Much appreciated xkaesOriginally Posted by xkaes
T
Much appreciated xkaes
T
Just one thing, with very old film, ISO / ASA speed changed in 1960. A pre 1960 ASA 100 it is the same than ASA 200 post 1960, see here ASA section: https://en.wikipedia.org/wiki/Film_speed.
Still the actual speed may have changed a lot with aging, so a test should be done.
The ASA that I listed, from Kodak's F-5 publication, lists SUPER-XX at ASA 200, and Tri-X at ASA 400, so I assume that Kodak rated both AFTER the change. In any case, it's best to run some sort of test, even without the added problems of age and storage conditions.
It should be this, I've just found that Super-XX was ASA 100 before 1960 and ASA 200 after 1960:
"Speed: Daylight ASA 100, later 200, when safety factor was reduced" https://en.wikipedia.org/wiki/List_o...Kodak_Super-XX
It also says that it was made until 1992 in sheets, but roll formats were discontinued as early as 1960, 32 years earlier !!
I guess that Karsh success with Super-XX could be a contributing factor for the extended product life in the sheet formats...
It was the main colour separation film for dye transfer from transparencies etc & that's why it lasted till 1992 in sheets, but no longer. It had specific qualities that matched dye transfer well in terms of colour sensitivity etc. The BW fine art market was small potatoes in comparison & quantity of film used. Main markets were not Adams/ Weston/ Karsh wannabes, but rather people making dye transfers for publication, advertising etc involving compositing , retouching, colour replacement/ alteration etc that Photoshop rapidly displaced it from.
I was not aware of that...
Anyway it was an important emulsion, I knew about Super-XX when reading about Citizen Kane cinematography, Toland made a nice job with it...
Super-XX was Kodak's 'fast' film from the 1940s. Speed and grain-wise it was surpassed by Tri-X Pan, which was introduced around 1954. So the smaller formats disappeared quickly. A look at the curves show that the color sensitivity curves lay right on top of one another- vital when shooting separations. And it had a straight line forever- useful for alt-process photographers. Michael A. Smith and Paula Chamlee are the Super-XX die-hards- they bought a large amount of the last batches in 1992 and are still using it, printing through the inevitable fog.
Nice to know that Smith/Chamlee are Super-XX lovers. I had been reading some proficient photographers stating they strongly preferred Super-XX vs Tri... of even saying that it simply was much better for their work.
It would be interesting to know why they love it. By now I simply know that I'm not able to emulate (or copy) the Karsh footprint (not extrange...) , but I'd like to know what was in Super-XX that made him love it.
What's about grain/sharpness, IMHO Super-XX was not a good color separation film, in special if enlargements had to be made. Color separation film is usually low speed, sharp and fine grain.
Anyway IMHO it has some good "filmic" features for that: long straight line, so it still could be a choice for those works not requiring fine grain/sharpness, if price was good.
About spectral sensitivity, for color separations requisite is that spectral sensitivity is panchromatic, orthopanchromatic can also be useful with proper correction factor if it can still see the peak of each channel. For color separation the important thing is filters used, or the specific "color" of light for each channel. Even it is possible to use a narrow band for exposing each channel, because in fact the spectral information is reduced to 3 channels at taking time.
At the end what it is important to indirectly measure (in color separation) is the ammount of "silver exposure" that was in the negative layers before color developer, it is less interesting what spectral spread had the color dyes, comming from color clouds, as this can be reproduced again in a post process.
What I see in color separation is that we can make a separation that tries to preserve the particular film food print, or aiming the channel peak with a narrow spectral window, so we get something related to the silver content of each layer before color developer, then we can remove most of the film footprint from the result, and later we will be able to get any footprint if we want.
Anyway for color separation, IMHO, what is really important is filters for each channel, the filter selection may also consider the spectral sensitivity of the separation film...
A characteristic curve that was pretty much a straight line & the ability to raise & lower the contrast over a broad range were the two main attractions. TMY-II exposed off the toe can do the straight line thing pretty well, & there are solutions when you need to expand flat contrast situations - Super-XX was a good solution for its time, but suffered in the grain & resolution departments.
Karsh was all about lighting to a contrast range, not about mucking around with processing times & exposure - why bother if you can light to the 7-stop range of G2 paper? It's about tungsten fresnels, bounces, flags & playing the fall-off behaviour.
You have to remember that a lot of stuff printed via dye transfer was from (minimum) 4x5, a lot of it was from 5x7, 8x10 etc & rarely printed bigger than 20x24 (at least until relatively later in the dye transfer era) - in that context the grain of Super-XX was less of an issue & its contrast controllability (which controlled saturation) & colour sensitivity were far more important. Even a 3-4x off 8x10 starts to show visible grain - & preventing excessive graininess on 35mm dye transfers seems to have been one of the biggest debates in the dye transfer world. Right at the end of the dye transfer era, Kodak seems to have started to suggest TMX as a way to experiment with in-camera separations etc.
I'd also strongly suggest you view some dye transfers 'in the flesh' to experience & understand their distinctive characteristics.
And that's before we consider the dye transfer variant for making dyes from colour negs - but that was limited to maximum 16x20 prints I recall.
Finally, if you want to play with colour separation, apparently the #70, #98, #99 set offers the most accurate results.
Thanks for the info, I'm interested in experimenting triple color-filtered BW glass plate negative, I'll start with those wrattens you point. This is not separating colors from film, but from scene, but it should work close.
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