At 01:37 PM 3/25/2004 -0600, you wrote:
I'm a bit perplexed at what the dpi means on a film scanner. Trying to
compare apples to apples, will a 4000 dpi Brand X film scanner in theory
produce a better quality image outputted than a 2000 dpi Brand X scanner,
given that the output resolution is the
If I understand what you are saying, I think that I cannot agree with your
explanation. Your analogy appears to be confounding halftone dots with
halftone cells. Moreover, it is not necessarily the case that either
translate one-to-one into pixels or into samples. Also I believe that if
your
Always appreciate your butting in and corrections. :-) If your remarks are
based on the paragraph quoted alone, I will defend myself by noting that I
was only extrapolating from the orgianal statement of the analogy by the
preious poster using their language and argument structure.
If you are
Hi Laurie,
Always appreciate your butting in and corrections. :-)
You are too kind ;-)
If your
remarks are
based on the paragraph quoted alone, I will defend myself by noting that I
was only extrapolating from the original statement of the analogy by the
previous poster using their
Laurie Solomon wrote:
I think that he was asking more about if this causes an increase in the
image size and not the file size; but I could be wrong.
Yes I was talking about image size. All I really wanted to know was if a
4000ppi scanner was capable of producing a better outputted image
Image quality is a multi-faceted subjective thing that cannot be measured in
quantitative terms which is why it is never refered to on spec sheets.
Obviously a optical 4000spi scanner will be sharper and have higher
resoution than a scanner that is capable of only optical resolutions of less
than
Better is a relative term. Generally higher dpi (technically it should be
spi or samples per inch and not either dpi, dots per inch, or ppi, pixels
per inch) will produce a higher resolution and sharper image than lower
amounts of samples per inch. One has to be careful in making comparisons
Most color film scanners use a CCD chip which has a series of three
lines across it each with a color filter over it, Red, Green or Blue,
which each are made up of a series of sensors. (Nikon uses a slightly
different method, but I don't want to confuse things).
That line contains a specific
Art,
That line contains a specific number of sensors across it. For
simplicity, let's assume a film frame is one inch across by 1.5 wide.
That would mean if the scanner claimed a 4000 dpi (really ppi or pixels
per inch) resolution, the image dimensions when a file was created would
be 6000
Art,
I really am not trying to pick on you (ok, yes I am); scanners techically
measure resolution in terms of samples per inch or spi. Thus, Your
correction below is wrong.
That would mean if the scanner claimed a 4000 dpi (really ppi or
pixels per inch) resolution
It is really 4000 spi and
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