|
Although the digital camera and computer
are transforming photography, for the home
practitioner, a quality image is still best
captured with the traditional camera. Even the
smallest photographic negative (or slide) contains
more information than current consumer
digital devices can capture. Opto-chemical
photography is still alive and well! BUT NOT FOR
LONG!
a bit
about Scanners
All scanners have a maximum OPTICAL scanning resolution which
limits the data that can be read from the source.
Most scanners also have software which can
interpolate to much higher resolutions, a process
which Photoshop can also do for you. Remember that
interpolation means "creating" a NEW value between two known
values. This process DOES NOT ADD
REAL DATA, merely "fills in gaps" (see the
example in "Scan the Negative, or
a Print?" below.
Highly sophisticated "high-end" software can
produce miracles, so you need to experiment with
yours.
Remember that every time you adjust the SIZE of the file after scanning,
you force the software to recalculate the values of
the pixels and thus compromise the integrity of the
image by DISCARDING or ADDING data.
|
TRANSMISSION (Slide
or Negative)
Scanner
As discussed elsewhere, a pixel density of
300 per inch is adequate for most printing
applications. The latest round of scanners
of this type scans at 4,000 samples per
inch, up from 2,700. The light source can
be such that grain and all defects are
rendered accurately - somewhat analogous
to "point source" or "condenser"
enlargers. Compare with "REFLECTIVE Scanner with a Transparency
Adapter" described below.
|
|
REFLECTIVE (Flatbed)
Scanner
An inexpensive 600 pixel per inch flatbed
scanner can provide enough information for
a print twice the size of the original. It
is possible to get stunning 10 x 15 inch
ePixel prints from 6 x 8 inch fine B&W silver prints
made from Minox negatives. The latest
round of flatbed scanners in the $400
range can sample at rates as high as 2,400
per inch.
|
|
REFLECTIVE Scanner
with a Transparency
Adapter.
Transparency adapters have always been
available for flatbed scanners. Usually
consisting of a light bar in the optional
lid, they provided a "point source" type
of illumination, which coupled with the
relatively low pixel count, made them of
marginal use for other than proofing. The
introduction of the $400 Epson
Perfection 2450, a 2,400 sample
per inch flatbed scanner with a diffuse
light source in the lid is producing scans
which can be printed at 8 times the
negative size while maintaining the
nominal 300 pixel per inch density needed
for quality printing. The diffuse light
source minimizes grain and provides
quality images from both 120 and 4x5
negatives. It is entirely possible that
for these larger negatives, scanning the
negative is now preferable.
|
Scan a Negative,
or a
Print?
Density Range &
Curve
Scanning
in Color or
B&W
|