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Foma papers Safelight

Auroraua

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I have a question regarding o some of the Foma papers and safelight. I want to buy fiber with variable contrast paper and accordingly they have the information below.
I am concerned what will happen in my darkroom, I thought red is the strongest color so should not be affected, but I feel confused.
Am I safe buying this paper with red light in the darkroom?
I though red is stronger than orange, or yellow.

Info from Foma:
FOMABROM VARIANT III is an ortochromatically sensitized photographic paper.
Therefore, a suitable safelighting differing from that for conventional photographic papers should be used. Dark-red safelight filters for orthochromatic materials, e.g. Kodak GBX-2, Ilford 906, Agfa R1, Osram Duka 50, etc. in connection with a 15 Watt lamp are fully suitable. More comfortable and user friendlier light sources may be used with orange LED diodes, eventually orange filters however with a safe wave length band pass over 610 nm. Because of its high speed, FOMABROM VARIANT III should be exposed to this safelighting only for a time rerequisite to handling.
Exposure
FOMABROM VARIANT III can be exposed in all types of enlargers and printers equipped with tungsten or tungsten halogen lamps. Particularly suitable are devices with a special colour mixing head for multi-contrast papers. Other erlargers can also be used, but separate correction filters should be inserted during exposure.
FOMABROM VARIANT IV 123 is processed at indirect safety illumination with wavelength of 590 nm and higher, corresponding colour of safety illumination is amber or orange. As to its high sensitivity the processed material has to be exposed to such illumination only for the time necessary for its processing. Length of exposure and a distance of the processed material from the illumination source should be tested.
FOMABROM is routinely processed at indirect safety illumination with wavelength of 575 nm and higher, corresponding colour of safety illumination is yellow, yellow-green, amber or orange colours are recommended. Regarding its high sensitivity the processed material has to be exposed to such illumination only for the time necessary for its processing. Length of exposure and a distance of the processed material from the illumination source should be tested. Direct light has to be diffused by inserting mat glass.
 
The safelight I use is the Ilford 902/Kodak OC type with all VC papers that includes Foma. My main 2 safelights are actually Paterson with the amber VC filter domes. I also have a Kodak Beehive with a 10B which is a darker amber so still safe.

It can be worth using a dimmer switch with safelights that way you can turn them down if needed. Some red filters can affect VC papers, while not fogging them they can prevent you achieving a full range of contrast grades.

Ian
 
Ian Grant said:
The safelight I use is the Ilford 902/Kodak OC type with all VC papers that includes Foma.

Ian
Click to expand...

Interesting and useful info, Ian. I was under the impression that the 902 which I have might not be safe with Foma so have avoided it.

Thanks

pentaxuser
 
pentaxuser said:
Interesting and useful info, Ian. I was under the impression that the 902 which I have might not be safe with Foma so have avoided it.

Thanks

pentaxuser
Click to expand...

cowanw said:
Red is 620 and up and so more than either the 575,590 or 610 and up in the literature. Red is safe, but test; not all reds are red!
Click to expand...


With all safelights it's about the distance from the paper and the intensity of the light. The assumption that a Red safelight might be safer is countered by the HERSCHEL EFFECT : a partial destruction of the latent image in photography by action of long wave radiation which is either red or infra-red. This has a more noticeable effect with VC papers than graded

Some years ago there were a few reports of poor contrast range with VC paper, people couldn't achieve the higher contrast grades with the Paterson dome red filter. Paterson introduced their VC brown.Amber filter to counter this. In 1986 I'd moved from a large darkroom with red safelights on a dimmer which I always used as low as practical to a small darkroom my old safelights weren't practical (too large) so I was using a Paterson red safelight and I noticed that I couldn't get much post Grade 3.5 with Ilford Multigrade FB, changing to the VC dome solved that.

Ian
 

Fascinating!
Maybe there is a reason to dial up the cyan in a colour head with VC paper.
Although the literature seems to suggest 500 watts of light to achieve the effect and the references are originally for blue sensitive plates and subsequently for film, but there is not a lot of web based information on this.
 
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Dialing in the Cyan filter just acts as an ND filter, so no benefit unless your exposure times are to short..

LP Clerc in one of a few references to the Herschel effect states: This phenomenon is often better observed by long exposure and weak illumination than by short exposure to a light which is very intense. The emulsions that make up VC papers are spectrally sensitized to blue & green light.

Ian
 

The simple answer is to test for your safelight's safety. No literature from a manufacturer can be relied on because they can't test their product in YOUR darkroom.

I use Fomabrom Variant III all of the time without issue. However, I am used to working in relatively dim darkrooms. My safelight (in a small darkroom) is an Ilford brown coloured one that is 3m from the enlarger and developer. This I have tested to be safe up to 12 minutes (more than enough for me). I also have an old GDR deep red safelight near to the developer dish which is only on when the paper goes into the developer and when I take it out (the rest of the 3 minutes it is off). This red safelight is 'safe' up to 2 minutes but certainly not more.

Bests,

David.
www.dsallen.de
 

Ian,

You've piqued my curiosity. I did a couple of hours of searching, but came up with nothing on the Herschel Effect and variable-contrast papers. There is an article or two out there, but unavailable without expensive subscription to an optics journal.

So, at the risk of hijacking the thread, I'd love to know more about how red safelights might reduce contrast in VC papers. Do you have any resources you can summarize here or direct me to.

Thanks in advance,

Doremus
 

I don't know where to look now Doremus, I never saw specific articles about it but there were comments in magazines at the time that some people weren't able to achieve the higher Contrast grades with Mulitigrade papers and Red/Orange safelights and that was my experience when I moved to a small darkroom. Paterson released their VC Amber/Brown safelight dome filter to overcome this, I think when they released the VC filter dome they referred to possible latent image bleaching with the orange/red safelights which is another term for the Herschel effect. In the UK Paterson had the lion share of the market for home darkroom equipment like safelights in the 70's & 80's.

I had (still have) 4 or 5 of the older style Paterson Safelights and remember being annoyed as I had to buy a new dome type (current) Paterson safelight with it's red/orange dome and then a separate VC amber dome which was only sold on its own,

If you read "LP Clerc, Photography - The Theory and Practice" 2nd Edition 1937, he mentions the Herschell effect numerous times, he says in a foot-note "Various experiments have led this effect to be regarded as a return to the halide state of the silver liberated at the first exposure to light".

At it's extreme the Herschel effect can be used to produce direct Positives from a previously fogged film.

This paragraph from Kodak Patents is relevant and gives the best reference: Herschel effect The Herschel effect dates back to 1839 and is a phenomenon quite well known in the photographic field. A fairly comprehensive discussion of the effect is given on pages 277-289 of The Theory of the Photographic Process, by C. E. Kenneth Mees, published by the Mac millan Company, New York, 1942. As pointed out in that text, the degree of sensitivity to the Herschel effect varies somewhat from one photographic material to the next but a large number of materials are known which show the Herschel effect.

Mees says: If an emulsion which has been exposed to blue light is subsequently exposed to long-wave radiation before it is developed, some of the effect of the original exposure is erased. In other words, the red light is capable of destroying to some extent the latent image formed by blue light.

With Graded materials any effects of the Herscel effect would be negated by a slight additional exposure to compensate, you wouldn't even realise it might be occurring. However with a VC paper containing a mix of 2 or 3 emulsions each with slightly different Blue/Green spectral sensitivity and speed the component emulsions would behave differently to the Hershel effect and this would skew the contrast grade. It appears that it's most Blue sensitive component that controls the high contrast that's affected most.

Ian
 
Ian Grant said:
Dialing in the Cyan filter just acts as an ND filter, so no benefit unless your exposure times are to short..

Ian
Click to expand...

My comment was to the effect that red light at the time of exposure might stimulate the Herschel effect.
Notwithstanding that, red traditionally does not play a role in paper development, so, actually, dialing in cyan is really a minus red and has no effect as a ND filter.
As an aside, such an obscure notation as a namesake, for a very large figure in photography.
 
Doremus, this is what "Positive Materials" part of a series of books that make up a later updated 3rd 1970/1 edition of LP Clerc "Photography - Theory and Practice" says:

761. Herschel Efect. The Herschel Effect which is very large on some slow papers, may be used to lower the contrast of prints from hard negatives; after exposure to White light a prolonged exposure is given to red light, the effect being greatest in the most strongly exposed parts of the print (P. Strauss, I928).

Ian
 
Ian,

Thank you very, very much for the time and trouble to research and respond. I appreciate it greatly.

This gives me a bit to think about. In my last darkroom, with two 8x10 Kodak safelights with red filters, I often had problems getting a lot of contrast out of the occasional flat negative, even with all the magenta dialed in on my color head.

At present I'm in Europe and have a project ahead of me building and installing my darkroom in my new house in Oregon this summer. After it's up and running, however, I've got a few tests to do! I'll compare a prints made with all the magenta filtration and then allowed to sit under red safelight for various times. As a control, I'll make a print with a #47 blue filter and processed in the dark. That should tell the tale about Herschel and his Effect. I wonder if this is one of those widespread but unrecognized phenomena or really only negligible...

Maybe I'll end up with another tool to fight high-contrast prints on graded paper as well

Best,

Doremus
 
Thanks. I have bought a small packet of Variant IV so I will do a check, if it works, I will buy more. The safelights were there, so I am not sure which ones they are, but they are Red
What is the scale of safelights is amber stronger than orange and red stronger than orange or amber.
 
The scale is really from Yellow through Orange to Red. The OC/902 filter is described as Light Amber really it's yellowish brown. The darker amber filters can be used with Panchromatic papers (like Panalure - no longer made). So on that basis the scale is really Yellow, Orange, Red, Amber.

Safelight filters do fade some more than others which could be why some get fogging with OC lights. Red lights are fine, the issue discussed above is extreme, small darkrooms, safelight far too close to the paper.

Ian
 
I use Fomabrom Variant IV with regular cheap red LED bulbs (with a standard G9 mount fitting to any halogen lamp) without any problem. I have asked the bulb manufacturer for the characteristics curve of the bulb to make sure that the peak is behind ~610nm. Then, in the darkroom, I have made a 5-6min test and everything was fine. This solution was much cheaper than a dedicated darkroom safelight.
 

Gracjan, did you do a test that involved paper pre-exposure, like the Kodak "How safe is your safelight" test? Or did you just expose a sheet of paper for 5-6 minutes under the safelight, masking a section off? If the former, then I'd be impressed with your LEDs, as in my test of several brands of LEDs I have found them not to be safe at these times: they do not fog paper visibly, however they pre-expose it enough to seriously affect contrast. To anyone who has the time and willingness, I strongly recommend the Kodak safelight test: fighting contrast issues with wasted time and paper later on is not worth a minor saving on the safelight.
 
gracjan said:
No, I did the "regular" test. Interesting point; although I haven't noticed anything wrong with the contrast, I will try to make the test in the proper way. Thanks for info.
Click to expand...

Good luck with it, I hope you don't need to make much of a change to your LEDs, but if you do, it is usually possible to add red filtration, such as with Lee lighting gels, easily found in Europe.
 
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