Peter Figen
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Yes, Ektar is the sharpest color neg film I've seen. The current Ektar 100 doesn't seem quite like the old Ektar 25, but it's still very sharp. You can scan it with a 6 micron aperture, but Portra 160 is just not in the same league. You have to use a 16-19 micron aperture for optimal scanning. Personally I like the look of Portra over Ektar even though it's softer. The Ektar is has more contrast as well.
For those who don't know, when you are drum scanning, there are two factors that determine the resolution of the scan. One is how fast the lead screw moves the drum past the lens as the drum is spinning. That, in effect, determines how many "slices" the scanner sees from one end of the frame to the other. The other, which I've alluded to above, is the size of the "spot" that the scanner lens sees as the drum spins past. There's typically an aluminum disk behind the lens with a series of holes, measured in microns, that tell the scanner how wide of a slice to look at during the scan. Those apertures, which aren't really like the lens apertures we know and love, are used to determine the overall resolution. For instance, when you set the drum scanner to 4000 dpi, it sets the aperture to 6.35 microns. Multiply 6.35 microns time 4000 and you get 25.4 mm, which we all know, is one inch, or 4000 spots per inch.
All of this aperture and micron size is important because it also relates to grain size in the film. If you match the aperture size to the grain size you will get the optimum combination of detail without overemphasizing grain. If you use a smaller aperture and higher resolution, the grain on color negs will be overemphasized and you'll get scans that look too grainy. You can decouple the aperture setting from the resolution setting and choose a larger aperture that more closely matches the grain of the film. In testing we did years ago, scanning 4x5 color negs, we were able to exactly match a projected print, make a scan that had slightly smoother grain and a tick less detail, or go the other way and have a scan that was slightly sharper than the projected print but with a bit more grain. At that point it becomes a subjective decision. But the main point is that by manipulating the scanner hardware, you can get the best quality scan possible. Color negs are also problematic because they have limited density in the neg itself and are quite flat. This is a great match for printing paper but tend to emphasize the grain with the image is inverted and the contrast is optimized.
It's late here and I hope this makes sense. Too many drum scanner operators don't know how to optimize for different films and it's simply not possible on any other type of scanner, but often doesn't matter as low end scanners usually have limited resolution.
But to put some of this in perspective, if your film scans optimally at 16 microns, that's the equivalent of 1600 dpi. If it scans best at 12.7 microns, that's the equivalent of 2000 dpi, no matter how many pixels you're asking the scanning to produce.
Peter
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