Halftone & Special Effects Process

1. Halftone & Special Effects Process Halftones Duotones Posterization

2. Halftone & Special Effects Process Halftone: comes from an old hand-engraving process that involved breaking the image up into quarter tones, halftones, and three-quarter tones. Contact Screen: is a series of uniform vignetted (soft) dots mounted on a flexible support base. Halftone contact screens can be MAGENTA or GRAY in color. Tint Screen: is used in the platemaking process to create the uniform tone pattern and contains a hard dot structure that is specified by a dot percentage: Highlight = 5-10% in size. Midtone = 30-70% in size. Shadow = 90-95% in size.

3. Halftone & Special Effects Process Halftone Process: the procedure of converting a continuous tone original into a pattern of dots. Because of the nature of photographs, they can’t be printed on presses. So to print photographs, the photo must be converted to a halftone containing a dot pattern corresponding to the many shades in the photo. Halftone Reproduction: the process of printing a continuous tone image using the same one-color-per-plate printing process. Full color images require four plates to print the process: Yellow, Magenta, Cyan, & Black….CMYK Procesc Printing

4. Camera Copy Line Art: A drawing with no grays or middletones. Traditionally, black lines on white paper. Mechanical Shading: Similar to line art, but has finer details and is usually intricate in nature. Continuous Tone: an original that has not been screened, and has infinite tone gradiations between the lightest highlights and the deepest shadows. Reflection Copy: an original that is opaque. It reflects different amounts of light from the different tone values. Transmission/ Transparent Copy: an original that allows light to pass through it.

5. Camera Copy Prescreened Images: Camera copy that already contain a screen or dot pattern. Moiré Pattern: A visually undesirable dot-exaggerating effect that occurs when two different screen patterns are randomly positioned or superimposed.

6. Evaluating Continuous Tone Originals Highlights: the whitest tonal value. Midtones: the gray tonal values. Shadows: the darkest black tonal value. Density: the light-stopping ability of a material--it’s ability to hold back or block light. Densitometer: an electronic instrument that uses a photocell to measure the amount of light reflected from or passing through different tone values.

7. Evaluating Continuous Tone Originals High-Key Photograph: contains the most important details in the highlights, or lighter tones. Low-key Photographs: contains the most important details primarily in the shadows, or darker tones.

8. Color Separations Color Separation: the process of using red, green, and blue filters to divide the many colors of an original image into the three process colors (yellow, magenta, & cyan) and black. Screen Angles for Color Reproduction: color reproduction uses four halftone negatives, each representing a different screen angle. Different angles are used to eliminate or minimize the undesirable moiré pattern. Below are listed the different angles used for each color: Black Screen Angle = 45º Cyan Screen Angle = 105º Magenta Screen Angle = 75º Yellow Screen Angle = 90º

9. Duotone Techniques Duotone: a special effect that consists of making a two-color halftone reproduction from a single color image. There are four different classifications of duotones: • Two-impression black duotone *(double-black) • One color plus black duotone • Color on a second color duotone • Fake duotone

10. Posterization Posterization: the technique of changing a black-and-white, continuous tone photo into a multicolor or multitone reproduction. There are four different classifications of posterization: • Two-tone Posterization • Three-tone Posterization • Four-tone Posterization • Multiple-tone Posterization

11. Tone Line Process Tone Line Process: process used to convert continuous-tone originals into line reproductions that resemble pen-and-ink sketches or other fine-line drawings. This process removes the gray tone values.