Monday, 26 March 2012

Theory Into Practise Letterpress Research.

General Info
The letterpress printing process is one of the oldest ways of getting the printed word on to a page. It relies on a physical representation of each letter being inked and then pressed against the paper — and this is why it’s both interesting and expensive. Thinking a little further about it for each page the printer needs a piece of metal to represent every single character; a way of applying ink to each character and a machine to force the metal and paper together. It follows that changing from bold to italic, for example, will need a totally new set of metal characters rather than a few clicks of a mouse. Other printing processes like lithography or digital printing are more flexible, quick and less expensive. But while commercial letterpress is in decline there are many who are starting from scratch with this wonderful process.
It’s a constraining process but allows a certain freedom which inspires lots of designers. The time taken can induce a concentration which excludes the immediate world. In many ways letterpress is the antithesis of the modern graphics work. It provides a wonderful and absorbing pastime that demands just as much time, space and money as you would like to allow.

Leading and other spacing materials
Leading is a term that has made it’s way to the graphic designer’s computer.  It defines the gap between lines and in letterpress printing it is done by inserting a thin strip of lead.Leads are around the same height as spacing and so don’t print.  They vary in length and also width.  On width, leads are supplied in point sizes and are most commonly available in 1, 1½, 2 and 3 points.
Clumps can be thought of as extra wide spaces: they are usually made in multiples of an em and so 12pt clumps will normally be 12, 24, 36 or 48pt wide.  They are made of the same material as spaces and are the same height.  A secondary use here is in word spacing for larger type sizes: a 12 x 36 pt clump makes a useful space for 36pt type.
Reglet is line spacing that is larger than leads.  Almost always made of wood and the same height as leads, it is used to give more space between lines and is most often employed on title pages or notices to create white space between lines.
Next in terms of size are quotations, originally designed to correctly space side-notes and quotations in book work.  They are metal and full spaces that are multiples of clumps.  Typically 48pt and larger they are an accurate way of filling space.
Furniture is the largest of the spacing material.  Originally wood, it is supplied in ems rather than points.  Finding wood to suffer from warping and easily damaged, printers began to use metal furniture (from the same material as spaces), and then aluminium girder pattern furniture which was lighter.  One development was the use of a Formica-dervied material called Resalite.  Stephenson, Blake claimed this was better than metal furniture because damage on one dimension would not cause problems with accuracy.
This rather grand sounding material is used to set curved lines of type.  It’s not used too often now, but the was a fad for firm names to be set in an arc or circle.  These are always supplied in pairs and have two surfaces that match each other.  Type is set between them and then locked up.  There are a number of methods used to get this to work corrrectly: setting type against sticky tape to hold them in place; or spacing them with wet paper to form a sold mass once dry.
Squeeze’ is the term to describe the difference between the length of a line of type as sat in the composing stick; and the same line when locked up in a chase ready to print.  The accepted view was that a compositor should set type a little longer than the measure (line length) but the forces of quoins would squeeze the type together and bring it back to the intended size.
Lock Up
Knowing that all the matter to be printed has to be locked together in a metal frame (the chase) leads to some important questions, the primary one being: how can I make sure that everything will be level and maintain its structure?  This practice is calledLockup.  Where lockup is weak, it allows things to move within the forme and causes inaccuracies.  In addition, loose material (like spaces) can work up from the forme to touch the printed page.  This leaves a black square mark between words where the spacing material has been inked and printed.
In longer-run jobs the impact of rising spaces is magnified: if a space is loose and can work up on each impression, a movement of just 0.001″ per impression will cause the space to print on the page after just 500 impressions.  In the world of commercial, high-volume letterpress this could be a massive problem.

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