User Guide

FontLab 4
198
The BlueScale value is stor ed in Type 1 fonts in a very s trange forma t, but in
the Alignment page you can set it using one of thre e different ways: directly, in
the form that the Type 1 specific ation describes (i.e. it looks like a floa ting
point number), as a PPM size, or as a point s ize on a device with 300 DPI
res olution. Use the BlueScale : combo box to s elect the Bl ueScal e editing
method and edit it in the is equal to: ed it fie ld.
BlueScale Formulas
The “actual” value of the BlueScale value is calculated as:
()
BlueScale
PPM
=
−163333
800 0
.
.
The BlueFuzz value allows you to expand the action range of the
alignment zones in both directions. Thus if you have defined a zone like
(700-715), and BlueFuzz is equal to 2, then the actual zone used will be
(698-717). This is usually used when you are not sure that you correctly set
all the alignment zones or when the characters are not all precisely aligned.
The normal value of this parameter is 0 but by default it is set to 1.
TrueType hinting algorithms do not use BlueScale, BlueFuzz and BlueShift
values.