A California Job Case is a kind of type case

Type case

A type case is a compartmentalized wooden box used to store movable type used in letterpress printing....

: a compartmentalized wooden box used to store movable type

Movable type

Movable type is the system of printing and typography that uses movable components to reproduce the elements of a document ....

 used in letterpress printing

Letterpress printing

Letterpress printing is relief printing of text and image using a press with a "type-high bed" printing press and movable type, in which a reversed, raised surface is inked and then pressed into a sheet of paper to obtain a positive right-reading image...

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Traditionally, upper and lower case type were each kept in a separate case (or tray). As printers became more mobile, a combined case became preferred as it was easier to transport. The combined case became very popular during the western expansion of the United States in the 19th century.

The defining characteristic of the California Job case is the layout, documented by Ringwalt as used by San Francisco printers. This modification of the Italic layout was claimed to reduce the compositor's hand travel by more than half a mile per day.
This typecase consists of 89 compartments, most of which are assigned to specific slugs. Variations add additional symbols to unassigned compartments.

Numerals and symbols are at the top, lower case, punctuation and variable width spaces on the left, and capitals are on the right. Lower case compartment position and size varies according to the frequency of occurrence of the letter contained. Uppercase compartments are uniform size, ordered A to Z. (J & U were not used by early English printers, so they are assigned compartments following Z.)

This organization keeps larger quantities of more the frequently used slugs in convenient reach of the typesetter. Ligatures and several widths of space improve efficiency.

A typecase (don't say drawer) with every character and space in its proper place is called 'clean', while a ‘dirty’ case has characters mixed up, generally by careless distribution as they were returned. A spilled case is called 'pied'.

Each size and style of font is kept in its own tray, and trays are kept in a cabinet with slots making each tray appear as a removable drawer. The cabinet may offer the type setter a work surface at a convenient height, often a composer's work stand.