The
collapse of prices of midrange flatbed scanners has now placed 1200
dpi flatbed scanner quality within reach
of even SOHO and desktop publishing budgets.
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35mm
slide scanner close up
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Why
do you need 4000 dpi for a 35mm film scanner when
flatbed scanners are 600 dpi, 1000 dpi, or
1200 dpi only? Mathematical simplicity, a 35mm slide offers
a tiny surface. To expand something that small large enough to print
on 11 x 17 full bleed or wide format (24", 36",
up to 60" or more) then you need all 4000 dpi. In fact
we do not review any 35mm slide scanner at under 2700 dpi (1800
dpi is adequate for the Internet but not for color printing).
Actually,
at 4000 dpi you can get better results from your 35mm slide
than you can with a medium format transparency taken with a Hasselblad.
This is because to scan your Hasselblad transparency you (will most
likely) have to use a flatbed which is probably limited to a meager
600 dpi or 1000 dpi. Our bare minimum that we recommend is 1200
dpi. To get 4000 dpi on a medium format transparency you need an
Imacon (vertical) scanner or a top-of-the-line flatbed such as the
Fuji
C-550 Lanovia, ScanView,
or Heidelberg
Prepress solution
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| 35mm
film scanner |
What
if you have thousands of 35mm slides to scan? People
who have tons of slides to scan usually go out and buy a simple scanner
with an auto-feed system (such as available for the various Nikon
scanners). But this is not really an effective manner of scanning
35mm slides if you have several thousand.
If
you have an entire lifetime of 35mm slides, you need a tabloid-sized
flatbed that can handle a minimum of 40 slides at a time. You can
keep them in the mounts. Sophisticated flatbed scanners such
as the Scitex give their full optical dpi across the entire
bed.
This
is the only kind of flatbed that you can use for filling all the
space up with slides. Because with cheaper scanners, you do not
get the advertised dpi at the edges (you only get the full dpi down
a narrow strip, the so-called "sweet spot."). So check
out www.scitex.com. Their new model, the Jazz (EverSmart Jazz) drops
the entry-level price for Scitex quality. If you are scanning for
publication, you will probably want one of the higher-end EverSmart
models such as the Pro II, for example.
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Scitex
slide scanner
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You
will be happy to learn, however, that the dpi of the surface of your
scan is not what is required for the dpi of your printer. Your printer
will probably calculate what it needs based on lpi (lines
per inch). For the 1200 dpi QMS laser printer, the maximum it can
absorb is 280 dpi per surface unit. The usual formula is around 1.5
times the lpi. The QMS operates at a lpi of about 90, so 135 dpi per
surface unit ought to be enough. At a certain point excess dpi is
thrown away by the printer. At a higher point, the dpi chokes the
PostScript interpreter and your printer grinds to a halt (it simply
crashes). The FLAAR test center can get away with excess dpi because
the test system has 800 MB RAM; the test printer has 112 MB RAM; and
the hard disks are 10,000 rpm Seagate Cheetahs as a Level 0 RAID array
for added speed.
Also,
our digital camera can take individual photographs at 350
MB and above, so we have plenty of extra dpi to spare. But it is
simple enough for you to test what the limits are for your printer.
Another
example, The Center for Advanced Imaging in St Louis estimated that
their 600 dpi HP 3500 wide format printer needed only 120 dpi per
surface unit. I fed it 175 dpi and it accepted that. All this means
that a 35mm slide scanner such as the 2700 dpi Nikon CoolScan is
just fine for most uses, unless you need to enlarge a smaller detail
portion of a 35mm slide. Then you need to upgrade to the Polaroid
SprintScan 4000. 35mm film scanner. Of course "film
scanner" and "slide scanner" are all the
same piece of equipment. You can feed them a film strip or a single
slide still in its mount.
If
you are going to feed your slide scanner (or flatbed scanner) 35mm
color negatives, then you have a color cast situation that requires
extra patience and some professional software. Better search the
book shelves to find the ideal solution. We welcome feedback from
people who have solved the problem of scanning color negatives,
since we use only color positives (transparencies, slides) in our
photo studio.
There
are plenty of books
which give a more thorough and technical explanation (several of
our web sites have sections on Book
Reviews). Other users have their own formulas. I can just report
what we have found in our own three years of testing. Do not feed
your printer too much dpi or it will get indigestion, but if you
skimp and have too few dpi, the quality of your picture will be
lessened.
In
most cases it is probably easier to get both a flatbed and a slide
scanner (unless you can afford an Imacon, in which case you do not
need a separate 35mm film scanner since the Imacon can handle 35mm
up to 4x5 formats). Be sure to check out the many other pages of
reviews, so that you can avoid the several 4x5 scanners which
are overpriced (and inadequate) when compared to other possibilities
that perhaps you were not aware of.
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FLAAR offers for you more information about this subject |
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