In most packaging work a keyline and a dieline are the same thing: the outline of the flat box, showing where it is cut and folded. When people do separate the two, the dieline is the structural drawing used to make the cutting die, and the keyline is the copy of that outline carried inside the artwork file so the designer can see where the edges and folds fall.
The words get used loosely, often by the same printer in the same email. That rarely matters until someone prints a line that was never meant to print.
Keyline and dieline side by side
| Dieline | Keyline | |
|---|---|---|
| What it is | The structural drawing of the flat package: cuts, creases, perforations and glue areas | The outline of the dieline placed in the artwork file as a guide |
| Who makes it | The manufacturer or a structural designer | Usually the designer, copied from the dieline |
| What it is for | Making the cutting die and checking the structure | Putting artwork, text and images on the right panels |
| Does it print? | No | No |
Where the dieline comes from
A dieline is drawn for the machine and the board. The die maker bends steel rule to follow the cut lines and fits creasing rules along the folds, so everything on the drawing is about structure: which edges are cut, which are folded, where the glue goes. It says nothing about color or graphics.
Where the keyline sits
The keyline lives in the designer’s file, on its own layer above the artwork. It shows the panel edges and fold lines so the front of the design lands on the front panel and the barcode stays off a fold. Some designers add position marks to it, such as a box showing where a window or a barcode has to go. On a busy file it is the thing everyone looks at and nobody should print.
The other meaning of keyline
Outside packaging, and especially in commercial print, a keyline can also mean a thin printed rule around a photo or a block of text. That keyline does print. If a printer asks whether you want a keyline around an image, this is what they mean, and it has nothing to do with the box structure.
What color is a keyline?
There is no universal keyline color. The usual practice is one spot color with an unmistakable name, such as Dieline or Keyline, in a bright color that cannot be mistaken for artwork, set to overprint on a non-printing layer. Printers differ, so if yours asks for a particular name or color, use theirs. On our templates the cut line is solid magenta, and the full legend is in our guide to dieline line types.
Why neither one should print
The most common dieline mistake on a first order is a keyline left on a printing layer. It shows up as a thin colored outline around the finished box. Keep it on its own layer, name it clearly, and say so when you send the file. We look for it on the free digital proof before anything prints, but it is quicker to set it up right the first time.
Send the inside dimensions and the box style, and a specialist replies within one business day. Free design help and no minimum order.
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