Old glass darkroom filters OK (?)

[ColinRH]

I'm interested in development by inspection and need to source a dk green safelight filter. I'm not aware of any currently available safelights but can get dk green filters online from the usual place.

Will old glass filters of the Ilford, Wratten and Kodak type lose their filtration ability over time?

 

[AgX]

True glass filters will not change. But there may be glass filters that are actually a sandwich of two glass plates and a dyed gelatin foil. That dye might have changed under radiation.

 

[jim10219]

What kind of film are you developing? You can still buy Thomas Duplex Super Safelight filters for ortho films. They only work with the Thomas Duplex Super Safelights, as you need the low pressure sodium lights for them to work properly. They also don’t last forever, as they’re the kind with the gelatin sandwiched between two planes of glass.

If you’re wanting to do panchromatic B&W films, you might consider getting some night vision goggles. They might even work for color films, I don’t know. But they won’t work for IR sensitive films, as they produce IR light.

 

[ColinRH]

I use FP4+. I would only use what I assume to be fully dyed glass filters from Kodak, Ilford or Wratten.

 

[Ian Grant]

You can't have Kodak or Wratten

Kodak bought Wratten and Wainwright in 1912 as part of the deal to employ CEK Mees to set up and head Kodak Research. So unless very old the safe-light filters are Kodak Wratten. The Dark Green Wratten 3, or Ilford 907, filter should be OK.

Ian

 

[tezzasmall]

I've read about a lot of people using small LED coloured lights in the darkroom for black and white = I now use one too = it's the only one I really need now, as they are so much brighter than the Paterson etc. safelights.

So, I just thought to ask, 'Has anyone tried any of the coloured led small coloured lights for development by inspection of any film?'

Terry S

 

[Ian Grant]

Terry, I have a Wratten 3 dark green filter for a Kodak Beehive safe-light and it really is a very low level of light, I'm sure LEDs could be used but they would need a filter screen to cut their output to a minimum.

Another option may be a Wratten 10/Iford 908 Dark Amber safe-light these are listed as for use with some Panchromatic materials and also Ektacolor papers, there was also a 10H tweaked for a specific version of Ektacolor, in practice very little difference, I have both. Often these filters are designed for indirect use where the safe-light is aimed at the ceiling further reducing possible fogging exposure.

Ian

 

[Maris]

I've tried and failed to do development of panchromatic film by inspection under a very dim green light. "Development by inspection" is a misnomer in my experience. What does work is to develop under absolute darkness for most of the expected development time and then take a quick glimpse at the film using the green light. Once a film has traversed most of the development time its light sensitivity is rather reduced so that quick glimpse won't harm it. If it needs more development then continue in the dark and glimpse again....
The other problem is that a developed but unfixed negative under dark green light looks nothing much like a finished negative on a light-box. Learning to correlate these two different appearances means practice practice and many pieces of film. I'm not sure what problem "development by inspection" is intended to solve that a properly calibrated time and temperature routine doesn't make easy.