What do you get when Developing Infrared Unexposed film

Hello all,

I have a question: what do you get if you develop unexposed infrared film? I have read that I can use this developed film as a infrared filter. But when I talked to a guy in one of the online shops, he wasn't 100% sure but said that I will get clear film. He recommended this forum to get definitive answer. I don't normally shoot film, but need IR filter, that will fit into a thin slot at the end of a fisheye lens. Standard poly filters are too thick for this job and I just can't find a foil that could be cut to size and serve as an IR filter.

Thank you very much in advance.

Ren

No, you're somewhat confusing two ideas.

What people do is use unexposed and developed slide film, E6, which as you can imagine would be totally "black". Any film developed as a negative is going to be clear if it's unexposed.

The silver in b&w film would probably impede IR energy too, making for a poor filter; dyes in general (and in E6 particularly) are notably "open ended" in their IR+ transmission, partly to curtail overheating in projection.

Yes, a fully black E6 slide could be used as an infrared filter because infrared goes right through it.

But it would not be good to slide inside a fisheye lens because it would not give you very good image quality.

However you could use a slide over an electronic flash and discreetly shoot at night with it.

Thank you very much to both of you for such a great and fast answers.

Bill Burk said:

Yes, a fully black E6 slide could be used as an infrared filter because infrared goes right through it.

But it would not be good to slide inside a fisheye lens because it would not give you very good image quality.

However you could use a slide over an electronic flash and discreetly shoot at night with it.

Click to expand...

Bill, I have never tried this, but it seems that it could have some interesting possibilities. I enjoyed seeing Weegee's infrared pictures taken with infrared flash, but is there enough infrared emitted by say a compact flash camera, with the flash covered by an non-exposed E6 slide to work in this way?

I think an E6 over an electronic flash would be as effective as a Wratten 87 filter.

I just held a couple slides over the Vivitar 283, in the darkroom and looked at it through the ATN Viper IR monacle.

Get nice bright pops from the flash.

Would anyone here have any unexposed, developed slide film they could mail me? I'll gladly send you a couple stamps, maybe a little Bitcoin, or a PayPal dollar? I'm looking to retire my floppy disks for good.
Thanks very much!!

eatkabab said:

Would anyone here have any unexposed, developed slide film they could mail me? I'll gladly send you a couple stamps, maybe a little Bitcoin, or a PayPal dollar? I'm looking to retire my floppy disks for good.
Thanks very much!!

Click to expand...

How large a piece of film did you need? Actually, I am not sure if I have any at the moment, but if per chance you were wanting to make a Series-VI size filter, I would be happy to send you one of the ones I made:


I can show a comparison between images made with the homemade E6 filter and an "official" IR filter too if anyone is interested.

I didn't use slide film, but I did once make an infrared flash filter by combining cinema gels; looking at the transmission curves suggested that it should have been similar to a Wratten 87. It worked, as far as I could tell, but unfortunately Rollei's IR film is so slow at those wavelengths that it was pretty impractical. If we still had HIE I bet it would have worked a treat.

-NT

Years ago, I got a filter sample pack from Roscolux. The samples are just an inch or so by 3 inches, but that's enough to cut a piece to fit in the back of a fisheye. I originally got the pack to make some orange filters for a microscopy thing at the lab (needed to filter close to a sodium D line to look at the refractive index of glass shards). I don't have the rest of the pack here to see which one I used for the fisheye, but there was one that worked (a dark red). My camera was still able to autofocus and meter through it and I know I have some decent HIE shots using the combo. I don't know if this is quite what you need or not, but it worked for me.