Hi all, the idea of spot colours is qite simple. Imagine that you want to print a monochrome document, but not black, let say red on white. The red colour will have to be mixed from yellow and magenta possibly with a small amount of black and/or cyan. In such a case you will have to prepare four separations. The software does it easily but you will have to pay them and pay all CMYK colours. If you use red as a spot colour, you need just one separation and one colour. The document can be printed as if it were black&white but they will use a red colour instead of the black one. I do it quite often without using the machinery of spot colours, I just instruct them to use the spot colour and put the instruction to the crop marks. It is even possible to use two spot colours because such offset printers exist that can print in two colours. Thus I use black + red. My PDF is prepared to contain only black and magenta separations (yellow and cyan are empty) and I put an instraction that the magenta separation should be printed with a specified red. I do not fully understand the machinery of spot colours in PDF. I hope that it allows to see visually the right colour on screen while providing the correct separations. Each Pantone colour has its approximate CMYK values so you can have realistic preview. In my simplistic method I see false colours.
Usage of spot colours has these advantages: 1. It is cheaper because less separations are needed (unless you have too many spot colours) 2. You have the possibility to use more saturated colour than can be created by CMYK (colours that are out of CMYK gamut) 3. You put less ink on the paper which is technologically better (prevents distorsion of the paper during drying the inks, the drying is faster) Spot colours are allowed in PDF/X. Zdeněk Wagner http://ttsm.icpf.cas.cz/team/wagner.shtml http://icebearsoft.euweb.cz 2016-06-27 15:46 GMT+02:00 Philip Taylor <p.tay...@rhul.ac.uk>: > Thank you for the suggestion, Apostolos, but in fact I'm not trying to use > colour (/qua/ colour) at all. Rather, I am trying to ensure that all pages > that do not /require/ colour use only "true" black, CMYK black or greyscale > -- not RGB black, for example. > > ** Phil. > -------- > Apostolos Syropoulos wrote: > > If you want to use spot colors, then you > could try to use the xespoycolor > package. I had no idea what spot colors > are when a publisher asked me to > use spot colors for colored frames. > So I ported the spotcolor package > to solve the problem of colored frames > > > > > > -------------------------------------------------- > Subscriptions, Archive, and List information, etc.: > http://tug.org/mailman/listinfo/xetex > -------------------------------------------------- Subscriptions, Archive, and List information, etc.: http://tug.org/mailman/listinfo/xetex