Astrum IR B+W Negative, or IR-200

[MCB18]

Hi all!

I recently bought some “Astrum IR B+W Negative” film (I’m just going to call it IR-200), and was told it was very similar to Foto-200 film, but with a 775nm upper limit into IR as opposed to the typical 750nm. Honestly I thought it wouldn’t make much of a difference, but I bought some just to see. I decided to do an experiment with IR-200 and Foto-200, to see if IR-200 is actually more IR-sensitive like they claim. Right out of the tank, I do think I see a difference. Maybe it’s confirmation bias, idk. Looks like the IR-200 (left) might be like, half a stop faster than regular Foto-200?


These films were shot in 2 different film backs on my RB67 within minutes of each other in the sun with no change in lighting conditions. The film was loaded into the same development tank and developed at 68°F for 8.5 minutes, as suggested by massive dev chart and FPP (who sells the IR film under their own brand). EI from bottom to top of both rolls is 25, 50, 100, 200. (Yes I know, that’s a bit high, I meant to start at EI 12 but accidentally set the wrong shutter speed when I started).

Do you guys have any thoughts on this?

 

[Wolfram Malukker]

Might want to mention, those ISO ratings are when shot through an R72 filter, right?

Do you have some Aviphot that you've shot at 25-40-100-200 through the same filter?

 

[MCB18]

Might want to mention, those ISO ratings are when shot through an R72 filter, right?

Do you have some Aviphot that you've shot at 25-40-100-200 through the same filter?

Yes, this is all through an IR filter.

I might shoot some Foto-100 in the same, which I’m almost certain is Aviphot 200, the same way to see what happens. I suspect it’ll be near identical to Foto-200 based on my past experiences.

 

[MCB18]

Just developed a full roll of this film, and it looks good!

Each of these sets from top to bottom is EI 12, 25, 50:




Control image of visible light at 200 ISO to verify correct development:


And, a quick and dirty invert on my phone:


Honestly, I think EI 12 looks slightly overexposed. EI 25 looks perfect for printing, and EI 50 is maybe a bit underexposed, but for scanning it should be fine.

Pretty cool stuff I think!

 

[koraks]

Yeah, 25 looks good - neat!

 

[MCB18]

I am hoping that I can get them scanned professionally, but my local store is backed up because their lab tech quit… I’ll try to get scans at home.