Archived from groups: comp.periphs.printers (
More info?)
Hi George,
Let me try to help. This is a very commonly confusing aspect of printing.
The resolution indicated by an inkjet printer manufacturer is the number
of dots that can be addressed by head position. Often these are made by
using a variety of nozzles or overprinting via several swipes of the head.
That number is speaking about one ink dot (dots per inch). However,
inkjet printers create the hundreds of thousands of colors they can
represent by using a randomized mix of dots of the different colored
inks they have in the cartridges. That used to be simple (four colors,
CMYK). Today there are printers with extra colors and lighter and
darker inks included, but the principle is still the same, to create
photographic color you need many more colors than the inks themselves
can produce. In order to accomplish this, the printer uses different
percentages of dots of different colors to represent a color. Since the
dots are so small and packed so closely, to the human eye they appears
as a section of solid color, when actually made up of many dots of
several colors.
A certain shade may require a matrix of 9 or even more dots to create
the illusion of one pixel color from your monitor screen.
The average drug store variety photo print (4" x 6") has the equivalent
of about 200 dpi of resolution. A custom photo print may be 250-300 dpi
equivalent resolution.
Most printer manufacturers suggest something between 240-360 dpi as a
source file at final print size. So an 8" x 10" print should probably
have a pixel dimension something between 1920 x 2400 and 2880 x 3600
pixels. With a good printer driver and careful use of unsharp masking
even a 150-200 dpi source file can produce a decent result, especially
if it will be viewed at several feet away.
The best approach is to experiment and find the sweet spot for your
application and equipment. In terms of what printing resolution mode to
use, it depends upon the paper and inks you use, and the subject matter
of the image, but you will probably find that the improvement once you
get to 1200 or 1440 dpi, is not noticeably improved by going higher, yet
the printing time becomes considerably longer.
Art
George wrote:
> Hi all I am confused.
>
> I am happy with DPI, pixels and so on.
>
> However can someone explaing the following.
>
> 1. My printer has a max resolution of 1440 dpi.
>
> If I have a digital image of 2880 x 1500, it must only be 2 inches wide when
> printed at highest res.
>
> 2. Why do they say that 300dpi gives a good quality photo print, if my
> resolution was 2400 pixels wide, it would be only 8 inches wide, yet all the
> magazines say that this will give me decent a3 print.
>
> HELP!!!
>
>
Facebook
Twitter
Instagram