Questions Re ATN Viper in Darkroom

[George W.]

How about using a filter in front of your IR illuminator,
that just lets pass IR, and cutting all visible light?

Couldn't you use the same filter being used in IR photography
for cutting off all visible light?

The only difficulty would be how to attach this filter to the rest(?)

[Michael Kadillak]

How about using a filter in front of your IR illuminator,
that just lets pass IR, and cutting all visible light?

Couldn't you use the same filter being used in IR photography
for cutting off all visible light?

The only difficulty would be how to attach this filter to the rest(?)

Surely that would work. Rather than fuss around with trying to find some filter material assuming that it is up to the task and find a way to affix it to the monocle I took the easy route.

IR LED light banks are cheap and turning them away from your work area so that only IR light is reflected back to where you need it is quick and easy. It is not as luminous as having the IR light blazing directly in front of you but it comes without the added baggage.

A while back there was a guy at another forum came up with the idea to use glass trays to develop one sheet of film at a time about foot above a large scale series of LED IR light banks that claimed to have zero increase in fog levels with his set up. I told him to put water in his tray and leave an unexposed sheet in there above the IR light source and in total darkness develop it with a second sheet straight from his film box and put them side by side on a light box and I never hear another word.

[jeroldharter]

I don't use mine to develop film, just to load film holders, reels, and drums. Nevertheless, I would like to avoid any fogging.

Michael, do you have a source for the IR LED lights that you use? Thanks.

[Michael Kadillak]

I don't use mine to develop film, just to load film holders, reels, and drums. Nevertheless, I would like to avoid any fogging.

Michael, do you have a source for the IR LED lights that you use? Thanks.

It has been several years since I acquired my LED IR light bank and I am not sure where I got it But I would be happy to see if a comparable product can be located.

Since there are a wide range of variables in this unique application of IR in photography, I would strongly encourage anyone that is using this system to expend a sheet of 4x5 film and a small allocation of your time as Ken is doing perform a quick test and see for yourself what your specific situation involves.

I purposefully tested my worse case scenario in using the highest ASA film with my monocle. But other devices and other choices of sheet film will likely arrive at different results. I am simply advocating that we see the net effect one way or another and make the best decision for each of us.

[Keith Pitman]

I don't use mine to develop film, just to load film holders, reels, and drums. Nevertheless, I would like to avoid any fogging.

Michael, do you have a source for the IR LED lights that you use? Thanks.

Jerold,

You can find IR illuminators inexpensively on Ebay.

Just to add to Michael's testing results, I've also found that both the light from the Viper and the separate illuminator can fog film. I got fog from the illuminator positioned about eight feet away and aimed away from the film (ISO400). I need to work with this some more to find a way to aim the illuminator that will eliminate the fog risk.

Good tool, but it needs to be used carefully.

[Michael Kadillak]

Jerold,

You can find IR illuminators inexpensively on Ebay.

Just to add to Michael's testing results, I've also found that both the light from the Viper and the separate illuminator can fog film. I got fog from the illuminator positioned about eight feet away and aimed away from the film (ISO400). I need to work with this some more to find a way to aim the illuminator that will eliminate the fog risk.

Good tool, but it needs to be used carefully.

Thanks for sharing your experiences Keith. Every time I hear people say on this forum and other places casually state that "no increase in film density has been experienced" with the use of the IR monocle absent supporting comments for these statements I cringe. I guess getting tattooed in corporate management presentation meetings early in my engineering career for lacking technical support or making bold assumptions has stuck with me over these years.

I turn my LED light bank directly into an adjacent wall in my darkroom and bounce IR into the room and tests have shown negligible added FB+F. But maybe I should do another test just to make sure.

[Michael Kadillak]

Ebay item #120562530863 appears to be an LED IR supply light bank similar to what I previously acquired. There are many like this offered from Hong Kong or China that do not have a power supply cord.

I would want to make sure that the domestic seller includes a power supply cord included in the sale.

[IanMazursky]

Ian, have you tried wearing your Yankees cap, turned backwards like a catcher, and putting the Viper headgear on over the cap?

BTW, Michael Kadillak has tested the IR light on the Viper and has found it does cause fogging--check out this post for a solution (scan down to post #20):
http://www.largeformatphotography.in...t=13322&page=2

Michael, Thanks for the suggestion! I will have to give that a try. A cap might just eat up enough slack to make the headgear fit.

I think the little IR emitter on the ATN could fog film if its left exposed. You can see a little red dot when its turned on.
Thats why i wrap one of those white rags in a box (folded over a few times) over the emitter.
You cant see the red light anymore but it does seem to pass a small amount of IR through and light up the room just enough.
So far its been fine for B&W and color film. No fogging that i can see on any LF or Aerial film.
But i haven’t done exhaustive testing, as they say YMMV.

[George W.]

see following tutotial on IR diodes
http://www.gizmology.net/LEDs.htm

it clearly states:

""HOWEVER - keep in mind that LEDs are not perfectly monochromatic. If
their peak output is close to the visible spectrum, then their bandwidth may overlap
the visible spectrum enough to be visible as a dim cherry-red light. Furthermore, some
people can see further into the red region than can others, seeing as deep-red colors
that to others are invisible infrared. While it would be possible to give such an LED a
rating in millicandella, it would be misleading. ""

this should be warning enough to *not* use near-IR diodes with unknown spectrum distribution

I guess that far-IR diodes might be less exposed to this phenomena, but I have no
idea up to what wavelength in the far-IR the detectors in the Viper work

[Michael Kadillak]

see following tutotial on IR diodes
http://www.gizmology.net/LEDs.htm

it clearly states:


this should be warning enough to *not* use near-IR diodes with unknown spectrum distribution

I guess that far-IR diodes might be less exposed to this phenomena, but I have no
idea up to what wavelength in the far-IR the detectors in the Viper work

Excellent reference material George. I agree that knowing the spectrum distribution is an excellent first step. Even with this information testing is the only way to adequately put this tool to proper use.