There is no doubt that hard vinyl tapes can be and have been
the workhorse for many printers for many years. They are certainly the lowest
cost and the original modern mounting tape but if you are printing anything
other than just solid and line work they will do little to enhance your print
quality.
Softer tapes are usually of a foam construction and come in
a wide variety of densities. The choice of density depends mostly on the
graphics that you are trying to print and help minimize dot gain and still
achieve good solid print as well. These tapes have a much more complex
construction than the basic solid vinyl tapes and also come with a combination
of adhesives and liners that can help dramatically improve your print quality
and the actual mounting and demounting of your printing plate.
Many thicker cushion mount tapes are used to build up
cylinder diameters where plate caliper has been reduced, which is becoming more
common as printers move to thinner plate technology but do not want the cost or
rebuilding or replacing their existing plate cylinders. There are a wide
variety of thicknesses that will suit all plate, sleeve and print cylinder
combinations. There are tapes made specifically for fiberglass and other carbon
fiber sleeves again to help ensure good repositionability and to minimize the
amount of adhesive residual on the sleeve when the plate is removed. This
applies the same for steel print cylinders as well. Many liners now have a grid
pattern or other patterned structure to ensure that air is not trapped under
the tape when it is being applied to the cylinder.
Softer cushion tapes not only help reduce dot gain when the
plate is being compressed but also help mask other small defects found on most
older plate cylinders and sleeves. That said, you need to ensure that the tapes
you buy have a consistent caliper. The better tapes are ground to ensure
caliper control; this is something you should check with a micrometer from time
to time. A good cushion tape should have good compression and good recovery
throughout your print run. Your vinyl tape has little or no give other than the
thickness of adhesive and certainly has no recovery.
Because of their superior engineering, soft/cushion tapes
are generally more expensive than vinyl tapes just as your supplier has said
but in my opinion are worth the extra cost up front based on the benefits that
you will see throughout your print runs and extended plate life that you will
also be able to enjoy.
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