I acquired epson v700 scanner for 4 years and had tried many times, still could not have a good scan. sharp focus scan is already very difficult to achieve. And it is more difficult to deal with high contrast positive. The dark area of positive is almost block in the scanned file.
What resolution are you scanning at? You cannot possibly get sharp pictures at the resolutions advertised by the manufacturers. They are liars. The highest resolutions where you can get reasonable sharpness range from 1800 to 2400ppi. But it is still useful to scan at 4800 or 6400 ppi, as you are oversampling. You can downsample afterward and you then have an image with far less scan noise. Even then, you must sharpen liberally. You might also want to try different height settings on the film holder to try to achieve optimal focus. Further, put your scanner on a very solid surface, maybe the floor, as vibrations in the scanner also reduce resolution. My scans with my V750 are much worse if the scanner is on a wobbly, light table.
As far as the dark areas of slide film go, yes, this is a problem with these scanners. Velvia 50 is especially problematic. You can try using the multisampling and multi-exposure features of the scanning software. But they don't help much. With these scanners, you can only get about 4 stops of DR out of Velvia 50. A drum scan will get you more. With negative films, your scanner should easily capture the full range. I haven't tried Provia, Astia, or Velvia 100. Supposedly they are a little better than Velvia 50.
I've gotten sharp image at 3200 and discover its mostly impossible without the aid of the betterscanning adjustable height holders AND the ANR glass.Originally Posted by oysteroid
With the Epson holders, 1 they don't hold the film flat so the focus on the edges is better but the center is off, and 2 the holders themselves don't hold the film at the proper height and are actually at a hyperfocal distance so it's impossible to get a clear scan film them.
My only suggestion is, I only own the betterscanning holders for 120, so for 35mm, I take the film and place it on the Epson wet scanning glass that comes with the scanner then I take the 120 ANR glass and lay it on top, the height of the wet scanning glass seems to be about right, sometimes with curly 35mm I need two pieces of ANR on top of each other.
Anyway hope that helps, it's not that the scanner is incapable, just that the scanner's lens distance isn't really at the sweet spot so it takes some adjusting of the height of the film and making sure to keep it flat to get it just right.
StoneNYC,
I have adjusted the holder in very small increments using paper shims, looking at only one tiny spot, and moved through a range, making sure I went from unfocused to ideally focused to unfocused again, then returning to the most focused height to make sure I was at the ideal height. Then I tested various resolutions. Realistically, on my scanner, I don't have good sharpness above 2400ppi, and that's pushing it. More realistically, it is like 2100 or so. And tests by many others seem similar to my results. If you are able to get 3200, you must have a better example of the scanner than I have. But I would be very interested in seeing a full resolution crop of what you consider to be sharp output at 3200ppi.
Sure ill try and crop it out in the next few days, I had a great example but deleted the fuzzy one, wish I kept it.
It's taken me a long time of perseverance and each type of film is different. If I don't post in a few days send me a reminder.
I did some tests using a standard chrome on glass resolution mask a while back with my V750.
The target I used was chrome on glass with a 16 X 16 arrayed set of 2540 X 2540 µm sized targets. The plate was sloped (wedged) from 0 to about 4mm in order to capture the point of best focus. I did three scans at 1800 spi, 2400 spi and 4800 spi.
The scans were measured at three cell line pairs for resolution and contrast using the difference divided by the sum method with photoshop K values converted to an 8 bit scale. A bit tedious to do this so I picked line pairs that would give reasonable data at the low and high bit ends. Summary below after checking this older data again.
SCAN / CELL ID / lp/mm / CONTRAST vertical / CONTRAST horizontal
1800 spi / 1-1 / 20 / 39% / 39%
2400 spi / 1-6 / 40 / 28% / 24%
4800 spi / 2-1 / 42 / 52% / 45%
The 1800 spi data is considerably inferior to the 2400 and 4800 data while there is a gain in contrast at 4800 spi over 2400. This is not inconsistent with what people have seen previously, although I was a bit surprised at the better contrast at close to the same lp/mm using 4800 over 2400.
Nate Potter Austin TX.
Last edited by Nathan Potter; 11-Feb-2013 at 19:58. Reason: Well the software doesn't like my spacing so I'll try a marker to separate.
I don't understand most of what you said honestly, but I believe that you discovered the V750 is capable if 4800 with good contrast/sharpness? And that the 1200 was actually somehow worse?
Can you explain this in "for dummies" terms?
Nathan, thanks for the test, its interesting, however i dont get this - if contrasts on 2400 are worse than on 1800/4500 how is 1800 is inferior? Also, one more thing - which lens array you used? One for 8x10 or smaller one?
StoneNYC, sorry for too much tecno babble. I forget that many are just not used to resolution measurements. I did three scans on the Epson V750 using the glass resolution mask pictured below.
One each at 1800, 2400 and 4800 samples per inch using the high resolution lens.
TOPPANmsk-2 by hypolimnas, on Flickr
The arrayed mask of 16 X 16 identical cells allowed me to slope the mask on the Epson using shims. That common technique is used to capture the point of best focus somewhere along the mask so that these cells then can be used for focus accurate resolution measurements. Since the Epson is an all digital capture device the most convenient way to measure the contrast between light line areas and dark line areas is to use photoshop eyedropper K % values. I'm interested in doing this measurement over the full density region that can be captured by the Epson so I try not to use any contrast enhancement and no sharpening in PS. I scan the eye dropper over the pairs of lines available and average the light and dark readings. For example I may have a string of readings; 70-1-53-6-58-0-70-1-43; a pretty noisy set so I may take more than one set for each line pair both horizontal and vertical. Lastly I apply Korens' (and others) method to determine the absolute contrast ratio between dark line and light lines.
The idea here is that we want to find the maximum Line Pairs / mm. that also yield a decent contrast value. A sort of standard contrast used by many is 50%. In digital print quality as well as all analog technique the human eye is very sensitive to contrast in an image so a full disclosure of scanner quality really needs both linewidth and contrast data to be truly quantitative.
Notice for this exercise I tried to guess ahead of time which lwpairs would yield about 50% contrast but failed to get it quite right. The scan at 1800 spi produced a pretty inferior image at best focus so I had to choose the 20 lp/mm pair to obtain 39% contrast. As I mentioned above both the 2400 and 4800 scans showed a notable difference in contrast at nearly similar lp/mm of around 40.
Now this kind of exercise may not tell you much about the actual reproduction quality of a film (especially color film) on the Epson. This is simply a quantitative comparison technique. For instance it appears there is a slight advantage in resolution and contrast using 4800 spi vs 2400 spi.
Nate Potter, Austin TX.
SergeiR, for the 1800 scan I needed to go down to pairs 1-1 (20 lp/mm) in order to get a 39% contrast while 2400 and 4800 yielded reasonably useable contrast at around 40 lp/mm. Used higher resolution lens array.
Nate Potter, Austin TX.
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