Designing for print can be quite the task for beginners and even seasoned designers at times.
One of the problems we seem to run into quite a bit is helping customers use the right black for printing.
A lot of designs that come through here are designed in Photoshop. it seems to be the goto with un-seasoned designers.
Usually when this becomes an issue is when designers mix programs for their design. Such as using Photoshop for their background and finishing up the design in InDesign for the foreground.
Black is black right? Nope.