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  #11  
Old 31st May 2011, 07:31 PM
Mike O'Pray Mike O'Pray is offline
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Thanks Bob. My Duka's slots are at 90 degrees to the lamp so the top of the slots form a natural barrier to the light and is on the "darker" side of the room i.e. opposite side from the DUKA. The DUKA beam for want of a better word runs down the opposite side of the room.

I'll keep my eye open for signs of safelight fogging

Mike
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  #12  
Old 1st June 2011, 12:10 PM
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Roy_H Roy_H is offline
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I have a brand new, unused Kodak No.13 safelight filter (dark amber, for colour negative papers and panchromatic b&w papers).

It's a 5.25" circular, designed for Kodak Beehive safelights.

I'm unlikely to ever use it, so if you want to give it a try please PM me.
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  #13  
Old 7th June 2011, 12:27 PM
Mike O'Pray Mike O'Pray is offline
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A bit of a follow-up on my part. I tried to do a test for the DUKA using what I recall to be the previous setting I had used for RA4 which was 10. This is amazingly bright and probably accords with Dave's "read newsprint" level although that might be stretching things a bit but certainly a very comfortable level.

I hadn't seen any fogging previously even when I used to cut 10x8 to make 2x 5x8s then place in easel and finally into the drum or none that I recognised. However I now recall that all my prints were borderless and it is just possible that any fogging was disguised. No white borders to check.

I tried a crude test last night at a level of 10 and cyan fog was apparent in a matter of a very short time less than one minute. Either I need to be lightning fast at paper removal, placing in easel, exposing and placing in Nova slot or I need to reduce the level to what I think will be just about a manageable but not comfortable level.

Dave, what test did you apply to get to your 5 mins level? Based on last night, I'd give my right arm for 5 mins safety. 2 mins or even one might do.

It kind of suggests that cutting down 10x8 to say 5x7( two cuts needed) is now a no-no unless done in total darkness and these days 5x7 RA4 cut paper is unobtainable.

Thanks

Mike - somewhat demoralised
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  #14  
Old 7th June 2011, 02:02 PM
Dave miller Dave miller is offline
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Firstly if you use a paper trimmer with a card guide stuck on it then I imagine cutting sheets of paper could be done in a very low light level.
Secondly if you look at the picture of my enlarger at the bottom of my Darkroom Article you will see the position of my 15w Ilford 902 safelight (actually I now have two, another on the right-hand side) is shielded from the baseboard by a screen, so effectively the safelight hitting the baseboard is reflected light only. When I used a DUKA sodium light in my old darkroom it occupied a similar position, but in a room with distinctly off-white walls and brown wood doors.
As for testing I placed a row of 10 pennies on a sheet of 10x8 on the baseboard and then removed one per minute before processing the paper, to see at which point fogging became apparent, not the best test as I now realise. This was for EP2 and RA4 processes, for Ilfochrome I worked in complete darkness up to the point when the paper was curled up and sealed in a processing drum. With my existing set-up (for B&W) my safelights are connected through the RH timer so that they switch off during the exposure time, but that’s just my preference.
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  #15  
Old 7th June 2011, 03:00 PM
Mike O'Pray Mike O'Pray is offline
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Thanks Dave. My set-up is different as I can't have my enlarger in the middle like yours such that if the DUKA was where your 902 is then the light has to go down to the end and be reflected back so it has a long way to travel and might account for greater safety. I'll need to give it a bit more thought but I may be stuck with reducing the DUKA light level.

Mike
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  #16  
Old 9th June 2011, 09:20 PM
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Roger Cole Roger Cole is offline
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Quote:
Originally Posted by Mike O'Pray View Post
Keep an eye open for a DUKA 10 or 50 on e-bay. These are effectively the same lamp but the 10 is the earlier model. A good light but the wave length used makes the paper "blind" to the light

They fetch a fraction of what there were when new. Make sure you get the seller to confirm the lamp lights. The replacement sodium bulb cost a fortune. If it goes it is cheaper to buy another DUKA

Mike
My understanding from looking for them and talking with Bob Salomon of Marflex who used to import them is that the lamps are now unavailable new anywhere at any price.

I have a Duka 50, which I used to use for both B&W and color. I'll be reserving the lamp life for color from now on.

Quote:
Originally Posted by RH Designs View Post
The Duka 50 sodium safelight's about the only one that can be truly regarded as "safe" but even then it's touch and go because RA4 materials are so fast. If you can work in darkness I suggest you do, unless you can find a Duka 50 but even one of those will fog RA4 sooner or later. The right sort of yellow LED is OK but you should never shine it directly at the paper, and ours has a momentary action switch for a good reason! LEDs have a wider spectrum than the sodium lamps used in the Duka.
In the late 90s I set my Duke 50 on the lowest level opening and had it mounted near the ceiling and reflecting off it. The ceiling was white. Even so, at this lowest setting it was about as bright as a conventional safelight with a Kodak OC filter. I even used it for Ilfochrome with no issues at all. I found I couldn't use it at full brightness with VC papers either, but on about half it was safe.

However, I've heard from very reputable people that the conventional dark amber color safelight filter IS safe with modern RA4 papers, if used carefully. It's amazing what a low level of illumination is still useful. Even just being able to see shapes in silhouette is much better than total darkness.

One additional point is that, as Dave said, just placing coins or other opaque objects onto paper and exposing to the safelight is not the best safelight test. Photo emulsions have a threshold below which they do not respond, but once that threshold is broken by your image exposure, a far smaller additional exposure will result in noticeable fogging. To really test your safelight, work in total darkness to determine an exposure under your enlarger that yields a light gray, say about zone VII or so in black and white. In color I'd also try to adjust for a neutral color balance. Then, still in total darkness, give a small sheet of paper this exposure (no negative in the carrier) then place your coins on it and turn on your safelight. It can be really surprising how un-safe a light you used to think was safe can really be.
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  #17  
Old 9th June 2011, 10:36 PM
Mike O'Pray Mike O'Pray is offline
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Thanks Roger. There is little doubt that based on my experience of the last few evenings when trying to calibrate a Colorstar 3000 analyser and generally getting into colour printing for the first time in several years I have had to conclude that what I thought was a safe level of lighting clearly isn't.

As I hadn't used my DUKA since I last did colour then I am pretty sure that I hadn't altered the setting which was still on 10 when I used the DUKA again. This is pretty bright and on a par with my B&W Ilford 902 safelight. It clearly wasn't safe for the time needed for comfortable processing using a Nova.

The strange thing is that my borderless prints of a few years ago looked OK at that light level. It may have been that a more experienced printer would see fogging in the prints and of course as they were borderless there were no white borders where fogging might have shown up more easily.

The other explanation is that I was using Jobo drums and the time required to simply remove the paper from the safe, place under the easel, expose and place into the darkness of the drum was only maybe 10-15 seconds which might be safe at a setting of 10.

Anyway I think I was able to lower the safelight level to a "safe" level last night. As you said it was much gloomier than what I am used to with the Ilford 902 and B&W but perfectly manageable.

I'll miss the lovely glow of the DUKA at setting 10 but that's the price to be paid for RA4 and using the Nova.


Mike
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  #18  
Old 2nd May 2021, 09:11 AM
John King John King is offline
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An old thread, but here goes. I would be lost without my DUKA (also sold at some time under the name of 'Kaiser').

If you have not seen one the light output is variable by a moveable internal shutter with printed graduation on the outside. I have mine set at 10 but full output is at 50. It is fastened to the wall and the head angled up at the matt white ceiling and not in direct view of the paper. The highly diffused light has about 8-10 feet to travel before it hits the paper. As I work in in the shadow of the light the exposure is much less than you would expect. A test exposure on both Kodak and Fuji paper shows no change after 40 seconds exposure. This is a bit longer than a normal 12x16 sheet is usually exposed with a 35mm neg.

I also use it for B&W and can turn the light output up to 50. Even at full output it will not fog a piece of MG5 with over 2 mins of exposure.

Replacement bulbs are rarer than hens teeth and when/if you find one it will cost twice the price of a replacement 2nd had complete light.

Last edited by John King; 2nd May 2021 at 09:14 AM.
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  #19  
Old 2nd May 2021, 11:38 AM
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Martin Aislabie Martin Aislabie is offline
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Heiland do a new LED colour safelight - https://heilandelectronic.de/safelight_co/lang:en

I have the B&W version and they are very good.

I run mine through my RH Stopclock - so it is off when the enlarger is on.

Martin
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  #20  
Old 2nd May 2021, 12:23 PM
Terry S Terry S is online now
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Quote:
Originally Posted by Martin Aislabie View Post
Heiland do a new LED colour safelight - https://heilandelectronic.de/safelight_co/lang:en

Martin
I don't do colour work, but here's a thought / suggestion...

Reading the specs on the page link above, the colour tube is stated as being ' 590nm'.

Typing this into ebay UK, it came up with a number of items, but one was a standard light bulb, in an E12 base, that says that it is in the 590nm spectrum.

Especially if one could get one in the UK and i.e. cheaper, would this be worth a punt? It's an led bulb btw, which are becoming popular on sites like this, for b/w safe lighting, so maybe this one could be used for colour work?:

https://www.ebay.co.uk/itm/111809572...UAAOSwAvJXBsxm

Terry S
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