Refractive or micro-etch are two common terms used to describe the application of refractive foil stamping. Although refraction is not a new process, it has continually grown in popularity. A refractive foil stamped image is created with a specially engraved die (usually brass). Very thin lines are etched into the engraving to demonstrate texture and detail in the foil stamped image. The foil used in refractive stamping is standard hot stamping foil (usually metallic) and is no different than foil used in a flat stamping application. What are the different choices available with refractive foil stamping?
Most engraving companies that offerrefractive dieshave a library of standard patterns that can be etched into the die. This is most commonly used on lettering and simple line art. This is the most inexpensive method of utilizing refraction.
A custom refraction is more labor-intensive than using a standard pattern. The engraver starts with standard patterns, but actually places these patterns at different angles and in many different areas within the image. This is usually accomplished through a graphic design computer programme. The result is a beautiful, extremely detailed foil stamped image that almost moves as you look at it under a light.
Refraction and overprinting
This might be the most interesting and dramatic application of hot stamping foil available. Refraction combined with overprinting has become very popular for paperback books, greeting cards and packaging applications. This is accomplished by first foil stamping the image with a refractive engraving, usually using a metallic silver foil. Then the piece is sent to a printer to overprint the foil stamped area with translucent four-colorinks.
If overprinting refraction is used, what precautions should be taken? This is an area where communication between the foil stamper, printer and designer is extremely important. The registration of the four-color lithography over the foil is very tight. The die maker, the foil stamper and the printer must use the same 100% film or digital file to keep everything in a register. In addition, the foil stamper must communicate with the printer to run the guides and grippers of both the foil stamping and printing press on the same side of the sheet to maintain registration. The challenge is that with most tight registration jobs, the foil stamping is registered to the printing. In this case, the printing is registered to the foil.
Utilizing a coated or cast-coated paper stock is most desirable to provide the best look for the refractive foil and to ensure the best relationship between the foil and inks. The ink must be wax free to eliminate any adhesion problems and it must dry by oxidation opposed to absorption because the foil stamped refraction will not allow the ink to absorb into the stock. In addition, the ink must be translucent to allow the foil and refraction to shine through the ink. Lastly, not all hot stamping foils are over printable. It is recommended to consult your foil supplier and make sure an over printable foil is used.
How should artwork be prepared for refractive dies?
The ideal art is to utilize a digital format due to registration issues and the ability to utilize the file to create custom refraction. However, traditional art boards or films are usually acceptable. If a film is provided, it should be 100% of the size and indicate the upside of the image (no halftones). If an art board is used, it must be 100% of the size with clean crisp black and white images (no halftones). A digital file needs to be saved at 200 to 600 dpi, utilizing vector files to eliminate potential font problems.
It is important to indicate what areas one must refract and what areas are to be keptflatfoil stamped. It is possible to apply refraction in certain parts of the image and leave certain areas flat stamped within the same die. If a standard pattern is being used, the specific pattern number and/or name should accompany the artwork.
Advantages of refractive foil stamping
Refractive foil stamping allows one to create detail and texture in the image without embossing the paper. The thin refractive lines can actually create the illusion of movement in the image that cannot be done with other foil stamping methods. Refraction with holographic foil is an inexpensive alternative to creating a custom hologram.
Special ‘on press’ instructions for a refractive die
A refractive die works very similar to a standard flat stamp die. It does require more pressure to ensure the etched lines are stamped properly. A rule of thumb for flat stamping is to apply one tonne of pressure for a square inch of stamping area. With refraction, it is recommended to increase this to two tonnes of pressure for a square inch.
What is the cost of a refractive die?
The most cost-effectiveway to utilize refraction is to choose a standard pattern. This is usually charged by the square inch by the engraver and is easy to figure and budget. Custom refraction is usually quoted by each job based on the size of the image, number of patterns used, the complexity of the image and desired effect. If proper planning and communication is used, adding refractive foil stamping can add real pizzazz to a foil stamped image without adding exorbitant costs to the project.
This article was reprinted with permission from the May/June 2003 issue of Inside Finishing magazine. Jeff Peterson is the executive director of the Foil Stamping and Embossing Association located in Topeka, Kansas. For more information on Inside Finishing or the Foil Stamping & Embossing Association, visit www.fsea.com. Jeff may be contacted at 1-785-