Tin foil hat radio with a metal bucket. The AM radio is completely inside a metal enclosure. This leads to a noticeable reduction in signal strength received by the AM radio. The efficiency of a metal enclosure in blocking electromagnetic radiation depends on the thickness of the foil, as dictated by the "skin depth" of the conductor for a particular wave frequency range of the radiation. For half-millimetre-thick aluminum foil, radiation above about 20 kHz (i.e., including both AM and FM bands) would be partially blocked, although aluminum foil is not sold in this thickness, so numerous layers of foil would be required
Cold foil printing or offset sheet-fed printing. It can be applied precisely with high resolution, even for fine structures such as raster gradients and thin lines. Typeface is legible from about 5 points upwards and has excellent edge definition. Cold foil printing needs smooth surface substrates for excellent image quality. As the cold foil market evolves, major players in the printing industry are finding ways to make the process even more cost-effective. By indexing cold foil, printers can reduce foil waste, reduce their presses' downtime, and in turn maximize their presses' efficiency. Cold foil is most commonly used on products that call for