CMYK color mode is required for printing your files in full color. If your file was created in RGB color mode, then there will be a color shift when converting from RGB to CMYK. So, if you have designed the files in RGB or Pantone Colors, then they will be converted to CMYK space automatically by our PDF workflow. But to avoid color shift due to this conversion it is advisable that you create your artwork in CMYK modefrom the start.
When making a new document, select CMYK color mode. This will make the colors you have chosen on screen look the same way on paper when printed because printers go through a four-color process which involves the colors (C_yan) (M_agenta) (Y_ellow) (K_ey black).
To Convert Colors to CMYK: Go to File>Document Color mode>CMYK Color
To Convert Colors to CMYK go to Menu > Image> Mode > CMYK color
Another way to make sure the colors are accurate is:
When you open the color picker (CLUT), pick a color. If there is a yellow yield icon that pops up next to the OK button, then the color you picked is not a safe color to choose. The warning icon means that the printer is not capable of printing that exact color. Colors with a warning icon are out of the gamut and will print in a similar color, which is most likely what is wanted. Colors that do not have a yellow yield icon will result in better color accuracy.
Example of Yellow Yield Icon:
For the best color accuracy it is recommended that a hard copy proof is purchased with the order. Even with a hard copy proof colors may only be a 90% match.