Wratten 10H safelight for RA4 printing?

[Andy M]

Evening All

I have a Wratten 10H Safelight - Its a sort of low level brown colour with a regular 15 watt tungsten pigmy bulb in my Beehive safelight.

My query Is this suitable for colour RA4 printing with Fuji Crystal Archive Paper?

Do any of you diehard colour gurus know of it? Or have used it for such purposes?

I'm returning to colour print after nearly twenty years so my memory is vague, but I think I remember using dull yellow lights in the RA4 darkroom at college?

Any help greatly appreciated.

Andy M

 

[Sirius Glass]

The answer is "No". Color paper, RA4, is light sensitive to the complete visual range of light and must be handled in total darkness.

 

[MattKing]

Actually...

Both the Kodak Safelight filter 10 (dark amber) and the Kodak Safelight filter 13 (amber) are designed to be used with colour photographic paper.

See here: http://www.kodak.com/global/en/professional/support/techPubs/ti0845/ti0845.pdf

They should be used only for brief periods of time, and are very, very dim.

I expect that the Wratten 10H designation is the same as the 10 designation.

This is from the data sheet for Kodak Professional Endura Premier Paper:

"DARKROOM RECOMMENDATIONS Handle unprocessed paper in total darkness. Be sure that your darkroom is lighttight. Eliminate stray light from timers, LEDs, etc. Note: Using a safelight will affect your results. If absolutely necessary, you can use a safelight equipped with a KODAK 13 Safelight Filter (amber) with a 7 1/2-watt bulb. Keep the safelight at least 1.2 metres (4 feet) from the paper. Keep safelight exposure as short as possible. Run tests to determine that safelight use gives acceptable results for your application."

If you look at the graphs in the first data sheet, you will note the tiny notches of emission for each of #10 and #13 filters.

My guess is that the #13 is newer, and the paper has only been tested with it.

Photo Engineer uses a safelight when he prints colour.

 

[Wayne]

I used a 13 last night with crystal archive. It's the first time I've used either. I used a 15 watt bulb and didn't do any testing but didn't see anything hinting of fog. It was brighter than I had hoped or expected. I had the light on the whole time, about 5 feet from my sink. I didn't have a light near my enlarger which is in another room, so exposure was limited to ~2.25 minutes before the prints hit the blix tray.

 

[Andy M]

Thanks all for your replies and info - I would say that the !0 h I have is a very dark amber - So will go with that - I only use light for lining up paper and process in darkness, so should be fine.

Thanks for confirming this Matt and Wayne - Much appreciated

Andy M

 

[Wayne]

before you go ahead, I'd want to find out what the "H" stands for. I've not seen that extra letter, just the Wratten "10". Maybe PE knows?

 

[Ken Edwards]

The #10 filter has its peak emission at a longer wavelength than the #13 filter. Because the newer color papers from Kodak have a higher red sensitivity than the ones made prior to about 1978, the peak wavelength needed to be moved to a shorter wavelength, where the paper's red sensitivity is less. Also, the green sensitivity range in the newer paper covers a narrower portion of the green spectrum, so that there is a very distinct sensitivity gap centered at about 580nm to 590nm. Also the apparent brightness of 580nm is greater than at the 600nm from the #10 filter.

One more important thing to consider about safelights, in general, is that, at exposure levels less than what it would take to fog the paper, it is possible for the highlight areas in a picture to pick up a little density, flattening and possibly coloring the highlights, subtly. So, this should be checked, when experimenting with a new safelight / paper combination, to be absolutely certain of exposure time and distance from the light that would be truly safe for your work.

 

[bdial]

See this thread re: the 10H filter; (there was a url link here which no longer exists)

 

[BMbikerider]

I don't know this particular safelight, but use a DUKA safelight which has a Sodium lamp. These lamps have a part in the visible spectrum to which RA4 is 'blind'. However, even this has to be turned down to a low setting or it WILL fog FUJI paper. I, by preference use Kodak RA4 paper from a roll in a home made light-tight dispenser and this paper has a much lower speed than FUJI (At least 2 stops) and can use the DUKA at about 1/3 of full brightness.

 

[Ian Grant]

As I discovered (in the thread Bdial has linked to) from a 1960 Kodak Ltd Professional Catalogue the 10H was more specifically targeted at use with the Ektacolor paper of the time than the 10.

I use a very strange filter sold by Aeroprint in the 1970'swho made a sort of foam spray kit for processing Cibachrome, I can't see it arouns at the moment but I think it was made by DJ Photographics? Products, it's a small fluorescing panel with a safelight filter designed for colour printing. I use it indirectly to just illuminate my timer. It's so weak all I can see is the timer a few inches away and just make out the rough shape and position on my Nova slot processor.

Next time I colour print I'll test the Kodak Beehive safe-light with it's 10H filter and compared it to what I've been using. It's worth adding that it's very much lower intensity than the Kaiser Doku safe-light and when I say indirect lighting I mean the safelight is pointing away from the enlarge & Nova slot processor and the wall behind them towards the far wall in the darkroom.

Ian

 

[Ian Grant]

Further to what Matt King wrote about the Wratten 10 the Ilford colour printing filter is a 908 and this is what they say:

Ilford 908 Dark Green All panchromatic materials, colour papers and ILFOCHROME. Although designed for the maximum possible efficiency, this safelight must be used with extreme care. Fast panchromatic materials must not be exposed to direct light from this filter for any appreciable length of time.

The Wratten 13 safelight filter is lighter than the 10 & 10H and is designed for very slow Panchromatic and Colour materials, the Ilford equivalent was a 907. So the 10H is a safer option compared to the 13.

Ian

 

[Ken Edwards]

Relative to Ian's remark, visual dimness is not necessarily an indicator of safety with a specific product. The spectral sensitivity of the product has to be considered. Relative to BMBikerider's comment, his safelight works, because its wavelength agrees nicely with the #13 filter. The sodium vapor lamp produces monochromatic light at 589nm, which is also the central wavelength of the #13 filter.

 

[Ian Grant]

Relative to Ian's remark, visual dimness is not necessarily an indicator of safety with a specific product. The spectral sensitivity of the product has to be considered.

It is when comparing two filters with essentially similar spectral responses but with different densities. A good example is the 6B and the 6BB, the 6B is for direct safe-lighting with Blue sensitive X-ray film, the 6BB is much lighter so brighter and for indirect lighting with the same X-ray film.

I was talking about visual dimness though with a safe-light used indirectly which is safe for direct use so the degree in terms of being "safe" is substantially increased bt a huge factor. Ilford safe-lighting in their paper cutting and packaging area is probably 902 filters but the lamps are under run and way below the typical normal home or commercial darkroom brightness.

So provided you have a suitable filter then greater visual dimness is also improving the safety margin by a huge factor.

Ian

 

[FujiLove]

I use a Jobo Maxilux color safelight when I print RA4 with Fuji Crystal Archive paper. It's not bright like a B&W safelight, but plenty enough to work with. I use a foot switch to minimise exposure, but I've never had any problems with fogging even when I've made a mess of something and end up exposing the paper to twice the amount of light.

The need for complete darkness for RA4 is a myth.

 

[pentaxuser]

The need for complete darkness for RA4 is a myth.

Yes but of all the myths here on APUG it must rank close to number one for longevity. I don't think I have ever seen a thread on RA4 and safelighting in my 12 years here on APUG that doesn't produce the categorical statement that RA4 must be done in total darkness.

pentaxuser

 

[Wayne]

Yes but of all the myths here on APUG it must rank close to number one for longevity. I don't think I have ever seen a thread on RA4 and safelighting in my 12 years here on APUG that doesn't produce the categorical statement that RA4 must be done in total darkness.

pentaxuser

Now you' ve gone and jinxed it. To be fair, even Kodak says using a safelight WILL (not might) affect your results so its no small wonder the myth was born and Endura-ed so long.

 

[Ian Grant]

What's often missed is the amount of stray light there can be in most darkrooms from LED's, illuminated dials on timers and colour heads etc. These are the usual cause of unexplained colour casts or general low level fogging.

Kodak say no safe light, total darkness, however they then go on to say if you must use a safe light you should test it, and keep direct exposures to a minimum with a lamp with a 13 Wratten filter 7.5w bulb at least 4ft away from the paper.

Both Ilford and Kodak warn about keeping safe-light exposure to a minimum with direct exposure, all the colour darkrooms I've seen or heard about (using a safe-light) were using indirect safe-lighting. There are people who've posted here on APUG about using safe-lights for RA4 processing but they know what they are doing. It does need thought and care to ensure there's no chance of fogging.

Initially I put a low energy bulb (equivalent to a 40W tungsten bulb) in my Kodak Beehive lamp with a 10H filter to test it, I could use it direct for B&W work as it's safer than an OC/902.

With a 15w tungsten bulb and 10H filter it's quite dim, initially it's hard to even make out something 4ft directly in front of the lamp and that's Kodak's minimum distance for the less dens 13 filter with a 7.5w bulb. Used indirectly off a ceiling the level would be significantly lower. It's dimmer than the colour safe-light I was using successfully in the past so I will try using it soon when I next do some RA-4 printing, but I'm really only using it to illuminate my timer it will be turned in the opposite direction to the enlarger and Nova slot processor and pointing horizontally at the far wall of the darkroom so not bounced indirectly off the ceiling. In terms of potential fogging the exposure level is negligible compared to brief exposure directly at 4ft.

Mike Wilde talking about a similar colour safe-light filter in (there was a url link here which no longer exists) remarks "After about 20-25 minutes under its illumination my eyes start to perceive the shape of things in the room, and maybe a hint of (false) colour." He's bouncing his indirectly off the ceiling.

Ian

 

[Photo Engineer]

The light from phosphorescent marks on dials, switches and etc. in a darkroom will fog film quite rapidly, but the Wratten #13 will not. I've used both the 10 and the 13, and prefer the 13 for no particular reason other than I have several and that they were on sale at the photo store when I needed them.

They do work with color paper due to the gap in sensitivity between green and red and they do work with Endura as well as earlier versions. The latest Endura has only moved a tiny bit compared to previous versions. There have been 2 changes in sensitivity in my memory, E20 > E30 and E30 > Supra/Endura. The biggest changes were in speed.

PE