proper moisture in a darkroom

[Daniel_OB]

I keep my lenses, photo papers, and enlarger in darkroom, What is the best air mouisture in it to keep all of that stuff uneffected by moisture.
Thanks

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[Robert Hall]

As dry as possible.

 

[DWThomas]

As dry as possible.

Actually, too dry can lead to static and dust clinging problems. I suspect a lower limit of 30% relative humidity is desirable. As a practical matter, in some climates one probably can't get that low, in which case "as dry as possible" fits. I recall that in electronic assembly areas there were guidelines for a range of 40 or so to 60%. Higher than that leads to corrosion and molds, below the low end static discharge can damage parts. I wouldn't want sparks jumping off my fingertips while handling sheet film, for example.

My 2¢

DaveT

 

[Ian Grant]

One thing I'd recommend is store your enlarger lenses outside the darkroom.

One problem particularly in the summer months is moisture getting in-between the elements. This only becomes noticeable when the lens is used and the moisture condenses onto the internal lens surfaces.

Ian

 

[Photo Engineer]

40 - 60% humidity is proper. Dave is correct.

Kodak maintains a solid 50% humidity everywhere in the plant.

PE

 

[Daniel_OB]

Thank to everyone. I just got dehumidifre so will adjust to 40-45%.
Photoengineer, I do not care what kodak do, but rather what you do. Do you keep your lenses in your darkroom permanently (Ian mentioned it is not good).

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[Photo Engineer]

I keep my lenses in my darkroom at 40 - 60% RH. If the humidity goes higher, it does not seem to be a problem. Humidity is very high when I'm coating or when I'm processing color at 100F.

I have stored lenses that way for over 20 years.

PE

 

[dpurdy]

I got concerned with the humidity in my basement dark room when I discovered that all my enlarger lenses were developing haze and fungus. You might do what I did.. go out and get a digital humidity guage.. I think it is called a hygrometer. (They are cheap) I found the humidiy to be generally over 60%. However I took the Hygrometer to different parts of the basement and found that it varies and the driest spot was usually in the 40s%. I now store all my lenses there. I don't think your paper or enlarger is at much risk. At least mine seem unaffected and my enlarger is 40+ years old. I also got a dehumidifier for the basement but it creates so much heat I don't use it when it is hot and humid.

 

[Ian Grant]

Dan, dpurdy is describing exactly what I've found, it has happened in my basement (cellar) darkroom too.

I think its just safer to store the lenses elsewhere.

Ian

 

[Daniel_OB]

My darkroom is also in basement (underground). My dehumidifier has built in RH meter which shows me around 50% RH. But if I do not ventilate it I just feel very high RH, and it is why I got dehumid.
Even PhotoEng. advise it is not a must to remove lenses out of darkroom I think I will remove 'em.
Thanks to all

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[David Brown]

40 - 60% humidity is proper. Dave is correct.

Kodak maintains a solid 50% humidity everywhere in the plant.

PE

I am pleased to read this. I do not have a dehumidifier, but my darkroom does have the luxury of central heat/air. I have a hygrometer, and it almost always reads 50%. In our recent monsoon season, it got up to 60%.

I guess I've just been lucky!

 

[eddym]

I store lenses, cameras, prints, negatives, everything but wine and spirits in a closet in my darkroom. I have a dehumidifier to maintain RH below 50% and an air conditioner to maintain temperature below 80F. But then, I live in a rain forest. We also keep a dehumidifier in our clothes closet.
One exception: when drying FB prints after processing, I turn off the dehumidifier and allow the RH to get up to the 60% range temporarily; otherwise the prints dry too fast and unevenly.