| The development of modern cold stamping foils | | | | slower the running speed. Since printers want the |
| originated with the simple cold foils devised as a | | | | lamps set in a fixed position, and not changed around |
| dieless technique for applying a metallic finish to self | | | | for each type of job, all curing is generally carried out |
| adhesive labels produced on reel to reel printing | | | | through the foil than through the film being printed. |
| presses. There are many benefits of this process, and | | | | Given that this can be done, then cold foiling is much |
| some disadvantages, although cold foiling has | | | | faster than hot foiling, and of course there is no need |
| progressed a lot since then. | | | | for a die, thus saving not only on die-cutting costs but |
| The benefits in reel to reel printing are obvious. If hot | | | | also on energy. A very appropriate saving these days. |
| foiling is carried out in-line at the end of the printing | | | | So why are all reel to reel jobs not blocked using cold |
| process, then the press speed is limited by the foiling | | | | stamping foils? Mainly due to the quality. Cold foiling is |
| speed which is relatively slow. If the printing was | | | | generally not as brilliant as hot foiling, and also most |
| maintained and the foil applied as a separate pass, | | | | stamping foil manufacturers offer a very limited range. |
| there is a corresponding cost impact. Furthermore, the | | | | They have also tended not be very print receptive. If |
| cost of hot foil dies is relatively high compared to a | | | | the overprint is small enough, it can adhere, though the |
| printing plate or sleeve and energy is needed to heat | | | | cold foil surface tends to be fairly low in surface |
| the die. | | | | energy (low dyne level). Larger printed areas tend to |
| Reel to reel cold foiling involves printing a UV curable | | | | have poor scratch resistance and tape adhesion, |
| adhesive in the foil design needed, laminating the foil to | | | | though many customers accept this in return for the |
| the adhesive through a nip, curing the adhesive with | | | | lower costs. Modern developments, however, are |
| UV lamps and separating the foil from the printed web. | | | | tending to overcome these problems though truly |
| The foil that is removed from its carrier film is in the | | | | overprintable cold foils are very difficult to find and |
| design of the printed adhesive, since that has been UV | | | | depend very much on the type of ink being used. |
| cured and so adheres to the foil. | | | | Modern cold foil developments include sheet fed offset |
| By using a cold foil, the speed is limited only by the | | | | litho applications, whereby the adhesive is applied by |
| strength of the UV lamps or the optical density of the | | | | traditional oxidation drying offset, and then the silver foil |
| foil. The aluminium layer in the foil has to be thinner than | | | | overprinted with oxidation drying offset transparent |
| that normally used in a hot stamping foil to allow | | | | inks to produce an attractive coloured metallic effect. |
| sufficient transparency to the UV light. True, this is | | | | This process is currently patented. Further |
| irrelevant when the foiling is carried out directly to | | | | developments involve offset UV adhesives and inks, |
| transparent films since the light can be directed through | | | | though the adhesion of the UV ink to the foil surface is |
| the back of the film onto the adhesive, but this is | | | | still an issue here. |
| frequently not the case. The foiling is often carried out | | | | The volumes of cold foil being used world wide are |
| over an opaque white ink which can be silk screened | | | | increasing at a rapid rate, and much of this is in the |
| onto to the label prior to the adhesive and then the foil | | | | offset field, where the major European printing |
| applied. This places an opaque layer between the film | | | | machine suppliers are offering purpose build equipment, |
| and the foil, so that the beam has to pass through the | | | | and add-ons that can be retrofitted to a printer's |
| lacquer layer or top coat of the cold foil. | | | | existing equipment. The printing quality is improving as |
| The UV beam passes through the lacquer and | | | | more development work is carried by the hot stamping |
| aluminium layers to reach the adhesive, so the | | | | foil producers, and the quality modern cold stamping |
| aluminium must be as transparent as possible. The | | | | foils is rapidly approaching that of hot foiling. |
| more opaque it is, the more lamps are needed or the | | | | |