Discussion in 'Darkroom Equipment' started by Dave Dawson, Aug 1, 2009.
Anyone use a safelight for colour paper....If so what which one do you recommend?
It's best no safelight as the paper is extremely light sensitive. Sometimes even an odd LED on a haeter or timer is enough to cause problems.
I have a very small amber LED "safelight" from Nova that illuminates (dimly) the stopclock, but that is the only light used when printing RA4. The dev trays are kept several feet away from the stopclock.
But then I haven't done any safelight tests, so I may have low level fogging..
As Paul says something like that is just acceptable, I have something that I used for Cibachromes in the 70's, its output is so low it throws no circle of light and is just enough for watching a clock type timer for developing prints.
I have a Philips enlarger timer that will fog colour paper because the dials are illuminated, so they need to be shielded.A friend had a constant slight green cast he couldn't get rid of and he tried everything, he just couldn't find a reason, turned out he used one of those early digital watches with the red diodes or whatever they were to time development
The best safe light for color paper is no safe light.
I was in a darkroom once that had a safelight for color paper. It worked well in that it didn't fog the paper. Unfortunately, it was so dim it really didn't help. If you develop in tubes there is no need at all for a saflight, but even if you use trays it's easy to get used to working in the dark.
I thought you could use a low-pressure sodium lamp, because RA4 paper had a sensitivity notch in it? That's what I heard anyway. Seems like you could use a certain kind of LED if that's the case.
I use 2 Wratten 13 safelights pointed away from the process and handling areas at the ceiling. Each is powered by a 5 - 7 watt bulb in a beehive safelight housing.
They are safe for use if you are not directly in the beam of the lamp for any time at all, and after hours in the darkroom can give a surprising amount of illumination.
Endura paper is built to have a "hole" in the sensitivity at the spot where the WR13 passes light. This minimizes the potential for fogging. I cannot speak for Fuji paper.
Back in the 70's I worked at a Kodak plant in Holland.
In the spooling-up room for dubble 8 and Super 8 Kodachrome they had a verrrrrry dim amber safe-light, just enough to see what the machine was doing and where to keep your fingers away from.
You needed about 10 minutes for your eye's to adjust.
So amber is posible, but DIMM it !
If you have a LED rated for 20 mA try it fist at 1 mA with a peace of scrap/test paper and make shure that you can dimm the LED even further......
A safe light in your color-dark-room is just there for orientation, nothing more.
Using my amber LED safelight I can have it shaded so I can just about avoid bumping into the furniture and just make out the outline of the trays in my sink. Any more than that and I risk fogging. This is with Crystal Archive - I just recently got some Endura but have not tested it yet. A sodium lamp has a narrower bandwidth and thus may be a better bet.
The spec for Crystal Archive paper shows a dip in sensitivity between approx 580nm and 610nm but I've no idea how that compares in terms of width and depth to Endura's notch.
Little or no light for colour.
I use the DUKA 10.It's a sodium light and gives very good and safe light and doesn't fog either Fuji or Kodak paper as far as I could tell. That and the DUKA 50( the slightly later version) appear on e-bay from time to time and last time I looked Secondhand Darkoom Supplies had one for a reasonable price.
Sorry perhaps I didn't expain my future working conditions............Paper out of box, onto easel, exposure, into drum.
Than what do you need a safelight for ?????
I suppose just orintation...(do you make a cup of tea with your eyes shut?) here we go......Another 20 posts of the vertues.
But all suggestions appreciated.
So why are 'colour safelights' made?
Some print RA4 in trays. A safelight would be convenient, wouldn't it?
Kodak specifically designed the sensitivity of their color paper for use with a safelight. Actually, there were two. The earlier safelight was used with a slower version of color paper, and the current WR13 is used for the current paper. So, the safelight was designed to work with the paper and vice versa. The safelight is intended for just that, safety. In the dark, one can become disoriented and the safelight helps one maintain orientation towards equipment.
There is also a dark green safelight that can be used with many panchromatic films. It is called "Min Pan" and exists in the Kodak safelight dataguide.
The Min Pan safelight is much less "safe" with film due to the high speed and various sensitivities encountered in the field and so its use has declined since introduction, but is still used by Kodak for many purposes. However, it should be rememmbered that current color paper has an ISO rating near 100 for the blue sensitive layer and near 25 for the red sensitive layer.
How come dark green? Is the human eye most sensitive at that wavelength, assuming that it is mainly used for development by inspection?
Thanks in advance.
At one time, there was a small dip in the spectral sensitivity of Kodak films that fit this region of the spectrum well for use of a safelight just as there is now a window in the sensitivity of color paper. Not all mfgrs had or have the window in film, but Kodak has it in paper and keeps the safelight in mind. For film it is a long gone issue.
I suppose that the eye, having max sensitivity in that region does not hurt.
I have a Kaiser Duka 50 which I no longer use and would like to sell...I ve only used it in a B&W darkroom but don't have a darkroom now. It has red and white filters and the light level can be adjusted. The light it gives out is pretty dim so it needs to be put where you most want the light.
Hi Ann, Does it have a spare bulb as they are expensive I believe?
Dave The bulbs are expensive. I never use my DUKA for B&W in order to extend its life. The sodium lamp will last a long time but if it goes then finding the right replacement lamp seems to be difficult and a new one if you can find one is more expensive that buying another secondhand DUKA
I suppose one person's dim is another's quite bright but I can see well enough to cut paper with mine. The light goes from 0(almost non existent light) to 25 which is very bright i.e. ability to read print. I have mine set at 5 but if its out of box, under easel and expose I suspect that a higher setting in the illumination would be possible as this is only a matter of seconds plus into the drum and lid on.
I have never tried the safelight test but you could and increse the illumination until you get to the point where it becomes unsafe for the time you have the paper out of the box but not being exposed by the enlarger.
I have a Jobo LED with a rotating filter on it numbered 1,2,and 3.
If I recall correctly, one setting was B&W (OC), one was for color (Ektalure) and the third I don't remember, it looks similar to the one I think is OC.
Recently, a friend gave me his (newer version?) and its rotating filter is labled B&W, Kodak, and Agfa.
Does anyone know if the color filter is the same as the new materails from Kodak?
Interestingly, the two units color do not appear the same, except for the one I am sure is for B&W (OC).
Any info would be appreciated.
This is no more difficult (or disorienting) than loading film holders or bulk loading 35mm. I've done all of these in total darkness, without encountering boiling water ...
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