Or in the case of scanning, moving the negative by exactly 0.5 pixels. It seems like, in order to achieve real resolution increases, you would want to move the camera 0.5 pixels in between photos (like how the Sinar and Olympus systems move the sensor). The results are explained here (text is in French but the scans of the target are visible images with no language barrier ) ) I have no clue for this, except that the precision of the mechanical stage in the EPSON flatbed is probably not sufficient to allow the half-pixel sampling procedure with a good precision. worse in the direction of the mechanical scan, exactly the opposite of what should be expected. One of the readers of the French MF+LF forum has tested a brand-new Epson 850 flatbed with an USAF 1951 target (both the Silverfast on silver halide film, plus another from Edmund Optics, chromium on glass) and has found the effective resolution to be. In principe, flatbed scanners can scan with double (or even more) sampling rate in the direction of the mechanical translation, hence in principle improving resolution by the theoretical factor 2, in one direction only. 4 passes combined together make the 2 samples per pixel size in both directions and allow to extract the whole theoretical resolution of an analogue image blurred by averaging through a square slit. In the Sinar system, the whole pixel grid can be shifted by 1/2 pixel size in both directions i.e. Digitizing requires two samples per cut-off period, hence two samples per square size in both directions are required to extract all what is contained in the averaged image.Īn hypothetical scanner with adjacent square pixels can only digitize with one sample per pixel size. When analyzing an analogue image through a square slit, the blur induced by averaging the densities through this slit roughly corresponds to a cut-off period which is equal to the square size. The rationale behind the Sinar scanning system is something very simple. It looks a little easier to use, and more for the intended purpose, than Deep Sky Stacker.įinally, you can do it in Photoshop with this tutorial, only published a few days ago: It is windows only.Īlso found Chasys Draw IES can do it, as described here: It is also free and can be downloaded here: It is windows only. ![]() There is a free trial version as well.Īlso found that Deep Sky Stacker can do it, using the NASA Drizzle algorithm (yes that's what it's called): Deep Sky Stacker is free. ![]() It looks very fully featured, but is $150 for the full version. The main one is PhotoAcute ( ) which is available for windows and mac. There is some software for this with digital capture (should work with scans too i think), but I don't remember the name of it. I edited my post to make that more clear. Rotating it might get a better result, in theory. The above examples are (as far as I can tell) just moving the slide on the scanner bed. ![]() If I was going to do this myself, I would try Will's advice and do four scans, one with the negative rotated 90 degrees each time, to change how the scanner light hit the dots on the negative. The lower left is three scans merged, and the lower right is four scans, merged. Here is pretty clear evidence that this can work: The upper left is one scan. In this thread there is some evidence that merging multiple scans of the same negative, with the negative shifted on the flatbed each time it is scanned, can be merged and increase the total resolution. If you want to do this with a scan of a negative, supposedly it CAN be done. It's like doing panoramic stitching, but the images are 99% overlapped. Then the camera merges the images together to form a higher-resolution file. So each image is very, very slightly from a different angle. It takes a series of images and moves the sensor in the camera around a tiny amount before each image. It's just like doing it with the "new" Olympus technology (available in Sinar digital backs for many years) to generate 40?MP files with a 16MP sensor. With Photoshop's "Auto-Align Layers" tool it would be easy to align multiple images, and then use an HDR plugin (or Photoshop's native HDR tools) to merge the layers to create the final image.Īs Will says, if you want to do it to increase resolution, the images (or the scans) have to be different in some way. So it can be done for increased dynamic range. ![]() In this thread: Tim Parkin mentions doing two scans of one negative with different settings, effectively scanning the shadows in one and the highlights in another, and then merging the two images in photoshop to create a high-dynamic-range image.
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