by URW, a German company, in the 80's for converting existing
logos into digital format for use on
computer driven printing, plotting and sign cutting devices.
Ikarus uses a cubic spline mathematical model of the outline
shape of each character within a typeface to give a fully
scalable representation. This means that any rendering resolution
can be attained (by rasterisation) with equal accuracy from one
relatively small set of data. The Ikarus coordinates for a shape
all fall on the outline of that shape (as opposed to Bezier curves where there are
'guide' points which can be inside or outside the outline).
Originally invented by Peter Karrow, Ikarus (German spelling of
the mythical figure Icarus) got its name from the frequency with which it
crashed in the early days of its development. It was designed to
run on Mini computers such as
DEC Vax and later adapted to Micro computers as they became
By the nineteen eighties there was a huge library of typefaces
and logos which existed as photographic film and which needed to be
input into computers for the latest generation of printing and
sign-making devices. Unfortunately, normal scanning gives a rasterized shape at the resolution of the scanning
device which leads to degradation of quality when scaling up and
down. This is a particular concern in the sign making industry where individual letters may
be metres across, many times the size of the original artwork.
Ikarus enables a human operator to input the features of a complex
shape with curves, corners and straight lines (e.g. a letter of the
alphabet) to a computer which stores it as a mathematical function
which is for all intents and purposes independent of the size of
the original artwork and of the final output.
The advent of desktop publishing in the eighties using
Macintosh computers coupled with laser printers led to a shift away from a
small number of specialized print bureaux acquiring relatively
expensive fonts to a growing market for cheap mass produced fonts.
The drawback of Ikarus for catering for this new market was that,
while extremely accurate, it was very labour intensive.
The first stage of digitization of a typeface is prepare the
artwork by marking up. This involves putting tick marks around any
curves at approximately 30 degree intervals along with extra
tangent points where a curve blends onto a straight line. Some form
of accurate graphics tablet is then used to input three
types of points: curve points, corner points and tangent points.
Any irregularities (e.g. lumps and flat spots) are then edited out
by adjusting the position of the points on the computer. The human
eye is extremely sensitive to spotting irregularities on smooth
outlines and typical adjustments are of the order of tenths of
millimetres on a character one hundred millimetres high. As the
computer screen displays a rasterized image at relatively low
resolution, high quality print outs (traditionally bromides) or cuts in film
(Ulano) are used to proof the digitized shapes.
This information is based on the article Ikarus_%28software%29 from the free encyclopedia Wikipedia and is licensed under the GNU Free Documentation License. On Wikipedia is a list of authors available.