Uncontrollable shifts occur during the printing process as the paper travels through the machine and this is a restriction of all printing methods.
For example, if you approve an online PDF proof with an image centred on the page, there is a chance for the paper to shift in any direction causing the image to look off-centre in the end product. The standard tolerance that is deemed acceptable is 1/16", although some specific stocks will have larger shift tolerances up to 1/8".
Digital Output vs Offset
Digital machines use rollers to move and align paper during the printing process, and it naturally has a higher tolerance for shifts than that of offset printing.
The degree of shifts depend on the thickness and make of the stock - the thicker the paper, the higher risk of shifting.
Our exclusive line of stocks such as wood, pulp, and thicker stocks (20pt+) are more prone to shifting as they are more rigid compared to standard papers.
Although shifts are minimal, they are more visible with designs that have borders as they may be uneven all around after trimming or to designs that have artwork bleeding over the edge.
Custom products that require additional steps or special processes after printing (such as applying spot UV, foiling, or embossing) may appear mis-registered (misaligned) due to shifting.
For example, if "Jukebox" from "Jukebox Print" needed to be foiled, we would print the word "Print" first, and then foil "Jukebox" after. The two words may not perfectly register because the paper may shift during printing and foiling, which causes the position of the words to vary on the paper.
Registering printed artwork to a score line may also cause the artwork to appear mis-registered, (the artwork may shift slightly onto the next panel). This is due to unavoidable shifts between the trimming and folding processes. We recommend a safety margin of at least 0.125 inches from the folded edge.