Most cold foil printers are producing at speeds between 12.000 and 15.000 sh/hr to apply cold foil, inks and coatings in one pass. Most hot stamping machines are producing at speeds between 6.000 and 8.000 sh/hr.
Offset plates for cold foiling are unexpensive and they are available very quickly. Clichees are expensive and most of the times outsourced to special companies. Also production of cliches are time consuming.
Because a die is not necessary for cold foiling, production time is cut down considerably. The cold foil adhesive is printed onto the substrate in the design to be foiled just as quickly as regular ink would be. Changing a job in an offset machine, is a matter of minutes. In a Hot Foil press average between 0,5 and 8 hours.
Hot foils come in a growing number of shades, however the cold foil process allows the broadest range of colours. This is possible because the colour is printed on top of the metallic layer (In most of the cases silver) on the substrate.
Because the additional step of hot foiling in the production process is becoming obsolete your finished product is available much quicker and the time & cost involved in storing semi-finished products is reduced. If your customer is requiring an additional embossing for the cold foil it can be done in the die-cutting machine at a much higher speed than with hot foiling. The advantages are obvious – Higher output of your die-cutter, reduced space & time for storing semi-finished products, shorter delivery times and quicker invoicing to your end-customer. This means more value added to your production process.
The most suitable substrates for cold foil are coated stocks. Matt coated papers are suitable as well but should be tested before. The majority of uncoated stocks can’t be used in cold foil without further treatment before production. The substrate grammage is ranging from 70 g/m2 to 450 g/m2.
In the first printing unit an adhesive is applied to the substrate in the design that is to be foiled. In the pressure nip of the following printing unit the cold foil web is in contact with the substrate and the metallic layer of the cold foil is transferred to the areas of the substrate where the adhesive has been applied before. The areas without glue will not be metallized and the metallic layer will remain on the polyester backing film.
A heated die, or stamp, of the design to be foiled is mounted in the stamping machine above the substrate. The foil runs between the substrate and the die, so that when pressure is applied from the die onto the paper, the foil is fixed to its surface. Because pressure is a main ingredient of hot foiling, the foil has dimension and a unique haptic.
These two methods used to apply metallic effects in print-cold foil transfer and hot stamping-differ in their unique effects and in productivity. Cold foil transfer is more effective due to the inline process where metallic effects are applied in one pass with the overprinting inks while hot foil can deliver haptic effects like relief embossing. Many cold foil printers from packaging are combining both technologies. They are applying cold foil in the printing press. When die cutting their products they add a blind embossing to the cold foil areas. By doing so they achieve a 3 dimensional cold foil result without having to slow down the die cutting machine due to hot-foil application.