Prototype plates, often called test plates, are manufactured to try out a new idea.  This may be a completely new plate design, manufacturing technique, or a proposed change to an existing design.  A lot goes into manufacturing license plates, and nothing helps the thought process along more than having some prototypes on file to compare various designs and techniques.  Prototype plates usually resemble the final product, but important differences can include:

Color Trials

In order to decide what colors to ultimately use, different color combinations are often tried out. This means taking the proposed design and painting it with various color combinations.  This helps determine what color combinations are easy to read, and which are not.  These plates are kept on file for future reference in cases where colors are changed frequently such as the Quebec plates of the 60s and 70s.
 

	Color trial for 1973 PEI.  The color on the right was the one chosen for the passenger plates of that year.
	Ontario trial for 1946.  Instead of settling on the striking yellow of 1940, the people who decide these things chose the boring white on black.  These became the colors of choice for years to come.  Incidentally the non-passenger plates of 1952 did use the yellow.

Design trials

If manufacturers are to bid on a contract to provide license plates for the Province, they usually have to submit a few examples of the plates they propose to make.  It is likely the 1921 Alberta plate shown here is a manufacturer's sample, the same manufacturer that made the 1920 Ontario plates because the metal base and font for the numbers are identical.  Compare them below.  In the end a different manufacturer was chosen as the 1921 Alberta plates are embossed, with "ALTA" and "1921" on the right.

Note the similarities in manufacture (bolt holes, number dies).
 

Several candidate designs were no doubt considered for a radically designed plate such as the Quebec Expo67 / Confederation pair.  These are all considered prototypes:

The first two zeros on the blue prototype are reflectorized - that's why they look brighter.
Looks like they forgot to put the province name on that second design!
 

With all the new graphic plates that are appearing on the roads nowadays, no doubt various designs were considered before making a choice.  For every new plate, you can usually assume it was only one of many possible designs considered.

Reflectorization - an early experiment

A reflectorized plate, makes it easier to read at night against a bright light.  Not to mention making the car itself easier to spot at night with something reflective on the back bumper.  The modern type of reflectorization in common use today is a strip of Scotchlite™ (3M product) adhesive, sometimes with a designed screened in, laminated to the metal plate.  A precursor to this, for the most part, was reflectorized paint on the raised surfaces of the plate.

The first attempt at reflectorization was the reflective paint.  This was achieved by sprinkling microscopic glass beads onto the paint before it had a chance to dry.  The beads would stick onto the paint, providing a rough texture and the reflective surface.  Ontario was the first to try this method, on the 1939 Doctor's plates, however it was a trial basis only as no other Ontario plate was made this way.   Only Alberta put this method to general use on its plates in the 50s and from the mid 60s to mid 70s.  Prototypes of this genre were made in PEI in 1966.  Today it is not very popular as the glass-beaded paint has a tendency to get dirty or the glass beads themselves wear off.
 

This Ontario Doctor's plate  was Canada's first attempt at reflectorization

The Scotchlite reflectorization method came later as it was first introduced in 1958 on a trial basis.   There were a few
technical problems in those early years, mainly getting the Scotchlite to adhere properly to the metal base.  Moisture had a tendency to get under the adhesive causing unsightly rust and corrosion within a year or two of normal use.  In order to refine the manufacturing technique, some provinces made test plates to be distributed to some registrants.  Others made one or two examples and used them on government owned cars to see how they would weather over the year.  Today, most plates are made using this reflective adhesive, proving itself as the superior technology.

	The first attempt at Scotchlite reflectorization in Canada occurred when Saskatchewan made their first 1,000 plates in '58 and '59 reflective.  They were satisfactory in their salt-free climate but since they were annual it is difficult to say how they might have survived over several years.  Because of the additional costs, they decided not to issue reflective plates on a general basis until 1970.
	PEI made the first attempt at making a multi-year reflective plate.  In 1966 and 1969 the first 1,000 plates were made reflective as an experiment.   Unfortunately they  did not hold up well at all in PEI's salty air, as this example illustrates.  You can see where moisture had gotten under the Scotchlite and caused serious corrosion.  A switch to aluminum might have been more successful, but no doubt would have added to the cost of production.

Paul Wingert: '58 Sask refl.
eBay: '58 Sask
ALPCA archives: '39 Doctor

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