Color spaces

A PDF document can contain objects of different color spaces: Separation, DeviceN, CMYK, Gray, calibrated Gray or RGB, Lab or ICC-based colors. The color space of the object has an impact on the object’s overprint behavior. The following rules apply here:

Color space

Object type

Overprint mode

Rule

Separation

DeviceN

Irrelevant

Irrelevant

Only those inks are specified as listed in the respective color space.

Separation Black, for example, will only have the black ink speci­fied, not cyan, magenta or yellow.

Gray

RGB

Lab

ICC-based colors

Calibrated Gray or RGB

Irrelevant

Irrelevant

Cyan, magenta, yellow and black inks are specified. To determine the percentage of the inks in non-CMYK objects, the colors in these objects are converted to CMYK according to the normal color conver­sion rules.

An object in Gray, for example, may have the following inks speci­fied:

C: 0 %

M: 0 %

Y: 0 %

K: 60 %

Consequently, objects in Gray will always knock out the underlying cyan, magenta or yellow, regardless of the object type or overprint mode.

CMYK

Image

Shading

Irrelevant

Text

Line art

Image masks

Standard (OPM 0)

Illustrator (OPM 1)

Only those inks are specified of which the tint value is not equal to zero.

We learn the following from this overview:


Ink

Object in spot color black, Gray or 100 % K

Object in Separation Black

Cyan

0 %

 

Magenta

0 %

 

Yellow

0 %

 

Black

100 %

100 %