Canon ColorPASS-Z5000, Color Manual

Page: 28 / 214

1
1-12 ColorPASS Color Management
Black Overprint
The Black Overprint option lets you specify whether or not black text, defined as
RGB = 0, 0, 0, or as CMYK = 0%, 0%, 0%, 100%, overprints colored backgrounds.
•
On
—Black text overprints colored backgrounds, eliminating white gaps and
reducing halo effects or misregistration of colors. Setting Black Overprint to On
automatically activates the Pure Black Text/Graphics option.
•
Off
—Black text knocks out colored backgrounds.
N
OTE
:
PostScript applications may perform their own black overprint conversions
before sending the print job to the ColorPASS.
One example of how you might use this setting is with a page that contains some black
text on a light blue background. The background blue color is CMYK = 40%, 30%,
0%, 0% and the black text is CMYK = 0%, 0%, 0%, 100%.
• With Black Overprint On, the final text portions of the page are overprinted, or
combined with the underlying colors. This results in CMYK = 40%, 30%, 0%,
100% for the color used for the text. There is no transition in the cyan and magenta
toners, and the quality of the output is improved since it will not show artifacts near
the edges of the text. The option also works with text defined in the RGB color
space, that is RGB = 0, 0, 0.
• With Black Overprint Off, the border of the text is on an edge that has cyan and
magenta toners on one side (outside the text) and black toner on the other side
(inside the text). On many devices, this transition causes visible artifacts because of
the practical limitations of the copier.