Developing ultra low ISO films for direct duplicating

[koraks]

Well, you got an image (and perhaps a little mishap with the bulk loader; I tink I recognize the problem...) I find it hard/impossible to tell what the spectral sensitivity is. Let's wait and see what an actual prism gives.

 

[Wolfram Malukker]

That film appears to be ortho sensitized. It does catch a little of the red/orange spectrum. Certainly not the the level of the indigo, blue region, or even the green/yellow region, but it isn't completely blind to orange/red at 0.3 ISO. Comparing the 1.5ISO image, you can still see a faint line where the red wavelengths are landing on the background canvas.

Koraks, the glass crystal is acting as an actual prism, a "real" triangular prism will give a very similar/identical result.

 

[koraks]

Koraks, the glass crystal is acting as an actual prism, a "real" triangular prism will give a very similar/identical result.

I understand what we're looking at. Again, try again with a proper prism. Given the discontinuity of the spectrum (more patches, actually) this crystal projects, it's hard to say anything conclusive.

 

[Yezishu]

Another roll of Kodak 2468 development results, and thanks to @koraks.
Shot at 0.3~0.6 ISO. Developed in PC-TEA (Phenidone and Ascorbic Acid, 1:25), agitated for the first 5 minutes, then left to stand for 20 minutes at 20°C.

As slides, the development failed, and the image was very pale (the unexposed part should be completely black, but it was only light gray). I didn't expect that the purchased PCTEA (Phenidone, works well in fomapan 100) and the previous homemade PCTEA-variant (Dimezone S) would be so different. This result is similar to “https://www.aperturepreview.com/an-unknown-positive-microfilm.”

Combining our results, I believe D76, HC110 and standard PCTEA are not very effective here, while PCTEA (Dimezone S) and D8 have good results.

 

[Yezishu]

One more roll of Kodak 2468 developed in PCTEA-variant (Dimezone S), with half frame camera(OLYMPUS Pen D2), 0.8~1.0 EI, result in high-contrast imges.

 

[corydon]

Hi,

I just got some Kodak 2468 35mm rolls for practice. I was told the ISO is 0.8, The lowest ISO of my Canon EOS630 is 6, and it has up to +/-5 EVs compensation range with 1/2EV step. My understanding ISO 6 ; 3; 1.5; 0,75 need 2x exposure time in between (1EV span). To get correct exposure combination, is the ISO6 + 3EVs compensation would work? Someone told me have to be +5 EVs . I am confused Thanks!

 

[Yezishu]

Hi,

I just got some Kodak 2468 35mm rolls for practice. I was told the ISO is 0.8, The lowest ISO of my Canon EOS630 is 6, and it has up to +/-5 EVs compensation range with 1/2EV step. My understanding ISO 6 ; 3; 1.5; 0,75 need 2x exposure time in between (1EV span). To get correct exposure combination, is the ISO6 + 3EVs compensation would work? Someone told me have to be +5 EVs . I am confused Thanks!

You're correct, using ISO 6/+3EV result in an ISO of 0.75. I also recommend a +5 EV adjustment, which is about 0.2 ISO, if possible. Giving the film more light will reduce contrast and improve the grayscale transitions.