UV Panoramas at the Molas Divide

[OlDoinyo]

US Highway 550 between the towns of Ouray and Durango in Colorado is one of the nation's notable scenic drives, traversing three mountain summits: Red Mountain Pass (3,358m,) Molas Divide (3,330m) and Coal Bank Pass (3,234m.) At the second of these is a scenic overlook with excellent views of the San Juan Range. This past March I passed that way and decided to take advantage of the abundant UV to test out the Horizon S3 with slower film (Kodak Tmax 100 rather than the previous Delta 3200.) Filtration was Tangsinuo ZWB1; development was in Microphen 9 minutes at 20C. I opted for a sepia treatment of the results. (An attempt at full-circle pictures with the Spinner failed when the drive belt stiffened in the cold and prevented proper rotation.)

 

 

 

For these pictures I dared to shoot at wider apertures than f/11 which may have been a mistake as focus shift starts to be evident and the far background is noticeably out of focus. There is some issue with scratches on the film; it is uncertain if the camera is to blame for this, although I have seen it before. The finer-grained film does, however, improve image quality. The expected enhancement of aerial perspective is well-represented here.

 

For visible pictures of the same views see here and here.

[photoni]

3 hours ago, OlDoinyo said:

film Kodak Tmax 100

 

Very interesting and beautiful !

An important note for me: what is the ISO difference between the Velvia 100 and TMAX 100 + ZWB1?

I ask you this because I bought the Rollei Ortho 25 and I don't know how long to extend the time.

Thanks

Antonio

[Doug A]

@OlDoinyothese panoramics are magical. Love the subject and B&W tonalities. How did you decide on the correct exposure? I'd love to try film and UV, but have no idea what exposure to start with. A shame the cold thwarted the Spinner 360° images. 

 

Thanks for sharing,

Doug A

[Andrea B.]

Well done. Such beautiful tones.

 

I gave this topic a Film tag. We don't have too many of those, so this is a good contribution.

[OlDoinyo]

18 hours ago, photoni said:

An important note for me: what is the ISO difference between the Velvia 100 and TMAX 100 + ZWB1?

I ask you this because I bought the Rollei Ortho 25 and I don't know how long to extend the time.

 

The most useful way of approaching this for most (unless your camera allows TTL/TTF metering and responds to the wavelengths being photographed) is working ISO, which I assume you are asking about: first measure the visible daylight falling on a scene, make some assumptions about ratios, and come up with an ISO value that will give you a correct exposure for your invisible-light photograph. I used to shoot quite a bit of Shanghai GP3 100 with both 403 and Baader filters (with the Minolta Autocord TLR) and found a working ISO of 20 for the former and 10 for the latter worked reasonably well. It is worth pointing out that changing to Delta 3200 did not provide 5 extra stops' speed; the reality was more like 2 stops. This is because the difference between faster and slower B&W films is in great measure due to the sensitizers employed in the emulsion, and those are optimized for sensitivity to visible light, not UV; any advantage they provide for UV is not by design and purely incidental. So it is risky to predict the ratio of two films' UV responses based on their visible performance, but one might in general expect them to differ less in visible than in UV. The Tmax 100 with the ZWB1 gave me negatives that were a wee bit thin when exposed at wISO 12; perhaps I should have tried 6 for better results. The Rollei Ortho is an interesting wrinkle because it lacks a red-sensitive emulsion and thus its performance is judged based on a narrower wavelength band. I might try wISO in the range of 3-6 to see where it leads me, but bracketing exposures extensively is de rigueur until you actually nail down the values that work for you. If a film seems excessively slow, push processing is just as possible in UV as it is for visible images.

 

The Velvia was exposed at box speed with no filter.