Theatre Design & Technology - Fall 1993 - 27

COMPUTER SCANNED IMAGES
IN THEATRICAL DESIGN
PATRICK GILL & KIM HARTSHORN
relarively inexpensive addirion (0 a compurerized
designer's graphics (Ools,
rhe oprical scanner, increases anisric oprions bv
enabling rhe quick and
easy rransFer of inFormarion From prinred or phorographic media
inro digiral Formar. These scanned images,
when improved wim graphic soFrware packages and rransFerred ro a marerial srage
using srandard prinrers or plorrers, provide
a new approach ro rradirional areas of
design and sragecraFr.
To undersrand how
ro eFFecrively scan
images, a basic knowledge of digiral graphics is
imponanr. The srandard
black and whire Macinrosh screen consisrs of
many riny dors or pixels,
each of which con rains
one inFormarion unir
called a bir. There are
512 pixels horizonrally,
342 lines of pixels verrically, and 72 pixels per
square inch in rhe srandard nine-inch Macinrosh screen. The compurer sees each bir as
eirher on or off. This on
or oFF srarus, assigned ro each bir by rhe
soFrware, corresponds ro black or whire dors
on rhe screen.
Each pixel on a gray scale screen conrains eighr birs rhar correspond ro six shades
of gray berween black and whire. Pixels on a
color screen can conrain From eighr ro 32
birs rhar combine ro creare colors. So, an

eighr-bir grav-scale screen can displav r 6
shade of gray and a 24-bir color screen can
displa\' 16 million diFFerenr colors (Figure

1)1
OpricaJ scanners converr images inro a
series of rhese dors rhar are srored in rhe
compurer's memory as files called birmaps.
They resemble rhe grains of lighr-sensirive
chemicals on phorographic film. To carry
rhe analogy a bir Furrher, rhe more numerous and finer rhe chemical grains on rhe
film, rhe higher rhe resolurion of rhe inirial
recorded image. 0, rhe more dors in a
birmap, rhe higher rhe resolurion of rhe dig-

iral image.
\X/irh film, rhe proper use of various filrers, careFul Focus of rhe enlarger, and
mericulous riming of rhe chemical processes
also comribure significanrly ro rhe phorograph. So, anorher rype of file Formar, a
drawn or vecrored objecr and rhe diFFerenr
modificarion merhods ir allows, can help ro

provide a berrer digiral image. Bir-mapped
images have jagged edges ar lower primer
resolurions and improve onk if rhe number
of dors in rhe birmap is equal ro or higher
rhan rhe prinrer resolurion. Drawn objecr
images appear sharp ar lower resolurions
and improve as rhe resolurion of rhe prinrer
increases, because rhey srore as a series of
marhemarical Funcrions rhar rell individual
birs ro rurn on or off regardless of rhe resolurion.
The reason ro consider rhe use of borh
rypes of images is rhar bir-mapped
images-such as scanned documenrs, when
convened From birmaps
ro drawn objecrs by rracing-or drawn objecrswhen convened ro
birmaps-can beneFir
From rhe unique properries rhar each Formar
offers (Figure 2).
When prinring borh
rypes, drawn objecrs have
rhree basic advanrages
over birmaps. Because
drawn objecrs srore as
Funcrions, rhey require
much less memory. This
;lllows rhe soFrware ro run
much Fasrer and perm irs
5 much more enhanced resolurions. Since rhese
images are independenr of rhe resolurion of
rhe moniror screen. rhe soFrware prinrs
rhem ro rhe maximum resolurion of rhe
pnnrer.
An advanrage of bir-mapped images is
rhar rhey are easier ro modifY rhan objecr
image. This is because alrerarions ro
birmap occur ar rhe primary level of rhe
TD&T

1993 FAll

25
Table of Contents for the Digital Edition of Theatre Design & Technology - Fall 1993
