What Is Half Tone for Letterpress Printing?

Halftone printing allows for variances in tones.

The halftone method of printing was invented to allow for the printing of photographs. Unlike common mechanical printing presses, such as the newspaper press, the halftone method prints various shades and continuous tones that are required to reproduce photographs.

Function

The halftone process converts tones into dots of varying size. The eye can't distinguish the tiny dots, so it is tricked into seeing a solid color. The larger the dots, the darker the color appears.

Size

Halftone screens, which create the sizes and variance of the dots, are measured in number of lines per inch. The more lines there are, the better the quality of the reproduction.

Measurement

Graphic Touch Letterpress recommends a maximum of 100 to 120 dots per inch (dpi) when using magnesium metal plates. However, traditional printing processes can hold 150 to 300 dots per square inch. Coarse halftones can be used to create an aged look of a photograph.

References

• Ted's Photographics: The Science of Photography - Halftone Reproduction
• The Graphic Touch Letterpress Company: Tool Box