Given a duotone object with 70% Red and 30% black that is rendered with overprint on top of a background in ICC-tagged CMYK.
The duotone object uses the inks Red and black. The background must be identified as inks, so the ICC-tagged CMYK background is converted to regular CMYK. This conversion is performed according to ICC profiles that may be specified in the preferences. Suppose the background is converted to 20% cyan, 21% magenta, 22% yellow and 23% black. The overprint mode does not influence this.
| Background object | Foreground object | |
|---|---|---|
 |
 |
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Object type |
not specified |
not specified |
|
Overprint mode |
OPM 0 or OPM 1 (no difference) |
|
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Color space |
ICC-tagged CMYK, converted to: C: 20 % M: 21 % Y: 22 % K: 23 % |
Duotone: Red: 70 % Black: 30 % |
The only common color is Black. There is no difference in overprint behavior between a spot color that is named “Black” and “Black” ink that is used to render the K plate of CMYK. The other colors are used either by the foreground object or by the background object.
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C: 20 % M: 21 % Y: 22 % K: 30 % Spot color Red 70 % |