I have the Epson V700, which is rated to collect data at similar
densities.
I did a number of tests to compare actual acquired data between it and
the two film scanners I own, the Minolta Scan Dual II and Nikon
Coolscan IV ED. These are rated at 2820 and 2900 ppi respectively. I
found that the very best I can get out of the Epson V700 shows about
2600 ppi tops, more like 2400 ppi, where with the two film scanners
the actual resolution is very close to the rated data density,
probably at least 2800 ppi. I attribute this to a) no glass in the
light path and b) a focusing lens system on the film scanners.
The lower actuance and slight gaussian defocus evident with the
flatbed scanner has a minor side effect of softening dust and
scratches on film, which can sometimes be handy. The images sharpen up
nicely with Photoshop CS2's Smart Sharpen filter but that's not the
same as having more detail to work with.
So scanning at 4800 ppi with the flatbed scanner is pretty much a
waste of space in terms of actual data you'll acquire. I tried
oversampling on scan and downsampling as Paul suggested ... I saw no
difference in the end-product image quality scanning at maximum
interpolated resolution vs scanning at 3200 ppi, and the maximum took
four times as long and created needlessly enormous files to manage.
With either of the film scanners, I've been able to create excellent
B3 Super prints of full-frame 35mm scans. It's not easy ... you need
an excellent negative and careful attention to rendering to get around
the issues of grain and emulsion defects, but it's possible. 8x10 to
11x14 sized prints are certainly much easier to produce.
It's important to remember that creating an 11x14 print from a 35mm
negative is an 11x enlargement, at minimum, even optically in a
darkroom. Most film max'es out at around 15x enlargement for decent
quality. Adding the scanning process into the enlargement workflow
adds a few percentage points of additional losses but allows
appropriate digital image processing to help recover that, which can
add up to a plus IFF you know what you're doing with image processing/
rendering. "Better a clean and beautiful 5x7 than a lesser 10x15."
Making quality prints is much more than just counting pixels and
figuring dimensions ... !
Godfrey
On Mar 12, 2009, at 4:50 PM, Nick Wright wrote:
Really? Wow. I had no idea. I found some web site saying that would
just be enough for an 8x10, and I thought that's definitely more
resolution than "just" and 8x10. Didn't realize it was that much more.
Thanks.
On Thu, Mar 12, 2009 at 6:47 PM, John Francis <jo...@panix.com> wrote:
On Thu, Mar 12, 2009 at 06:31:38PM -0500, Nick Wright wrote:
Okay, one more scanner question.
The Epson v300 says that it scans 35mm film at 4800 dpi. What does
that equate to in terms of megapixels?
Well, a frame of 35mm film is 36 x 24 mm. At 25.4mm per inch, that's
(36/25.4)*4800 * (24/25.4)*4800 = near enough 30 megapixels.
That's 90MB at 24 bits/pixel, or a whopping 180MB at 48 bits per
pixel.
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