Rosco Gel equivalent of OC safelight filter

pdccamerqs

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Sorry if this has been covered previously, but I did not find a definitive answer in previous posts. I am in the process of setting up my 10'x16' (3m x 5m) darkroom and I have a number (5) of beehive style 5.5" round Kodak safelights with OC amber filters. I have not done the Kodak K4 safelight test yet as my enlargers aren't set up yet, but based on the age of my filters, I am assuming I may need new ones. My lights are pointed down at the sink from ceiling height, about 53"(1.4m) above the paper trays. They are equipped with 15watt frosted bulbs. I predominantly will work with Ilford MG paper, and possibly do some ortho/litho work as well.

My questions:

1) Is there a Rosco gel equivalent for the Kodak OC amber filter I can use in the Kodak safelight? If so, what is the Rosco #.
2) Is the Rosco #27 red filter in a Kodak safelight OK for ortho/litho work?
3) Has anyone tried one of these Arista orange safelights with Ilford MG paper?



Thanks for your help with these questions.

Best,

Paul
 

Pieter12

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If the safelights have not been used much and not stored in bright lighting conditions, I am not sure they may have faded as you assume. Do a test before getting too deep into replacing the filters or the safelights themselves.
 

Loose Gravel

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Orange doesn't fade quickly, but absolutely do the test. And pre-expose your test first. Get up to the threshold value of exposure for your paper so the test is representative of a print.

If you're not sold on orange/amber, use a red LED bulb and forget the filter. Better for ortho, too.

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Nicholas Lindan

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I have never been able to find the spectral curves for any of the Kodak safelight filters. I was also trying to find a Rosco gel to use in a safelight - but no luck. I gave up and bought a filter on ebay.

It shouldn't be too hard to try the orange or red filters in a Roscolux sample book - place a small bit of paper under the filter gel and expose it to a white light, develop and see what results.

My guess is a Rosco #27 would make a good safelight filter.

A better choice might be Rubylith https://shop.archsupplies.com/products/rublylith-masking-film-20x24 Amberlith was discontinued some time back, but NOS might occasionally pop up.
 
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reddesert

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Nicholas Lindan said:
I have never been able to find the spectral curves for any of the Kodak safelight filters. I was also trying to find a Rosco gel to use in a safelight - but no luck. I gave up and bought a filter on ebay.
Click to expand...

Really? The safelight curves are here: https://www.kodak.com/en/motion/page/safelight-filters/
I found them a week or so ago when I was admonishing people not to try using a safelight filter as an eclipse solar filter. For ex the Kodak OC light amber filter curve pdf is attached. It has a transmission peak around 580 nm (transmission increases downward on these plots), perhaps tuned to the emission of a sodium lamp. I don't know if there is a similar Rosco.

(Most of the safelight filters have between 10-80% transmittance in the near-IR longward of 900 nm or so, which is ok for most non-IR sensitive photographic materials, but terrible as a solar filter.)
 

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pdccamerqs

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Thanks all - I will be testing my existing setup prior to making any changes (thanks Pieter12!). Also great resource, redessert, I compared the Kodak OC transmission curve to a typical Roscolux (you can get all the Rosco transmission curves here: https://us.rosco.com/en/products/catalog/roscolux

Here's the Kodak OC transmission curve, which is below 1% transmission between approx. 650 and 825 nm.



Compare that to the curve for a Roscolux Roscosun 85 + .6ND




The transmission ranges from 24% to 59% over roughly the same range. Perhaps doubling up the Roscolux filters or adding more ND could get closer to the OC, or possibly sandwiching in a different color Roscolux which has a lower transmission between 680 and 800 nm?

Best,

Paul
 

Nicholas Lindan

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eli griggs

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I suggest you look up the Rosco 'gel' filters recommended for the 30W Thomas Sodium Safe Light.

I put new ones in a few years back and have had no issues.

Bought at my local Barbizon Theater supply for the about $8 each, they are very large and scissor work or hobby knife is the order of the day.
 

Mr Bill

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Nicholas Lindan said:
I have never been able to find the spectral curves for any of the Kodak safelight filters.
Click to expand...

Hi, for possible future use the "Kodak Photographic Filter Handbook" (pub B-3) also shows spectral curves for a variety of safelight filters. My 1997 copy covers 14 filters (page 72-79).

Also, as I recall (fuzzy memory), the CRC Handbook of Chemistry and Physics also has tabulated data for a number of Wratten filters. (I don't recall if any safelights are included; if anyone is seriously interested I'll take a look.)
 

Doremus Scudder

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Safelight filters to fit the old Kodak beehive safelights as well as 10x12" filters for the D and C models come up regularly on eBay and other photo auction sites. If you really need to replace them (and I think likely not if you have OEM Kodak glass filters to begin with and they haven't been in a commercial darkroom for 20 years), then look for some genuine replacements.

I use Kodak beehives, a Model D bounced off the ceiling and a string of red LEDs behind a strip of rubylith tape. I use OC and 1A (light red) filters for the most part. All of the above pass the Kodak safelight test with room to spare. I imagine yours will too as long as you keep the wattage in the beehive safelights to 15W or even 7.5W.

Best,

Doremus
 

btaylor

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Neal said:
I use Roscolux #19 fire.
Click to expand...

Yes, that’s one of the filters I got to re-filter my Thomas safelight.
OP, you might look up the “Naked Photographer” on YouTube, he goes into specific detail on the Rosco gels. I would imagine they would work well with the beehive too.
 

Pieter12

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Isn't the Thomas a sodium light? Wouldn't that mean a different filter would be needed for the beehive with a tungsten bulb?
 
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pdccamerqs

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will do! Thanks for the tip.
 

nhenning

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Hi there,

I'm just wondering if you ever found the answer to your question of whether there is a Rosco gel equivalent to replace OC amber filters?

I work for a university and need to replace some that are mounted in the ceiling because they have cracked and really don't do much to filter out the light anymore.

Thank you for your time,
Nick
 

RalphLambrecht

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Pieter12 said:
If the safelights have not been used much and not stored in bright lighting conditions, I am not sure they may have faded as you assume. Do a test before getting too deep into replacing the filters or the safelights themselves.
Click to expand...

I'm very picky with safelights in the darkroom because getting brilliant whites without good safelights is nearly impossible. After numerous tests, I went with light red safelight filters and 15W bulbs. The red safelights needed getting used to but they provide safe lighting for MG papers now.
 

ags2mikon

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eli griggs

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Barbazon, gels should be able to tell you.

Remember, it'll take two different hours but will not be expensive.

I'd look it up but am away from home for a few days.

Cheers.
 

eli griggs

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I've used amberlith to good effect but it's been years since I last did, though I do have a mini maglight with a couple layers of filtration.
 
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