Konica IR 750 in Pota developer?

[glbeas]

I have a brick of 750 left to shoot and a quick and easy formula for pota. Id like to use the 750 with pota to get the best results, Im thinking it will be similar to using Technidol. Anyone have a developing time starting point with this combo?

 

[Maris]

New Tree, Noosa
Gelatin-silver photograph on Agfa Classic MCC 111 VC FB, image size 21.4cm X 19.4cm, from a Konica IR750 negative
exposed in a Mamiya RB67 rollfilm single lens reflex camera fitted with a 50mm f4.5 lens and #25 red filter.

This one was shot with EI =1 on the light meter. The film went into Xtol-R developer with a mixed batch of other films for
11minutes 15seconds at 20C. Contrast was a pleasant "average" and the negative was easy to print on variable contrast paper
filtered for grade #3. I worry that POTA developers might deliver contrast too low for this film.

 

[BAC1967]

The massive development chart has Technidol.
Massive Dev Chart Konica 750

I've had great results with Ilfosol 3, Rodinal and HC110. The one time I used beerenol (a variation of caffenol with beer) it came out muddy. I think Maris is correct, you want a high contrast developer.

Ilfosol 3
Bishop Hall by Bryan Chernick, on Flickr

Rodinal 1:50
Stone Monoliths by Bryan Chernick, on Flickr

HC110 dilution b
Thunderstorm Over Zuni Mountains by Bryan Chernick, on Flickr

 

[glbeas]

I actually entered the Technidol data in the Massive Dev Chart years ago after noting very similar characteristic between the two films and tried a roll in it. I got a surprising EI of 12 to 24, less grain as well as nice tones. Since Technidol is not easy to find Pota seems the closest thing to it.
This film is naturally contrasty, so a high contrast developer is not desireable especially if you want any detail in the highlights.

 

[Randy Stewart]

I have a brick of 750 left to shoot and a quick and easy formula for pota. Id like to use the 750 with pota to get the best results, Im thinking it will be similar to using Technidol. Anyone have a developing time starting point with this combo?

I would definitely NOT try to develop Konica 750 Infrared film in POTA. POTA was formulated to process extremely high contrast films (like Kodak Technical Pan) into images with relatively long density scales, i.e., process normal film to a extremely flat negative. 750 is a relatively normal contrast film, so its tonal range would be just about destroyed in POTA, just like most other normal B&W films would be. It's been many years since I last processed a roll of 750, but I'd look to a fairly normal developer, such as D-76, maybe Xtol of Ilfosol 3. I seem to recall that Konica printed some developing recommendations on the inside of the film box , ala Kodak, but there must be processing data on line. (And I do not mean from the notoriously unreliable MDC.)

 

[Randy Stewart]

I attach a copy of the Konica data sheet for 750 film, which includes exposure and developing recommendations. POTA would be a very poor choice of developer for 750, because is was formulated to extremely flatten the tonal range. It also reduces the film speed. It was designed to use high contrast copy so shoot bomb blasts to get full tonal images, so it is useless for this film.

 

[glbeas]

Seeing as I got excellent negatives with Technidol I would differ in my opinion here. The problem with this film is the highlights want to block with your average developer. The lower contrast developer helps keep that at bay also helping to bring up the midtones and shadows while keeping the negative printable. I think these effects also have something to do with the higher EI I got using the Technidol as well.