Is Arista EDU Ultra 400 the same as Tri-X 400, and how should it be rated in Diafine?
Asked 6/22/2014
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I’ve heard Arista EDU Ultra 400 was once considered similar to Kodak Tri-X 400, at least in 35mm, but that may no longer be true. Is EDU Ultra 400 actually the Tri-X-like stock, or is that Arista Premium 400 instead? Also, if shooting EDU Ultra 400 and developing in Diafine, what effective speed should I expect to use?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
12y ago
2 Answers
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Arista Premium 400 (135 only) is like Tri-X; EDU Ultra 400 never was. But if you're shooting anything other than 35mm, Premium isn't an option.
Ultra shoots at about 160 to 200 for moderate contrast (you'd need to pull it further if you're used to underrating Tri-X), so calling it a 400-speed film is a little optimistic.
It gets into reciprocity failure fairly early if you need to use slow shutter speeds (you don't have to get near Bulb; 1 second will need compensation). That may or may not be a problem for you, or a problem at all if you can afford to burn a couple of rolls and some chemistry to lay out a rough compensation curve.
It hates some developers, particularly HC100. It seems to love pyro and Xtol, but I know that pyro can be a problem for some people, so you'd need to take that into account.
EDU Ultra 400 isn't a bad film (in fact, the tonality and grain can be quite nice once you figure it out) it's just not what it says on the box at all.
Originally by user28116. Source · Licensed CC BY-SA 4.0
user28116
12y ago
0
Generated from our catalog & community — verify before relying on it.
According to the community responses, Arista EDU Ultra 400 is not the Tri-X-like film. The closer match to Tri-X is Arista Premium 400, and only in 35mm.
For Arista EDU Ultra 400, a practical working speed is closer to ISO 160–200 for moderate contrast rather than a true 400-speed rating. If you’re used to rating Tri-X lower than box speed, you may need to pull it even further with EDU Ultra.
Other notes from the answers: EDU Ultra 400 shows reciprocity failure fairly early, so exposures around 1 second may already need compensation. It also appears to be picky about developers—reported as disliking HC-110-type developers, while working better with Xtol or pyro.
Since no one provided a tested Diafine-specific EI, the safest conclusion is that you should not assume Tri-X behavior or a full EI 400. Start around EI 160 or 200 and test from there with your own workflow.
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AI12y ago
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