henribroy
Hello everyone,
I’ve found another darkroom lamp that has an Orwo 113 glass filter on the light side. However, as the filter appears to have become unusable (streaks and inclusions) and I actually need red light for my paper, here’s my question:
Are such Orwo glass filters (a red one would be type 107) still available to buy anywhere?
Thanks in advance and best regards, Henri.
Abi
Hello Henrybroy,
Banse and Grohmann still have some Duka filters left in stock.
Best regards
Gast
Henri,
What size is the lamp? Ilford make—or used to make—filters; perhaps Mirko can get hold of some for you. There are also Kaiser filters available in 9x12 (and only in 9x12) that will fit.
Otherwise, try Banse and Grohmann, aka wephota—I won’t post a link, as it would just disappear again on its own.
Roland
henribroy
Thanks!
I've found the site.
Best regards, Henri
cfb_de
Hi Henri,
A standard piece of glass covered with two layers of "Rubylith" or "DC-fix" works quite well too.
Then there’s cheap red peel-off paint, which also works as a filter.
Or: pop in a frosted glass pane and buy a red LED spotlight from Conrad.
I’ve got the latter dangling in my bathroom light while I’m doing some Duka work. It works a treat and goes absolutely perfectly with my Vario Classic too.
Best regards,
Franz
henribroy
Hello everyone,
Thank you very much for the useful tips.
I’ve just done a veiling test with the existing green-yellow panel, and my standard paper (Fomaspeed) shows no issues. When assessing the enlargement in the developer, I find this light a definite improvement compared to the red Philips bulb.
I’ll be trying out the alternatives with my own glass pane, peel-off varnish or film for the other papers soon.
Best regards, Henri.
MirkoBoeddecker
ORWO red filters are either too light (fogged with a pale red color) or, whilst haze-resistant (107, 108), are actually intended for X-ray film and are therefore far too dark.
There are no suitable red filters from ORWO for Variokontrast papers because ORWO never actually produced such papers.
Had such a filter existed, it would have been a bestseller for years after the fall of the Berlin Wall.
So we’ll just have to make do with DIY solutions.
Best regards,
Mirko
Gast
When it comes to darkroom lamps, vague terms such as ‘red’, ‘dark red’ and the like are often used – is there an overview that specifies the respective wavelengths?
Only then can one compare whether, for example, red LEDs might actually be a viable alternative to a ‘red’ light bulb or to the Orwo filter discussed here ...
cfb_de
Do what the German Institute for Standardisation has still not managed to sort out.
Measure the filters in the UV/VIS range and publish the results. After x hours of use, take the measurement again and publish the (completely different) results.
It’s as simple as that. These cheap green attachment filters cannot be specified in terms of their transmission spectrum. And that’s particularly true because no manufacturer knows whether the customer is hanging a dim oven light or a 25W energy-saving bulb behind it.
A simple haze test costs exactly one sheet of paper and takes less than thirty minutes. And you do it exactly three times per paper type: the ‘first’, ‘only’ and ‘last’ time.
With decent LEDs, the spectrum is documented in the datasheet. Combined with the datasheets for the photo paper (which, annoyingly, are inside the box), you can almost do without the veiling test altogether. Hand the morning paper to your partner; you can simply read the two datasheets yourself. Or just do a haze test after all, if, like me, you’ve bought the cheapest LED bulbs from Conrad.
And please choose a username! Then my future replies won’t be quite so harsh. And, who knows, maybe you’ll even be welcomed and bid farewell.
This forum isn’t an automated reply machine either; here, too, you’re dealing with people.
Wolfgg
Well, I can confirm that too: in the long run, LEDs are the best option. Just a few connected in series and placed around the lab; if you want a universal setup, three sets of red, yellow and green LEDs each will do the job. Once, for RA4 (colour negative), I simply took a few yellow LEDs out of a drawer without checking the spectrum in detail and set the brightness to just the right level; the paper remained completely unimpressed. It still works today. And the best thing is: you don’t have to worry about it again until at least 300,000 operating hours have passed. But not because the spectrum has changed, but because the brightness might have dropped to 70% by then. How many ‘lab years’ of a hobbyist would that be?
henrydroy: “Assessing the enlargement in the developer” sounds like the wrong approach. Apart from a few special processes such as lithography, you don’t need to be able to assess anything in the developer; instead, you must conduct full development of the film, i.e. develop it according to time. Inexperienced photographers should even start by developing with the emulsion side down, so that overexposure is not “compensated for” by underexposure under any circumstances.
Regards, Wolfgang
henribroy
Hello Wolfgang,
I develop by timing. However, a visual check is important to me because I want to be able to tell, whilst the image is still developing on the paper, whether my exposure was more or less correct. This is particularly true for test strips.
20x30 or larger on baryta paper only works for me when turned upside down, as the warping of the paper means that this is the only way to ensure even wetting of the paper.
A green light in the darkroom suits me in that, when I’m doing a final check of the sharpness on the enlarger before I dim the light, I feel I have a better view of the projected negative.
I don’t think the idea of building a Duka lamp with LEDs is a bad one.
Regards, Henri.
