<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW --- - pdftoppm doesn't render eci_altona-test-suite-v2_technical2_x4.pdf correctly" href="https://bugs.freedesktop.org/show_bug.cgi?id=68986#c18">Comment # 18</a> on <a class="bz_bug_link bz_status_NEW " title="NEW --- - pdftoppm doesn't render eci_altona-test-suite-v2_technical2_x4.pdf correctly" href="https://bugs.freedesktop.org/show_bug.cgi?id=68986">bug 68986</a> from <a class="email" href="mailto:Thomas.Freitag@alfa.de" title="Thomas Freitag <Thomas.Freitag@alfa.de>"> Thomas Freitag</a> <pre>Created <a href="attachment.cgi?id=97905" name="attach_97905" title="wrong output for patch "N"">attachment 97905</a> <a href="attachment.cgi?id=97905&action=edit" title="wrong output for patch "N"">[details]</a> wrong output for patch "N" The complete wrong output for patch "N" if compiled with SPLASH_CMYK and using the overprint parameter for pdftoppm is caused by the fact that in this case DeviceN is used and the blend functions completely erase background with spot colors. BTW, if You run pdftoppm without the overprint parameter, You'll get a better output, BUT: the output is shown in <a href="http://www.eci.org/_media/de/eci_altona-test-suite-v2_technical2_documentation_eng-4.pdf">http://www.eci.org/_media/de/eci_altona-test-suite-v2_technical2_documentation_eng-4.pdf</a> as a sample for incorrect output. The reason for the incorrect output is that the spot color orange is first converted to its RGB components and then the blend function is applied. This is definitely wrong on separable blend modes. The PDF spec says: When performing blending operations in subtractive colour spaces (DeviceCMYK, Separation, and DeviceN), the colour component values shall be complemented (subtracted from 1.0) before the blend function is applied and the results of the function shall then be complemented back before being used.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the assignee for the bug.</li> </ul> </body> </html>