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

[axs810]

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.

Alright I'll get on a test right now and report back in awhile.

[Ken Lee]

Excellent.

It's important to not deal with film that you've loaded into holders, exposed, and removed from holders.

If we want to determine if the IR device is fogging, we need to remove all the other variables.

[axs810]

Alright so I have some good news! I was wrong the ATN Viper Night Vision goggles don't fog film!

For this test I didn't go out and buy brand new film because of personal limitations but it didn't matter.

Here is what I did:
- Sealed off darkroom using Delta 1 Black out plastic + unscrewed lightbulbs in bathroom
- Sat in darkroom for 5 min and couldn't see any light coming in so I put on the IR goggles and looked around..nothing I could see so I started
- pulled out one new negative from the box (hasn't been exposed to light, loaded in a film holder, etc just pulled out and thrown in developer)
- I let 5 min go by then put it in the stop and fix - resulting negative is clear
- Next I take a new negative out from the box (hasn't been exposed to light, loaded in a film holder, etc julled pulled out and thrown in the developer)
- 5 min go by as I stare at the negative with the IR Goggles then put it in the stop and fix - resulting negative is clear or the same

BUT as I'm fixing the last negative I turn around and notice the Delta 1 black out plastic isn't fully blocking the out light anymore...so I asked someone to check the outside and see if it was still sealed. It was sealed perfectly but there was just barely a little light coming through the plastic and now I think I know how my film got fogged before. My bathroom doors have a big enough gap around the edges so it allows light to creep through the cracks of the frame. When I develop my film I sometimes do 3-4 batches of 5 in a row. So maybe I was in there for too long and that very small amount of light coming in through the plastic slowly fogged my film. My bathroom doesn't have any windows so the door is the only factor I can think of...



This is the Black Out Plastic I use.... *thumbs down*

http://www.freestylephoto.biz/423416...-x-16-ft.-roll

[Ken Lee]

That's good news !

[Tin Can]

Alright so I have some good news! I was wrong the ATN Viper Night Vision goggles don't fog film!

For this test I didn't go out and buy brand new film because of personal limitations but it didn't matter.

Here is what I did:
- Sealed off darkroom using Delta 1 Black out plastic + unscrewed lightbulbs in bathroom
- Sat in darkroom for 5 min and couldn't see any light coming in so I put on the IR goggles and looked around..nothing I could see so I started
- pulled out one new negative from the box (hasn't been exposed to light, loaded in a film holder, etc just pulled out and thrown in developer)
- I let 5 min go by then put it in the stop and fix - resulting negative is clear
- Next I take a new negative out from the box (hasn't been exposed to light, loaded in a film holder, etc julled pulled out and thrown in the developer)
- 5 min go by as I stare at the negative with the IR Goggles then put it in the stop and fix - resulting negative is clear or the same

BUT as I'm fixing the last negative I turn around and notice the Delta 1 black out plastic isn't fully blocking the out light anymore...so I asked someone to check the outside and see if it was still sealed. It was sealed perfectly but there was just barely a little light coming through the plastic and now I think I know how my film got fogged before. My bathroom doors have a big enough gap around the edges so it allows light to creep through the cracks of the frame. When I develop my film I sometimes do 3-4 batches of 5 in a row. So maybe I was in there for too long and that very small amount of light coming in through the plastic slowly fogged my film. My bathroom doesn't have any windows so the door is the only factor I can think of...



This is the Black Out Plastic I use.... *thumbs down*

http://www.freestylephoto.biz/423416...-x-16-ft.-roll

I used the same Delta Black out Plastic, but I did it differently.

I had 80 sq ft of direct southern exposure with clear glass brick. My first layer was a combination of silver reflective insulation over foam core, not fully light tight. Inside the window space I left Chicago made objects for street side viewing including a complete Schwinn bike, like time capsule.

Then 1/4" plywood on studs 12" from glass block. I carefully covered that with the Delta product, taping all seams and corners. Finally I covered the Delta with 5x16" pine tongue and groove, some gaps.

I test by sitting for 20 minutes and see no light or glow at all even with direct sun.

If it ever leaks. I will apply another layer of Delta and paneling.

I gained a full black out darkroom, soundproofing and insulation.

Since I sleep in the far corner with every light source off, I wake to full cave and it takes a while for my eyes to adjust.

The weird thing is the stuff I see just after awakening with eyes wide open. It's like a dream but I 'see' photographic type images that are constantly different. I am not seeing the room contents, but people, as if in posed portraits. I don't know them either.

Then I bring on the day with a slow rising dim light, manual control. No alarm clock ever used unless absolutely necessary. Like today for Dr appointment.

I used to use an Astronomic timer, but I dislike not being able to sleep in. However I still use it for my HEPA filter as the noise is best tolerated during REM. I may be setting a natural Astronomic rhythm from noise not light.

Any light while sleeping now bothers me...

I like the dark.

[axs810]

I wish I could set up something more permanent like that but unfortunately my set up has to be able to put up and take down quickly. If I did have to battle any windows though I do like your idea of the silver reflective insulation over foam core along with the blackout plastic.

[Bill Burk]

axs810,

Glad you found your light leak. I did a test with a step wedge and a long exposure to close proximity to the full-intensity IR light (TMY-2).

Based on those results...

I chose to "attenuate" the IR light with a piece of silver film with density 0.60 (note E-6 slides are completely transparent to IR so it must be silver film or some other light blocking material that really blocks IR). I found an old negative from a rodeo that I could spare where the arena dirt was 0.60. So I cut the negative in a circle and glued it to the light with contact cement. Occasionally it falls off and needs re-gluing but that's all the maintenance it needs.

http://www.largeformatphotography.in...Darkroom/page7

[axs810]

Thanks for sharing that thread! I'll read the whole thing later but it was interesting to see your results with the step wedge. I applaud your patience lol...


I guess just in case I'll play it cautious too and put a piece of silver film with a density of .6 in front of my IR too. Thanks for the tip!

[Ken Lee]

I have changed the title of this thread so that people won't get the wrong idea and jump in with advice without having reading any of the actual discussion.

[axs810]

^__^