ATN Viper Night Vision Goggles - I thought I might be getting fogging

[axs810]

I bought these wanting to try it out but once I used them I noticed I kept getting a slight fogging on my film when wearing this unit. I cannot figure out why I am getting a very light fog but it keeps happening very slightly and with what seems to be a more pronounced grain structure. (I develop 320txp for 4:30-6min in HC110B)


Things I have tried-
- Keeping the cap on while using night vision (the one that is like a pinhole cover)
- Taking the cap off and covering the IR light with a napkin
- Keeping the night vision unit close to my face to prevent light from bouncing off my face and onto the film


I wear the unit and watch the film develop the whole time could that be my problem? Also, I manually focus the lens and look at my trays does everyone else do that? Just curious because I know everyone else has good luck with these so I know it's probably something I'm doing wrong but can't seem to figure it out. Help me?

[Drew Bedo]

I don't know anyting about these goggles specifically, but . . .any "night vision" technology must use some light energy to produce a visable image. the light amplification or "starlight" technology uses feint ambient light in the visable range . . .moonlight or starlight . . .but there must already be some amount of visable light to be amplified.

The IR technologies use infra-red energy in wavelengths too long to be visable to the human eye, and converts that into wavelengths in the visable spectrum . . .usually green. Your goggles may have an infra-red illuminator shining onto the film.

Perhaps your film has an IR sensitivity. Another guess is that the fog is caused by the green light coming rom the eyepiece end of the equipment.

[Bob Mann]

I have been using Vipers for a few years and have a few thoughts:

I wear the unit and watch the film develop the whole time could that be my problem?

Are you tray processing? Or using dip tanks? I use vipers with dip tanks and have never had an issue with fog. I have also done tray processing without problems.

Taking the cap off and covering the IR light with a napkin

Not sure how much a napkin would cut IR output from the LED, the lens cap should have no affect - I leave my lens cap on most of the time because of the greater depth of field.

Have you looked around your "darkroom" with the Vipers on for other light leaks?

seems to be a more pronounced grain structure

Wouldn't grain be the result of chemistry, not IR exposure? Are you using a different developer?

[jasonphoto01]

Are you using night vision or infrared? What model goggles are they?

[sun of sand]

Before I tried night vision I used to use the green illumination from a watch dial in short bursts throughout development to watch it progress

I never noticed any fogging.

I'd think that fog much quicker than the goggles so I'd look elsewhere first

[Ken Lee]

You might find it helpful to do a rigorous test to find out if the film is fogged already, if the IR device is responsible, both or neither.

First, get 2 sheets of film which have never been subjected to illumination from this device. The best choice would be a brand new box of film, unopened and therefore not previously fogged. This presumes that your darkroom is light tight.

Cover 50% of the first sheet with someone completely opaque like a book. Subject the first sheet to illumination from the device, at the distance you typically work. Do this for 10 minutes.

The second sheet should come right out of the box, never exposed to anything at all.

Next, in total darkness, process both sheets in the usual manner.

Next, compare the 2 sheets. If no fogging is present, they should look the same. If there is fogging from the IR device, you will know how much. If the film is already fogged for some other reason, you will know that too.

Without a rigorous test, your efforts may be just... speculative.

[Harold_4074]

A slightly more rigorous test would involve deliberately fogging a sheet of film to barely detectable density, then performing the half-and-half exposure test as described by Ken Lee.

In a real camera, there is always some scattered light, which is usually lost down in the base-plus-fog region of the characteristic curve (deep in the "toe" region). Adding a very small amount of additional light may being the exposure up onto the curve far enough to be objectionable, even though that exposure by itself on otherwise pristine film would not be noticeable. (This is the rationale behind the Kodak safelight testing procedure, discussed at great length elsewhere.)

[axs810]

Bob Mann: I have been using Vipers for a few years and have a few thoughts:


Are you tray processing? Or using dip tanks? I use vipers with dip tanks and have never had an issue with fog. I have also done tray processing without problems.

I am tray processing.


Not sure how much a napkin would cut IR output from the LED, the lens cap should have no affect - I leave my lens cap on most of the time because of the greater depth of field.

Have you looked around your "darkroom" with the Vipers on for other light leaks?

I clog the napkin over the LED until I can't visibly see it with my naked eye. The napkin kind of acts as a diffuser in case it was fogging I would be able to see a difference but that idea didn't really help too much. When you mention leaving your lens cap on to get a greater depth of field what do you mean really? When I look through the lens cap its like trying to look through a hole the size of a toothpick but when I take it off I can adjust focus and get a 5x7 tray size view of what I am doing (in focus vs with the cap fuzzy focus toothpick hole)

I have looked around my darkroom with the night vision on and found no light leaks.


Wouldn't grain be the result of chemistry, not IR exposure? Are you using a different developer?

My bad I just remembered that once I found out I was getting some fogging I bought a box of hp5 so I wouldn't waste my precious 320txp. So I was thinking about the wrong film but did still have a very weird look to it. The negative looked like it had some sort of base exposure over the camera exposure which resulted in looking like the negative had more pronounced grain everywhere but might not have.

[axs810]

Are you using night vision or infrared? What model goggles are they?

ATN Viper Night Vision Goggles with IR Illuminator. I got the same one that's on Ken Lee's tech website.

[axs810]

Before I tried night vision I used to use the green illumination from a watch dial in short bursts throughout development to watch it progress

I never noticed any fogging.

I'd think that fog much quicker than the goggles so I'd look elsewhere first

I have looked elsewhere and still couldn't find an answer so I came here. I usually spend 20 min making sure my bathroom is light tight then when I am certain I have someone close me in by taping black out plastic clothe over the outside of the door while I do the same to the inside.