Using a OA safelight filter in a darkroom with OC filters????

[IanG]

There are hidden issues that most safe-light tests miss and that's the adverse effects on contrast with Multigrade papers and the best filter is definitely the OC/902.

If you have some red gel you could add a couple of layers and probably convert an OA into an OC, however OC filters turn up now and again quite cheaply.

Ian

[Bill Burk]

Hey Bill,

Where did you find the spectral graphs for the safelight filters? Is there an online source? I'd sure like to take a look at them.

Best,

Doremus

Oh good, Michael R posted a good link. I was looking at Kodak Filters for Scientific and Technical Uses, CAT 152 8108, but the graphs in his link look just as good.

[callsign.BULL]

Observations on OA Safelighting:
I rig a small 5x8, white-painted bathroom with two Kodak bullet safelights with OA filters. The 15 watt, down-firing Model A is screwed into a recessed ceiling socket 5 ft from the work area and the 25 watt Model B is on a shelf, up-firing at the ceiling also 5 ft away. I contact print with ADOX Lupex (about ISO P3) and Foma Fomalux (ISO P12), both silver chloride papers. I have done fogging tests similar to Jim Jones' #9 post with both papers. At a full 32 minutes of exposure with both safelights on there was not a trace of fogging. Same results with OC filters. So, if your thing is contacting on slow, graded silver chloride papers, the OAs are good-to-go. But I find other benefits: First, the OAs' bilious greenish-yellow registers details very brightly and acutely (think of the construction workers safety vests used these days). More bang for your lumens; I'm even thinking of reducing the Model B to 15 watts to save fading the filter. Second, 5.5-inch OC filters are not easy to come by and are expensive when found, but NOS OAs are readily and cheaply found on eBay - perfect for me. I recently bought three un-opened OAs for 10 bucks apiece. Obviously inappropriate for VC or bromide papers.

[Paul Ron]

get illford data sheets here

https://www.ilfordphoto.com/technica...ographic-paper


quoted from the illford data sheet

Safelight recommendations
MULTIGRADE FB CLASSIC can be safely used with
safelights that have dark orange, dark brown or red filters.
eg ILFORD 904, ILFORD 902, Kodak OC, Kodak 1A, and
Paterson red Dome A safelight.
A 15 W bulb is recommended with safelights.
Good darkroom practices should always be adopted, by
keeping safelight exposure to a minimum and always
returning un-used paper to the original packaging.
Ideally, safelights should be positioned a minimum of
1.2m / 4ft away from the paper.
If in doubt as to whether a safelight is safe, tests should be
carried out. Refer to the technical information sheet
‘Safelighting’ for how to carry this out.
Web link to
http://www.ilfordphoto.com/applications/page.asp?n=148