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Astrum IR B+W Negative, or IR-200

I would love to print this image so much in my darkroom:


Unfortunately, I don’t have an enlarger lens that covers 6x7. But at some point I definitely plan to.

It looks absolutely stunning, one of my favorite shots I think I’ve ever taken!
 
Great picture! Love that circular cloud in the corner.
 
Today will be sunny and I've got the bulk rolled 35mm loaded up in the Kiev 4. Should be fun!

 
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Here are my results.

I did HC-110 1+63 for 12 minutes. For most films, that's about a +45% time increase over D-76 stock. The D-76 stock time for Svema Foto 200 and Ilford Delta 100 are both 8.5 minutes, and HC-110 H 1+63 for Delta is 12.

Nevertheless, it's possible it's underdeveloped by a stop or so. But I also think the 720 IR filter doesn't result in a 2 stop reduction to ISO 50. It seems more like 25 at best with it.

I had Acros 100 in the dev tank too. Its normal time is 10 minutes in this developer, resulting in a +20% over-development.

Settings were always for Sunny f/11. So no trickery by a light meter. It was the middle of the day in sunlight in all the shots.

Acros 100:



Svema Foto 200 (no filter):



Svema Foto 200 (Hoya 720 IR):



Still, should be hand-holdable by going down to f/5.6 and developing longer. These will probably scan okay but I don't think you could print them very well. I just got a bulk loader today so that should help from the scratches that came from doing this in a changing bag. This is definitely the thinnest film I've ever used! It's kind of hard to get it on a reel. It wanted to float on top of the bubbles of my Photoflo solution instead of submerging.
 

I need to find my notes for when I developed it in HC-110, but iirc I used HC-110 B for 8 minutes. Not sure how I got that time but it did work well.
 
MCB18 said:
I need to find my notes for when I developed it in HC-110, but iirc I used HC-110 B for 8 minutes. Not sure how I got that time but it did work well.
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Yeah, my bad - my DMax is definitely low on these. I didn't expect the time to be so much higher than the D-76. I will give that a try next time.
 
For anyone interested, I made a document for this film.
 

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  • Astrum IR-200 instructions.pdf
    787.7 KB · Views: 48
Made a decent chunk of this film this weekend, only around 30 rolls till I’m caught up.
 

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  • IMG_5147.jpeg
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lt_col_gordon_tall said:
Those are just Avery labels used to keep the rolls sealed, right? Do they peel away without tearing the backing paper or leaving much residue?
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You just use your fingernail to tear the label where the paper is folded over, and leave it on. I have experimented with several methods of sealing the roll and this is the best way to do it besides masking tape with handwritten label. The big manufacturers like Kodak and Ilford use specially manufactured labels that come off without residue, I suspect they use water activated adhesive and only wet the very ends of the label. I have no way to replicate this.
 
Got my rolls a few days ago. I used a light panel to measure the characteristic curve of a test roll, and for Rodinal 1+50, 10 minutes, rotary dev at 20 C, I get no more than ISO50. I accidentally loaded the roll into my A12 back rather than the A16 back, so I did not get the full curve, but I will post whatever data I do have once the roll has dried.

I am not sure if Rodinal is just not a good developer for this film stock or if the issue is that the light panel does not emit in IR. But I used the same method to characterize Rollei's IR film and got ISO100.

I will shoot a known good film next to verify that my bottle of Rodinal is still fine.
 
To characterize film speed, I assume an ISO, and I use a light panel to shoot frames from 5 stops underexposure to 6 stops overexposure. I define film speed as "4 stops underexposure should give a density of 0.1". I normally do this with an A16 back to cover the whole range, but I accidentally loaded this roll into an A12 back, so there is a big gap in the data and I will redo this test.

"Contact sheet"


Tabulated data


I had assumed that the film speed was ISO100 (=ISO200 - 1 stop for using Rodinal). If the film had indeed been ISO100 then the -4 frame should have given me a density of 0.1, but instead I need an extra 1.5 stops of light to get that density so the film is 1.5 stops slower than metered -> ISO36.

This method of measuring film speed works well with all the usual films, including Rollei Retro 400S (which I am trying to replace with this lot of Astrum). But perhaps the lack of IR in my light panel is messing with the speed characterization of this film stock? I will develop a roll of Rollei 400S next to make sure my developer is fine. If so, I'll redo this curve with the A16 back, perhaps with 1+25 and/or a longer dev time.

I am happy to report that this film dries flat as a board unlike any Rollei stock I have ever used.
 
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