Letterpress text

The whole illusion is one pixel of shadow and an assumption about where the light is. We read light as coming from above, so a groove cut into a surface is shaded along its top edge and catches a highlight along its bottom edge. Copy that: set the type a little darker than the surface it sits on, then put a white or near white shadow one pixel below it, and the letters read as pressed in. Invert the pair, a light fill with a dark shadow below, and the same type reads as raised instead. Both need a mid tone surface to work on, since a highlight is invisible on white and a shadow is invisible on black, and both need the fill to sit close in value to the background, because the moment the letters have real contrast the eye stops reading a depression and starts reading coloured text with an outline.

The name comes from a real press, where inked metal type is driven into damp paper and leaves an impression you can feel with a thumb. That bite was originally considered a fault: a nineteenth century pressman aimed to kiss the paper, and visible indentation meant the press was set too heavy. Fine printers reversed the judgement in the twentieth century, deep impression became the signature of hand printed work, and the sensation of type having physically happened to the paper is now most of what people pay a letterpress shop for.

On the web the effect had a very sharp career. It was everywhere from about 2009 to 2012, on every heading of every grey gradient interface of the period, cheap to apply and convincing at display sizes. Then flat design arrived and executed the entire category of surface simulation in about eighteen months, and the effect went from house style to period marker without an intermediate stage. It kept one legitimate descendant: the single pixel light line along the top edge of a dark control, which is the same shadow doing structural work rather than decorative work.

It survives honestly in three places. In print and on physical goods, where the impression is real. In large display type set on a genuinely mid tone surface, where the low contrast is a deliberate part of the composition. And in the small structural highlight described above. Everywhere else it fails the same two tests. The contrast it depends on is too low for body copy to be readable, so it cannot be used on anything anyone has to read at length, and it is invisible below about eighteen pixels, where a one pixel offset is simply blur. Remember that a theme switch inverts the physics: a shadow that reads as a groove on a pale surface reads as nothing at all on a dark one unless both the fill and the offset are swapped with it.