GSR - FR wrote:
Hi,
[EMAIL PROTECTED] (2006-03-19 at 2339.24 +0100):
Hi!
... and is there any difference in picture if I set:
100x100 in 400dpi
or
200x200 in 100dpi
and make a print from it (in same size - 10cm x 10cm for example)?
Then it is not 400 or 100 DPI, but (rounding to 1 inch = 2.5 cm) a 4
inch print, so you have printed 100 pixels to 4 inches and 200 to 4
inches too, so that was 25 and 50 DPI. Maybe you are confused with the
printer's DPI (300, 720, 1440...) but those are not pixels, but ink
dots. The print system has to convert the file/screen pixels (think
about them like squares or rectangles with different levels of
intensity) to ink dots which are on or off (one level of intensity, so
the printer creates patterns of dots to simulate the intensity levels
when looked from "far away").
I have been trying to understand this better myself. I couldn't find
any good
help on it. My goal was to determine the maximum size image in pixels
that would
print exactly on a letter-size paper with no scaling. I built a
resolution test image
and found that the highest resolution that I could see a 1 pixel line on
my printer
was about 150 pixel/inch. This is on windows xp. I see that in at
least some file
formats, the resolution setting is saved in the metadata as dpi. But
when I print the
image using different applications, I get different results. The apps
seem to use or
package the data differently for the driver. For example, one app has
options in
the print dialog for "fit pixels" "fit resolution" and "fit to page". I
haven't figured out
yet exactly what this does (other than fit to page obviously scales the
data up or down
as required.
My printer also has a poster mode (2x2, 3x3,4x4). As best I can determine
all this does is first scale the image to a single page in the app and then
the printer just zooms it (I don't know if it does any sort ot
interpolation but I doubt it).
scott s.
.
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