Printer/Scanner Specs

This question has been bugging me for ages and I haven't been able to
find anyone who has the answer!

When looking at the spec for printers or scanners, two different
resolutions are given (eg. 2880 x 1440dpi for an Epson Stylus 950P).
What does the other resultion refer to? In the example I know that the
actual max. resolution is 2880DPI, so what about the other? With
printers, the larger number is alway the first and with scanners, the
smaller number is always first. It isn't anything to do with
interpolation features, and it doesn't seem consistent with the min
max resolutions or something similar. Occasionally the 2 numbers are
the same, sometimes a factor or 2, 4 or 8 different. It cannot be
anything to do with X versus Y DPIs since the variety or differences
points away from this and the fact that the number size is reversed
with scanners.

Can anyone put me out of my misery?

Thanks,

Michael.

Michael wrote:

This question has been bugging me for ages and I haven't been able to
find anyone who has the answer!

When looking at the spec for printers or scanners, two different
resolutions are given (eg. 2880 x 1440dpi for an Epson Stylus 950P).
What does the other resultion refer to? In the example I know that the
actual max. resolution is 2880DPI, so what about the other? With
printers, the larger number is alway the first and with scanners, the
smaller number is always first. It isn't anything to do with
interpolation features, and it doesn't seem consistent with the min
max resolutions or something similar. Occasionally the 2 numbers are
the same, sometimes a factor or 2, 4 or 8 different. It cannot be
anything to do with X versus Y DPIs since the variety or differences
points away from this and the fact that the number size is reversed
with scanners.

Can anyone put me out of my misery?

Thanks,

Michael.

For most printers, the first number is the horizontal 'equivalent'
resolution; for color printers, this is often the actual resolution
times the number of colors. The second should be the lines per inch the
printer can step the page under the print head, which may represent
steps smaller than the smallest dot from the print head, and can be a
good way to enhance apparent sharpness.
For scanners, the first number is the maximum horizontal resolution the
scanner may achieve, possibly including interpolation to simulate higher
than physical resolution of the scan head. The second number is the
number of steps the scan head can make, which is often two or more steps
per pixel width, and is similar the the same number for printers.
As you said, none of these numbers may represent the actual resolution;
they are labels to entice potential buyers to the highest numbers, real
or not.

Michael wrote:

For most printers, the first number is the horizontal 'equivalent'
resolution; for color printers, this is often the actual resolution
times the number of colors. The second should be the lines per inch the
printer can step the page under the print head, which may represent
steps smaller than the smallest dot from the print head, and can be a
good way to enhance apparent sharpness.
For scanners, the first number is the maximum horizontal resolution the
scanner may achieve, possibly including interpolation to simulate higher
than physical resolution of the scan head. The second number is the
number of steps the scan head can make, which is often two or more steps
per pixel width, and is similar the the same number for printers.
As you said, none of these numbers may represent the actual resolution;
they are labels to entice potential buyers to the highest numbers, real
or not.


Thanks for the info: Since the larger of the two numbers always seems
to be the maximum resultion setable on the device to print or scan,
are you saying that is value is not the actual value being used by the
device and that we are being mislead (certainly with scanners I've
used, the interpolation value is always higher than either of the X x
Y values on the box and so neither of these values refers to the
interpolation value).

Michael.

What I'm saying is that the device can physically advance at the higher
number, so the specs aren't technically untrue, but, especially in the
case of a scanner, the higher setting may not provide any practical
value. These values are certainly intended to mislead (as all
advertising is at one level or another). That's advertising.