inital striking of the lamp.

I would strongly suggest that you try the above first-person observation for yourself.

Ken

 

[RalphLambrecht]

what in your opinion, is a proper safelight?

 

[SkipA]

Ralph, David Brown (the OP) mentioned someone using 20 cent red light bulbs that were not made for darkroom use and who subsequently found out they were not safe. So I would understand "proper safelight" in that context to be one that was engineered and intended to be a safe light for a darkroom.

In my opinion, that would include both commercially made darkroom safelights, and home made safelights (such as LED lights) that are carefully researched, built, tested, and proven to be safe.

However, I believe the OP was referring to commercially made purpose-built darkroom safelights, which are cheap and plentiful and easy to obtain, at least in much of the world. There is rarely a shortage of usable safelights on eBay, for example. The point being, why spend a lot of money to build a darkroom, then try to use something unsuitable for a safelight that wasn't designed for such use or proven to be safe?