Photoshop CS5

RGB vs CMYK

RGB default Photoshop setting, but convert to CMYK to print.

Image - Mode - Change to CMYK to print

RGB

CMYK

After changes from RGB to CMYK the filters cant be applied so start off with CMYK in the first place.

A RGB document is only a third of the size of a CMYK file another reason to use CMYK.

How you know your working with non-printable colours?

View - Gamut Warning - Grey parts are where it wont be able to print so there will be a colour shift

Can change using Brightness/contrast and hue in Adjustments.

Above - CMYK

Above - RGB

Above - Gamut Warning - grey area

Above - bright green colour isn't printable for CMYK

Above - Because of the warning on the top right hand side !

Above - Now the ! has gone it means it is printable with CMYK

How we can use spot colour in Photoshop?