From: zisk@adobe.com (Stephen Zisk)
Newsgroups: comp.lang.postscript
Subject: Re: Postscript Font Scaling & Reduction
Date: 19 Nov 92 16:15:19 GMT
Followup-To: comp.lang.postscript
Distribution: na
Organization: Adobe Systems Incorporated

In response to what Chris Lewis and Walter C3arlip wrote, and amplifying
what Jim Delahunt said, I want to add my $.02. As a caveat, let me say
I am not a type designer or expert, just an interested amateur.

    1.) The "design center" for scaling Type 1 fonts (except, of course,
        for *some* Multiple Master typefaces), is linear scaling at all
        point sizes.

    2.) Hints are used to overcome the limitations of low-resolution
        digital printers. They primarily prevent various kinds of uneven
        "color" and illegible characters. They do not have substantial
        effect at large point sizes and high resolutions.

    3.) The modification of a type design for use at different sizes,
        often called optical scaling, is one available axis of design
        in Multiple Master typefaces. This idea has been around a very
        long time, and is generally applied only to serif designs.
    4.) The reasons for different designs at different sizes in hot type
        (and Multiple Master Fonts) are complex and subtle:
        a.) With some printing techniques, especially older ones, ink
            does not stay where you want it, and type designs must be
            modified at smaller sizes to remain readable. This may mean
            simplification; it may also mean addition of strange
            features like inkwells to control ink placement.
        b.) For "readabilty" purposes in large blocks of text, it may
            be useful to sacrifice some of the uniqueness of a design.
            This may mean thickening serifs, lessening contrast between
            thin and thick strokes, increasing x-height, even changing
            the angles of bowls, all in the interest of smooth reading.
        c.) With physical pieces of metal, strength and integrity of
            the type through a long print run might dictate design
            changes, both at small and large sizes. This was especially
            true before the industrial revolution, as tooling hard
            metals was very difficult, and softer ones were used.

    5.) Some type designs have been intentionally tailored to the
        strengths and weaknesses of low-resolution printers. These
        designs might, indeed, appear "blocky" or "coarse" at higher
        resolutions or point sizes. Even "normal" fonts may not look as
        good at large sizes as faces specifically designed it. This is
        why, even before Multiple Masters, some fonts came with "Titling
        Caps". This is also why lighter weights are sometimes chosen for
        larger sizes (advertising use notwithstanding).

    6.) There is no reason "linear scaling" should look bad within a
        common-sense range of sizes. Hints will regularize things at
        small sizes, and the larger number of available pixels will make
        things look good at large sizes. The reasons for choosing a
        Multiple Master face should center on design flexibility,
        including better control of appearance at small sizes (for
        readability) and large sizes (for "elegance", faithfulness to
        the design, or whatever you want to label it.

Stephen Zisk (zisk@adobe.com)  Disclaimer: These are my personal views
Adobe Systems Incorporated     and do not represent the position of
Eastern Regional Office        Adobe Systems Incorporated.
24 New England Exec. Park
Burlington, MA 01803           They pay me but they don't muzzle me!