Theatre Design & Technology - Spring 1989 - 34

the units of measurement are derived (e.g., the standard
footcandle). And still other standards specify constmction
and/or performance for the purpose of assuring quali ty
le.g., purchasing specifications) or safety le.g., the National
Electrical Code).
For our purposes, let's start with a working definition of
a standard as" a consensus among multiple manufacturers
as to the values necessaq to assure the interchangability
and/or interconnectability of their products."
The purpose of such a standard is first and foremost "to
assure interchangability and/or interconnectability"
Drafting a standard should not be an end in itself. Yet some
people approach standards as abstractions, and while standards (like tax law) can be attractive mental exercises with
their own abstract logic, stmcture, and internal ethics, a
lighting industry standard must achieve its practical purpose to be of any use. This is not to say that logic, stmcture, and ethics are bad (to the contrary; a well-drafted
standard reflects them all), but they should not drive the
drafting of a standard to the unnecessary detriment of its
practical purpose.
Clearly; the application determines just what values are
necessary. Those necessary to specify interchangeable
gobo holders will be very different from those needed for a
digital communications protocol. But deciding what
values must be defined, what the actual values and tolerances should be, and how all three are best expressed
should be determined for both applications by the same
functional test: Without these values, could r interchange
these gobo holders? Could r interconnect these products?
STANDARDS MUST REFLECT A
CONSENSUS

A key word in the definition is "consensus." Standards are
the product of a social process, and not necessarily a
strictly technical or scientific one. A consensus is, after
all, an agreement. Arriving at that agreement can take
many routes.
For one, you can have a de facto standard without a
formal written "standard." That is, multiple manufacturers can independently decide to do things the same way
(or at least similarly enough) to achieve interchangabili ty
or interconnectability. For example, there hasn't been a
formal standard specifying how to build a pin connector.
And manufacturers didn't formally agree to build consoles
and dimmers around a 0- lO volt range.
A manufacturer who creates a new product or dominates the sales of one may; intentionally or not, set a
"standard" simply because it and subsequent producers
stay with decisions made when that product was first
introduced. Such decisions can come from some strange
places. The first gels were literally sheets shaved off blocks
of dyed gelatin poured into tin pans. When you wonder
why today's sheet of gel is such a poor fit for multiples of
"standard" gel frame sizes, do you also wonder if the sheet
size is simply that of the tin pans readily available a centuryago?
Another reason can be technical. Because entertainment lighting is generally restricted to components, materials, and techniques in current commercial use,
manufacturers frequently have to choose from the same
catalogs and may end up making the same or similar
choices. Many of the voltage ranges used by consoles with
discrete analog Outputs were determined by the voltage
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SPRING 1989

limits of common transformers and power supplies. The
subsequent trend away from dimnler signals extending
above lO volts was also caused more by the inherent limitations on the maximum operating voltage of the CMOStype rcs that the manufacturers began using than by any
formal agreement between them.
Attempting to build cost-competitive products that accomplish the same function and meet the same purchasing specifications lanother form of standard) can also
influence similar designs by different manufacturers.
A major problem with these unwritten standards is that
the "agreement" is largely undocumented. The only references are the examples of product in the field and - just as
importantly - no agreemeur exists on which and what
values must be maintained to assure continued interchangability. 0 tolerances are established, for example.
You could measure a pin connector or the output of a
lighting board and determine how to engineer something
that will interconnect with the one that you measured. But
will it work with all the ones you didn't measure, particularly if several manufacturers each produce variations on
that product?
Build lOOO copies of the same product or component and
none of them will be identical. That is, variations in the
materials and in the machinery and labor used to fabricate
each unit will produce subtle differences among them.
"Quality control" is the setting of internal standards by a
manufacturer for a product. Because no two copies can be
tmly identical, part of the quality control process is defining not only the values of a perfect unit, but the acceptable
degree of variation from those values.
Specifying lor at least providing for) such tolerances is
therefore an essential part of any standards process. Many
manufacturers in general industry regard (and protect) the
tolerances for their products as valuable trade secrets, because tolerances (as much as the ideal values) define the
difference between a functional and a non-functional
product.
Values and tolerances reflect valuable know-how, and
are therefore a potential comnlercial advantage not to be
given away lightly. This is where the non-technical aspects
of standards come fon,yard.
Manufacturers in various industries have used incompatibility as a sales tool. While product differences could
be explained by engineering choices, more than one potential purchaser, when told that a manufacturer would not
guarantee that one of its products could be used with
anyone else's to assemble a working system, has come
away with the impression that the manufacturer is using
incompatibility to sell more systems - and to make the
customer more dependent on that manufacturer for future
upgrades.
A standard, formal or not, that succeeds at "assuring
interchangability and/or interconnectability" also assures the customer that he or she has a choice of sources
for a given product or component of a system. That can
mean more competitive pricing and the ability to assemble a system from the best or the most appropriate
components.
When a given manufacturer feels it can produce and sell
a courplete system suitable for its market, there is little
reason for it to make the effort to conform to someone
else's standard. Nor does the manufacturer feel obliged to
provide its competitors with its own internal standards so
that those competitors can produce compatible products
or components.

Table of Contents for the Digital Edition of Theatre Design & Technology - Spring 1989