Checking Line Weights for Letterpress

Letterpress printing, unlike digital or flat printing methods, requires a relief plate of the artwork to be made for printing. Modern plates are generally made by exposing designs onto photopolymer and washing out the unexposed areas. This creates a hard raised surface to which ink is applied during printing. You can basically think of this as a very hard, large stamp.

The nature of this process and the great pressure applied to the plate during printing means that thin, fine details will not necessarily print well. Lines and dots that are too fine have the potential of either not exposing and washing away on the plate, or they may compress or break during printing.

Checking artwork

While we use a relatively thin plate that holds finer details, it is still important to check your artwork to make sure it meets the minimum recommendations. Lines should be at least 0.25 points thick (finer hairlines will not work). Dots should be at least 1 point in size. This includes fine details in illustrations and the small lines and dots that make up the letterforms.

Through preparing hundreds of plates we’ve adopted some simple ways of checking line weights and thickness. These can help take the guess work out of whether or not your artwork is suitable for letterpress. We’ll use the invitation design below as an example.

creating reference lines

Just by looking at this invitation design it can be difficult to tell if the line weights are sufficient or if they are too fine. We’ve found the best way to double check is to create a set of lines and dots that you can paste into a document and dragged around for comparison.

Reference lines and dot created in Adobe Illustrator

Basically we’ve created a simple crosshair from two intersecting lines that are each 0.25 points thick and a small dot that is 1 point. If you’re using Adobe CC it’s a great idea to save this to your libraries so you can quickly add it to any document you’re working on for reference.

You can download our reference set here to save you the trouble of creating your own!

Comparing and thickening Lines

By pasting the reference lines into your design document (in this case in Illustrator) you can drag them around and compare their line weight to those of your design. Zooming in really close will help make this easier.

Below is a detail of some of the small text in the invite beside the reference lines for comparison. In the first screenshot you can see that the thin stokes and serifs of the text are finer than the recommended 0.25 points.

Don’t panic, it’s not time to find another font or make the whole design bigger. The easiest fix is to add a very thin outlining stroke to the letters. Start very small and keep making the stroke a little bigger until the letters look as thick as the reference 0.25 point line.

Fine details in letters are too fine

0.06pt stroke added to the letters thickens the fine lines

In this case a 0.06 point stroke was just enough to thicken the letters for letterpress. When done correctly the difference is very subtle but the improvement it makes to the finished print is huge.

Illustrator stroke settings

Detail of the very slight stoke applied to the fine text

Now it’s time to continue checking all other areas of the design and thickening up and lines as necessary. Just keep dragging around the reference lines, zooming in and applying a stroke where needed. Not all type will need a stroke and not every piece will need the same thickness stroke.

Fine lines in letters are just a little too thin

A 0.04pt stroke is enough to thicken these letters

In this particular invite the large text for the names was thick enough and the small italic text only needed a 0.04 pt stroke. We’ll keep applying the same 0.06 and 0.04 point stroke to all the small text until all the lines in the design met the minimums for printing. The changes are subtle and hardly noticeable but will make a big difference!

Below is the final version of the invite ready for print.

The finished invite with slightly thickened lines. The changes are hardly noticeable but will make a big difference to the final printed piece.