Oki ES3640eMFP Reference Manual page 106

A
A-106 Desktop Color Primer
Beyond a certain threshold, a higher image resolution greatly
increases file size while having a minimal effect on output quality.
The optimal image resolution depends on the resolution of the
final print device. Aim for the resolution that optimizes both file
size and output quality.
The resolution of a raster image, along with its bit depth and
physical dimensions, determine its file size. The following table
shows the file sizes of color raster images at different dimensions
and resolutions.
Image size 100 ppi
RGB/
CMYK
x 0.4/0.5 MB
3" 4"
x 1.0/1.3 MB
5" 7"
x 2.7/3.6 MB
8.5" 11"
11" x 17" 5.4/7.1 MB
In this table, the shaded areas indicate that 200 ppi is typically
the best trade-off between image quality and file size. However,
higher resolutions (for example, 250 to 300 ppi) may be
necessary for offset printing, when quality is of the utmost
importance, or for images containing sharp diagonal lines.
To find the best image resolution for your purposes, make test
prints of some raster artwork at different resolutions. Start with a
high-resolution image (400 ppi) and save versions at
progressively lower resolutions, down to 100 ppi, using a pixel-
editing application, such as Photoshop. Always save a copy of the
ES3640e MFP Color Reference Guide - 106
File size at
150 ppi 200 ppi
RGB/
RGB/CMYK
CMYK
0.8/1.0 MB 1.4/1.8 MB
2.3/3.0 MB 4.0/5.3 MB
6.0/8.0 MB 10.7/14.3
MB
12.0/16.1 21.4/28.5
MB MB
400 ppi 600 ppi
RGB/CMYK RGB/CMYK
5.5/7.3 MB 12.4/16.5 MB
16.0/21.4 36.1/48.1 MB
MB
42.8/57.1 96.4/128.5
MB MB
85.6/114.1 192.7/256.9
MB MB