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Metallic printing inks
require a different discipline than running conventional inks. Persons
specifying these inks should understand their unique qualities and press
conditions must be carefully monitored during printing. The following notes
will help you achieve the best results when printing with PANTONE Metallic
Colors:
Leafing is the special characteristic of metallic inks where the metallic
particles float or "leaf" to the surface, thus providing the
"metallic" effect. The length of drying time affects leafing; if an
ink dries too quickly, such as with ultraviolet inks, maximum leafing may not
occur. Other factors which affect metallic lustre include paper and ink film
thickness.
Special care must be taken when varnishing metallic colors, especially with
ultraviolet or water-based coatings. It is recommended that tests be made to
ensure correct interfilm adhesion.
Pantone recommends using a quality coated paper for optimal results. Use of
other stocks may result in loss of color, brilliance and metallic sheen. If a
stock other than coated is used, a press proof should be seen before producing
the piece.
For accurate reproduction of color, PANTONE Metallic Color blends should be
mixed as close to presstime as possible.
As metallic colors are opaque, they should be printed first in printing
rotation. When printing systems other than sheetfed offset are used, formula
modification may be necessary. This is especially true for web offset and
ultraviolet inks.
To maximize the color, metallic duotones should be printed with the metallic
color first as the full image halftone, with black used as an overprint to
enhance the image. The metallic color should be printed first with the black
used as an overprint.
When printing a screen tint of a metallic color, a decrease of metallic lustre
can be expected, especially in the lower screen values. At the higher values,
excessive dot gain may occur, causing the screens to fill in. Reduction in ink
film thickness may be necessary to keep screens open and reverses clean. In
order to optimize the effect of a metallic screen tint, a slightly coarser screen
percentage could be used.
Some of the many variables which may affect color reproduction include:
- Variations in paper color, quality and texture
- Ink color accuracy
- Plate quality
- Condition of equipment
- Printing process used
- Degree of dot gain in film, plates and on press
- Using outdated color books
- Ink film thickness (density)
- Position in press layout
- Ink/water balance
- Press color control
- Pressmanship
- Viewing conditions
- Leafing
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