The Creation and Development of Reflective Signs

On the roads and highways of today, signs are everywhere.  They tell us how fast to go, when to stop, how far to our destination, danger ahead, and a variety of other very important messages.  Without these signs, the roads of the world would be much more dangerous than they already are.  We depend on these signs for guidance and information as we drive in the daytime, and even more so at night.

In  the daytime, we see  signs clearly because of a phenomenon called scattered or diffused reflectivity. This is when light hits an object and reflects in every direction.  This type of reflectivity is natural, and is what allows our eyes to see the world in full color and clarity.   The problem is, at night, there is very little light to reflect off of anything, so the world goes dark.  Unfortunately, in the early 1900’s, road signs also went dark, making night time driving hazardous.

The Development of a Solution to Night Time Sign Visibility

In the early 1900’s, inventors began working with glass spheres and mirrors in an effort to create what we now know as retro reflectivity. Retro meaning to go back, and retro reflective meaning to reflect light back to the source.  It is interesting that both glass spheres and mirrors were experimented with around the same time, because today, both methods are still used to reflective light.

In the 1920’s, reflectivity was officially added to signs through the use of large glass beads or cats eyes embedded into the sign itself in little divots.  If you look up vintage stop signs you can see these devices being used to spell the word stop, or to outline a sign.

A device called a Cataphote Reflector was invented in 1927 by Percy Shaw.  It incorporated a glass sphere in a metal holder. This device gave users the ability to add reflectivity to anything they desired.  Mr. Shaw’s invention was used on everything from signs to road markers. (marking center line of the road)

In 1928, around the same time that Mr. Shaw was patenting Cataphotes, Jonathan Cass Stimson was inventing the cube corner reflector.  His company, Stimsonite, is credited with the creation of this device, and his technology is used to this day in car tail lights and reflective road markers.

In the 1930’s, Potters Beads began manufacturing perfectly round, clear glass spheres.  These were originally intended to be used on cinema screens, and painted highway lines to make them reflective.  To this day, Potters Beads are still used to make road markings reflective, all over the world.

In 1937, the 3m company, developed a way to embed glass beads into a flexible backing.  Their original intent was to create reflective road stripes using this method.  Durability was an issue with the invention, so the film was further developed to be used as a way to make signs reflective.  This would be the first development of what we now know as reflective tape.

From 1937 to 1947, 3m continued to develop their new reflective sheeting.  In 1947, the product was brought to market and branded as Engineering Grade Reflective Sheeting or Tape. 3m’s new film quickly became the industry standard for sign reflectivity world wide and is still used to this day on signs around the globe.

In 1963, the Rowland Brothers, using Stimsonites cube corner technology, invented what we now know as prismatic reflective sheeting.  Other companies, including 3m, picked up on this new invention, and today, prismatic sheeting has become the standard for signs, especially on busy interstates.

For most standard non highway reflective signs, engineer grade is still used extensively.  Engineer grade comes in the most colors, and is the best material for cutting with a computer controlled plotter.  This is the film we use for our custom retro reflective signs.  It can be seen for several hundred feet, and is nice and vivid.