Safelight question

[gphoto120]

Does anyone know if a Kodak #13 amber safelight filter is safe w/ Ilford MG /Kentmere MG papers? Ilford's website says any safelight compatible w/ B&W papers can be used ...then later states a Kodak OC filter (light amber).
My reason for asking is I can buy an 8X10 #13 amber filter for 10.00 but the OC light amber filter is 63.00.

 

[Ian Grant]

It should be safer than a Light Amber

There are problems with some Red safelights and Multigrade papers.

Ian

 

[RalphLambrecht]

There are problems with some Red safelights and Multigrade papers.

Ian

Ian

Why do you say that?

The darker the safelight is and the more towards red it is, the safer. Amber safelights are about the minimum for MG-IV. Dark or light red are 'safer' but harder for the human eye to see in. Consulting the wavelenght vs sensitivity specifications for paper and filter should provide the answer for any specific combination.

 

[Photo Engineer]

It should be safer than a Light Amber

There are problems with some Red safelights and Multigrade papers.

Ian

Multigrade papers are blue and green sensitive, therefore dark yellow, amber and red will be safe with these papers.

I have posted the wedge spectrogram of Ilford MGIV here elsewhere.

PE

 

[dancqu]

Safelight color is one of at least three variables.
Intensity and duration of exposure are another two.

Paper handled in a manor which allows for little
exposure to the safelight can bring higher over-all
darkroom lighting levels. The light's pattern of
distribution is important. Dan

 

[gphoto120]

Thanks for the quick responses!

 

[Photo Engineer]

Safelight color is one of at least three variables.
Intensity and duration of exposure are another two.

Paper handled in a manor which allows for little
exposure to the safelight can bring higher over-all
darkroom lighting levels. The light's pattern of
distribution is important. Dan

Dan;

It has to be a mighty flimsy safelight for what you state above to take place.

If a photographic material has no sensitivity to a particular region of light such as red, then if the red filter on the safelight has been properly designed to eliminate all other types but 'red', there is little or no problem with duration or intensity.

Use of inexpensive, poorly designed, or damaged filters can do what you say, but good ones will not. I have fogged blue sensitive emulsions with red safelights that were transparent to some blue light due to their design. A safelight filter, properly designed, is a true cutoff filter which allows no incorrect illumination to pass through.

It would be like putting a heavy opaque filter intended for IR photography over your camera lens and expect to be able to take IR pictures with a normal film. Neither intensity nor duration will allow this to take place, as the film is not sensitive in that region of the spectrum. And, it would require a very very long exposure under brilliant light to penetrate one of these "black" filters as they are true cutoff filters which eliminate the entire visible part of the spectrum.

PE