On Thursday 03 September 2009 07:55:02 am Peter Nermander wrote: > > now, and in the last few issues experienced problems. Eventually > > it turned out that it was all caused by me exporting PDFs for > > "Printer", not "Greyscale". PDFs exported for "Printer" are > > actually RGB, not greyscale - even though the entire document > > doesn't contain a single element in color. So a description of > > what these two options do would be welcome :-) > > It has been mentioned several times on this list. > > Printer means PDF is exported as CMYK (the "printer" here means the > profession, not the device)
I always thought that this means that the output will be converted to the "Printer:" color space that is set in the Color Management Preferences dialog. That color space could be a CMYK, RGB, Gray or device N color space depending on the profile that is set in the Color Management preferences. And no it does mean the "printer" (as in a device) and not the profession since the profile set in the CM preferences dialog is for a specific device. > > Screen/web means RGB I think Screen/Web means that the document will be converted to sRGB. Saying that a document is converted to RGB is colorimetricly meaningless. > (and is to be used for most desktop and office > printers, because they are made to accept RGB data and trying to print > a CMYK PDF to those devices mean that the CMYK will first be converted > to RGB by the computer and then to CMYK again by the printer driver) This is true on Windows and OS/X using vendor supplied drivers IF you don't have a good profile for the printer/paper/ink/driver and work flow. Many of the drivers used on *nix machines can also accept at a native level CMYK, Gray and even in some cases device N input. For example the GutenPrint drivers support RGB, CMYK, Gray and device N input at a native level on many printers including the Epson R2400 I have. > > Grayscale means (if I understand right) CMYK without CMY (intended for > when you print with only black ink). I am not sure about this but I would expect a "Gray" color space document to only have one subtractive channel. Hal
