What is 6 color printing, is it multicolor process printing? What setting do I have to keep in Photoshop, Do I have to create an extra channel in the channel palette?
The digital Hexachrome printing process uses CMYK inks plus Orange and Green inks. With Hexachrome you have a wider color gamut and it may produce better, more vibrant images than 4C alone.
Before preparing a print project for 6C or 8C process printing, talk to your printing service. Not all printers offer 6C/8C process printing or may only offer specific types of digital and/or offset color printing, such as only digital Hexachrome. Additionally, your printer can tell you how best to handle color separations and other prepress tasks when preparing files for 6C or 8C process color printing.