John D. Rutoskey suggested what is probably one of the best ways to
make a single or a small number of decals by using a ruboff transfer.
To make the job easier on yourself, have the graphics house put _all_
the colors on the transfer for you.  They put the pigments on the back
of the transfer paper (in reverse) with the 'front' layer applied
first, just like the old varnish decals.

The last (bottom) layer of color is often white to make the colors
bright when the decal is applied to a dark surface.  Also, the last
layer can be metallic silver or gold.  Either of these should be behind
the _entire_ artwork, not just the places that appear 'gold' when you
see it from the front.  The real last layer is an adhesive.

When I worked in the design department at Xerox, we used to make all
the prototype model graphics using this technique -- even entire
control panels, with all the text and symbols.  We could get better
color matches than we could on the real machine colors in production.

Have the graphics house make several, as the additional copies are very
cheap, especially if several will fit on one sheet.

Craig Smith