METALLIC INKS ON LETTERPRESS In general, metallic inks do not offer the same shine on uncoated paper that is achieved on coated paper. Metallic inks also have the distinct advantage of being opaque rather than translucent on colored papers. Metallic inks for letterpress should be observed in the Pantone UNCOATED swatch book since we are matching our prints on uncoated stocks. Things like stock color, type of material and surface finish the paper will play a role in the final sheen of the printed ink.
In regards to metallics, good options to keep in mind for achieving more sheen are:
Print a double hit - This may work in certain instances but is subject to the artwork. Type and artwork details generally should be above 8pt in size. This will add a bit of press time and cost to the project.
More Ink Density On Less Detailed Artwork - We can achieve a double hit of ink OR a much thicker single hit of ink with less detailed artwork. A large area of color with out small details can be printed with a more generous amount of ink.
Print On A Smoother Stock - The ink will stand on the surface of a smoother finish uncoated stock. Stocks like Lettra and most cotton fiber paper is fairly toothy in surface finish. Ink is absorbed into the surface rather than standing up on the surface.
Use Straight Metallic Inks VS Mixed Colors - Straight up silver or gold will have the most metallic properties. As they are mixed together and become coppers and bronzes or other pantone colors the shimmery quality of the ink becomes even more minimal, especially on an uncoated stock.