This might be an error but i've got a feeling its something to do with preparing artwork for printing.
I've received some packaging artwork from my client that i need to edit, it's made by a different graphic designer. It has two main layers, one called "artwork" which has the basic artwork on it, here is a selected area of it:
I have not seen this before but i assume this is somehow related to making the colours print right? perhaps the red areas are meant to be printed white, perhaps to enhance the colours that will be printed over it? Am i in the ballpark here?
If that's the case then what is this technique called? When is it necessary to do?
Any help appreciated, seriously scratching my head over here.