SMART INVESTOR

Dot Gain

Dot gain is not a fault of web offset printing, but rather a characteristic. The dot gain can to some extent be accommodated in production but there are some things, outlined below, that can help.

All material should compensate for dot gain of up to 15-20% in the 50% dot area. Ensure midtones are lighter and have more contrast to compensate for the above dot gain.

Grey Balance

Maintaining Grey balance throughout the separation is extremely important for quality four-colour reproduction.

Separations without neutral Grey’s will reproduce with perceivable colour casts on press. As a general rule for magazine reproduction, Grey balance requires slightly more cyan relative to less amounts of magenta to yellow.

Four Colour Mono Images

Four colour mono images have a tendency to reproduce with colour and tonal shifts and often the result differs to the original proof. We suggest using an achromatic, or GCR, set-up. Increasing the use of black and reducing the other three colours will result in a more neutral image that will reduce the risk of tonal and colour shifts on press.

Total Saturation

The total saturation for process colour material should range from 280-300%. This helps compensate for dot gain and allows for maximum shadow detail with minimum ink set-off.

Saturation exceeding 300% will not result in darker shadows on magazine stock. It simply leads to excessive set-off and causes shadow areas to plug; thus reducing printed shadow detail.

Any single colour not intended to print solid should not exceed 80%. We recommend that large areas of black be at least two colour (100% black, 60% cyan) or four colours.

Typefaces

San serif typefaces are the best choice for reproduction. They reproduce easily with desired readability. Typefaces with thin or delicate serifs and strokes should be avoided. Extremely fine strokes can drop out, while thick strokes can plug on the press.

Because of the ink and stock relationship, small type tends to lose definition on the press. Coloured type or solid backgrounds can print using a single colour at 100%. Should a second or third colour be required, these extra colours should be limited to 95%, keeping within the total ink limit of 300%. This will allow the ink to trap on the press and result in a consistent and balanced printing.

For legibility reasons, consideration should be given when attempting to reproduce type as a light screen tint. For best results, avoid screening type styles with a fine to medium weight and those with serifs.

For optimum results it is suggested that type not overprint a background screen (tint or ghosted image) greater than 30% visual density. This allows for dot gain and provides necessary contrast between text matter and the background image.

Typefaces in reverse

• Typefaces in four colours should be sans serif and bold, no smaller than 10pt.
• Type with serifs or screens, reversed out of a four colour image or colour, should be 10pt or greater in size, otherwise the material will not be accepted. This allows for slight variances in register while maximizing legibility.
• Any reverse type should be limited to two colours maximum. For contrast and readability, reverse type should not be positioned within screened areas less than 50%, or in yellow or other light coloured backgrounds.

Line Art

• Minimum width 0.125mm (0.005 inch) with a maximum of two colours overprinting.
• Avoid line art less than 1 pt.