Scans, Scanning and Digital Files.
What is a digital image file?
A digital image file is a file used by a computer to recognize,
display and use an image. Your computer may have more than
one program capable of interpreting and displaying digital
image files. Adobe Photoshop is the most widely utilized program
in the graphics, photographic and printing industry used to
display, adjust and save digital image files.
Where do digital image files come from?
Digital image files can be produced from a photograph or
a piece of artwork using a scanner or created directly with
a digital camera.
What is a scan?
A scan is a digital image file produced by a scanner from
photographic film or artwork. A scanner detects the varying
amounts of red, green and blue (RGB) light transmitted through
or reflected from the photograph or artwork and records that
information as a digital file. Your computer then reads that
information and tells your computer monitor to display those
amounts of red, green and blue light to create an image on
your monitor.
When a printing company scans your photographs they also
convert the RGB colors into cyan, magenta, yellow and black
(CMYK). These four colors relate to the four printing inks
used in a traditional printing press. The conversion from
RGB to CMYK usually occurs "on the fly" or during
the scanning process. For more information about CMYK files
and printing color click here.
A computer can display images in both RGB and CMYK format.
Desktop printers print RGB files and all images used on the
internet are usually RGB files. CMYK files are used in traditional
printing press work.
What is the difference between a scan and a digital file
made by a digital camera?
A digital camera records the red, green and blue light striking
the sensor and records that as a digital image file. A camera
using film does a similar job but the record of the light
is stored by a piece of film using dyes.
In order for a computer to use a photograph captured on film
the information on the film must be converted into a digital
record via the scanning process. A digital camera skips the
film and scanning steps, creating a digital file directly
from the light striking the camera's sensor.
What are the advantages of film vs digital image capture?
Film:
Pros: Film produces a photograph with many
more colors than a digital camera can capture. You also do
not need a computer or other piece of hardware to view a photograph.
Cons: Film is expensive to produce. It also
needs to be scanned in order to be used on a computer and
printing press which takes time, costs money, reduces the
sharpness of the image as it passes through another optical
process and reduces the number of colors down to the same
(or similar) as a digital camera. Film images contain "grain"
which can be visible when enlarged.
Digital Camera:
Pros: A digital file does not need to be
scanned in order to be used in the printing process therefore
does not suffer loss of sharpness or detail that is inherent
in converting an image from film into a digital file. After
the initial purchase of the camera, ongoing images cost almost
nothing to produce. Images can be viewed, transmitted and
used immediately. No grain.
Cons: Digital cameras currently produce
files much smaller than those that can be made via the film
scanning process.
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