Microwave fogging film or paper?

My darkroom doubles as my kitchen (or should I say that the other way around? ).

Practically, that means I have a seperate cabinet/counter across from the kitchen cabinet counters, which holds my enlarger and has drawers full of film, paper, etc.

One thing I don't have in my kitchen is a microwave oven. I am considering adding one -- but the only spot for it would be on the "darkroom" counter.

Before I put a microwave oven there, is there any risk of the microwave oven fogging my film or paper? The closest film would propably be 1 foot below the oven; paper maybe 2 feet below.

Any suggestions or warnings?

I would think microwaves would be rather long to affect film, but I also don't think I'd want to work next to an appliance that put out enough radiation that could. That said, I have no hard scientific data to back up my position.

Microwave ovens are very well shielded. There is no need for concern. If there are any leaks, it's not your photographic supplies you'll need to worry about. Your EYES have no heat receptors. That means by the time you feel *anything*, your eyes are so damaged you have to give up photography as a hobby.

Personally, I go to great length to NOT mix up photo supplies and food stuff. I'm more afraid of photo stuff getting on to my food stuff, and damaging my photo stuff from water/food spills.

Thanks for the input. Yes, I am fanatical about not cross contaminating. The microwave would be the first/only step across that threshold.

I'd be more careful about any lighted displays on the appliance. These may be dim enough not to cause any noticeable effect on paper, but could cause serious fog to film. Whatever you do, don't turn the appliance on while you have paper or film out. There's a lamp in most that turns on with the device. That, for sure, will fog your film and paper.

You can use it for drying trial prints, though.

Hey everybody.....popcorn in the darkroom!!!

filmamigo said:

Thanks for the input. Yes, I am fanatical about not cross contaminating. The microwave would be the first/only step across that threshold.

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Its a slippery slope.

microwave is not an x-ray machine, your film is safe.

Microwaves are in between long infrared and short radio waves - kitchen microwave ovens have ~millimeter wavelengths (hence the coarse metal screen in the microwave oven window, which is effectively opaque to microwave radiation).

The photon energy is very low compared to visible light; the reason they cook food is that various molecules in food oscillate and heat up under microwave radiation (according to my physics professor in college). I too would be more worried about the control panel lighting.

Actually... most microwave ovens use around 2 to 3 GHz. Wave length at these frequencies are around 10cm or a tad longer. Either way, photographic films and papers aren't sensitive to these frequency.

tkamiya said:

Actually... most microwave ovens use around 2 to 3 GHz. Wave length at these frequencies are around 10cm or a tad longer. Either way, photographic films and papers aren't sensitive to these frequency.

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That's what the tilda in front of "millimeter" was all about.

After having our fairly new microwave oven in our home tested, we unplugged it for good.
We had no idea how far the emissions reached.

marcus schluschen said:

After having our fairly new microwave oven in our home tested, we unplugged it for good.
We had no idea how far the emissions reached.

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Yet you sit in front of a computer and probably use a cell phone...

yum

fschifano said:

Yet you sit in front of a computer and probably use a cell phone...

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don't forget all the growth hormones in beef

Our non wireless computer was tested up close and the reading was very low.
The reading for the microwave oven on the other hand, was taken not in front of the appliance, but on the opposite side of the house, far away from the kitchen. We could not believe it! Apparently this is not out of the norm.
We do not own or use cell phones and the phones that we do use, are plugged into the wall.
Growth hormones in beef? Sorry, not allowed in our country.
Getting back to the original posting of Filmamigo, I would be very cautious after our experience.

Marcus,

Because you said you had your microwave tested and doubted in its effects to printing papers, I just did a little experiment.

In my darkroom, I placed a small clip of Ilford Multi-grade printing paper into a black light proof bag and sealed it shut with a tape. Then, took this bag of paper and placed it in my 800 watts microwave. Please note, I placed this bag IN the microwave itself. I also placed a cup of water as a load. (never run microwave ovens empty!). Then, I turned it on for 15 seconds at full power.

I chose 15 seconds as if there are small amount of moisture in the paper, it will generate heat and heat, not microwave energy can fog the paper - skewing the result. I decided to use relatively short burst for this reason. The black bag I used is just plastic, not metallic.

Please note, we are now talking about full 800 watts of 2.something GHz of microwave power, less what was absorbed by a cup of water. I am not talking about leakage out of the microwave. If microwave chambers are shielded at 60dB attenuation (which is typical), what leaks out is 0.8 milli-watts. It takes quite a while to accumulate the same amount of energy as my test.

Then, in my darkroom, I developed in Dektol, put it in stop bath and viewed the result.

The paper is white with no signs of exposure.

Based on this test, I have absolutely no doubt there will be no effects from leaking RF energy on photographic papers. I have not tested film but I am reasonably certain, there will be no effects. I can test it at later date with film if you wish.

I don't know how you had your microwave tested, but please be very aware, an only accurate way to test leakage is by spectrum analyzers or similar very expensive lab equipments. Inexpensive field strength meter does not discriminate between magnetic fields from transformers (60Hz) to microwave energy leakage. I am *guessing* there will be some flux leakage from transformers - which are harmless. If this was the case, it makes sense it was stronger in the back than the front.

Anyway, it seems very safe for photographic papers.