HP color laserjet 4500 Manuale Utente
EN
Image formation troubleshooting 159
9
Common causes of color variation
The following list outlines the major causes of color variations between
computers, applications, and output devices.
computers, applications, and output devices.
•
Halftone patterns produced on monitors and the types of patterns
used in the print jobs are different and might cause variations in the
printed output.
used in the print jobs are different and might cause variations in the
printed output.
•
The printed output differs from the image on the monitor because
the monitor and the print media have different reference values of
black and white. The monitor screen has charcoal gray for the black
level, and the white on the monitor screen is actually blue. Black on
the print media is limited only by the fill capability of the printer, and
most good quality paper has a very high white level. In addition,
phosphor (used in color monitors) and toner have entirely different
spectra characteristics and different color-rendering capabilities.
Differences between output are common. Blues generally match
better than reds.
the monitor and the print media have different reference values of
black and white. The monitor screen has charcoal gray for the black
level, and the white on the monitor screen is actually blue. Black on
the print media is limited only by the fill capability of the printer, and
most good quality paper has a very high white level. In addition,
phosphor (used in color monitors) and toner have entirely different
spectra characteristics and different color-rendering capabilities.
Differences between output are common. Blues generally match
better than reds.
•
The color of the ambient light changes the perception of color.
Fluorescent light lacks many colors present in incandescent light,
and the color range of natural light is broader than any artificial light.
When comparing color, choose a standard light source for reference
and understand that the perceived color will change as the light
changes.
Fluorescent light lacks many colors present in incandescent light,
and the color range of natural light is broader than any artificial light.
When comparing color, choose a standard light source for reference
and understand that the perceived color will change as the light
changes.
•
Long-term color variations occur as paper ages. Use high-quality
paper and protect the paper from sunlight to help minimize
discoloration.
paper and protect the paper from sunlight to help minimize
discoloration.
•
Environmental changes can cause color variation. The development
process places a high potential across an air gap to attract toner to
the imaging drum. Changes in relative humidity vary the point at
which the toner travels to the imaging drum.
process places a high potential across an air gap to attract toner to
the imaging drum. Changes in relative humidity vary the point at
which the toner travels to the imaging drum.
•
All consumable components have a finite life span, and as these
components reach the end of their useful life, their ability to produce
consistent print quality diminishes.
components reach the end of their useful life, their ability to produce
consistent print quality diminishes.
•
Paper roughness can cause colors to look different. Use standard
paper.
paper.