is it possible to use CMYK overprinting without using the CMYKColorSep class, which always generates a new seperate color in the printer settings, i just want to use overprinting with the standard 4 CMYK inks (colour-separated PDF output, as stated in the 2.4 changelog)
here my example code (reportlab 2.4 needed):
from reportlab.graphics.shapes import Rect
from reportlab.lib.colors import PCMYKColor, PCMYKColorSep
from reportlab.pdfgen.canvas import Canvas
black = PCMYKColor(0, 0, 0, 100)
blue = PCMYKColor(91.0, 43.0, 0.0, 0.0)
red = PCMYKColorSep( 0.0, 100.0, 91.0, 0.0, spotName='PANTONE 485 CV',density=100)
red2 = PCMYKColor( 0.0, 100.0, 91.0, 0.0, knockout=0) #knockout does nothing?
c = Canvas('test.pdf', (420,200))
c.setFillColor(black)
c.setFont('Helvetica', 10)
c.drawString(25,180, 'overprint w. CMYKColorSep')
c.setFillOverprint(True)
c.setFillColor(blue)
c.rect(25,25,100,100, fill=True, stroke=False)
c.setFillColor(red)
c.rect(100,75,100,100, fill=True, stroke=False)
c.setFillColor(black)
c.drawString(225,180, 'overprint w. plain CMYKColor (does not work)')
c.setFillColor(blue)
c.rect(225,25,100,100, fill=True, stroke=False)
c.setFillColor(red2)
c.rect(300,75,100,100, fill=True, stroke=False)
c.save()
note: you need to enable the overprinting preview in acrobat reader pro to correctly view this.
if this does not work with reportlab, do you know any other server-side alternative to generate pdf, where overprinting does work?
thank you very much
this feature is not implemented in Reportlab 2.4. But they will do it with their next major release.