Colour and ink checks

These checks look at how the artwork is built for the press: its colour spaces, how much ink it lays down, what overprints, and which spot inks it uses. Technical inks (die, crease, glue …) and finishing inks (varnish, foil, white …) are recognised by their names and are never counted as printing ink (see what counts as artwork). Each table shows a check's settings in the five presets.

Colour#

Colour spaces#

Colour the press does not print directly: images, text, vector artwork, gradients and transparency blending in the spaces you flag. "RGB image.", "RGB colour used for text.", "Transparency blends in RGB: the flattened result is converted from it." Each image is one finding however often it is placed; other colour is one finding per page for each kind (vector, text, gradient, blending) and colour space.

• Flag: the spaces to flag, any of RGB, Lab and Grayscale. ICC-based and indexed colour count as the space they are based on. Flag none and the check finds nothing.

Total ink coverage#

The highest sum of the process inks anywhere in the artwork (the total ink coverage), such as 100 % cyan plus 90 % magenta plus 80 % yellow plus 100 % black, 370 %. Too much ink dries slowly, sets off and cracks on folds. "Ink coverage reaches 342% (limit 320%) over 1.2% of the page." The locations are the areas over the limit, the worst first.

Coverage is measured from the file's own separations, with technical and finishing inks switched off, and averaged over squares of 0.5 mm, so anti-aliased edges and hairlines don't count. Only the artwork area counts: colour bars and registration targets in the slug print on every plate by design.

• Maximum: the highest total allowed, 100 to 400 %.
• Count printing spot inks: off, only cyan, magenta, yellow and black count; on, printing spot inks count too.

Lightest tint#

Tints lighter than the press's smallest dot drop out or print unevenly, typically on flexo. "Tints lighter than 3% (lightest 1.5%) can drop out on press." Flat colours of fills, strokes and text are checked, down to 0.1 %; images and gradients are not.

• Lightest tint: the lightest tint allowed, in percent of each ink.

Overprint and knockout#

An object that knocks out clears the colours beneath it; one that overprints prints on top of them. Both can be right or wrong, so these four checks look at the cases that matter.

Overprint#

Objects set to overprint, which print on top of the colours beneath instead of replacing them: "Objects set to overprint." Often intended, it can also make a colour change or vanish, so the presets list it as a note.

• Ignore black: on, solid black (black ink alone at 95 % or more) that overprints is not flagged: that is normal practice.

White overprint#

White objects set to overprint disappear on press: "White objects set to overprint: they will disappear." Every preset makes this an error. It has no settings.

Black overprint#

Solid black text and thin black lines should overprint: knocked out, the slightest misregistration shows a white or coloured halo around them. "Black text up to 12 pt knocks out: overprinting avoids halos from misregistration."

• Text up to: black text this size or smaller is checked. 0 skips text.
• Lines up to: black strokes this width or thinner are checked. 0 skips lines.

Technical lines overprint#

Die, crease and other technical lines must overprint: knocking out, they punch a white line into every plate beneath them. "Technical lines (Dieline) knock out the artwork beneath: set them to overprint." It has no settings.

In the 1-up editor this finding offers Fix: overprint technical inks, which turns on Overprint technical inks on the editor's Tools tab; apply it to the print-ready file there (see The Preflight tab).

Spot colours and registration#

Spot colours#

The spot inks in the file. These findings are about the whole file, so they have no page. Names are compared without regard to case, spaces, hyphens and underscores.

• Expected spots: the spot inks the job should have, comma-separated, such as PMS 185 C, Gloss Varnish. Each one missing is a finding: "Expected spot colour PMS 185 C is not in the file."
• Flag unexpected spots: with expected spots listed, every other printing spot ink is a finding. Technical and finishing inks are never unexpected.
• Most printing spots: more printing spot inks than this is a finding, which names them. 0 turns it off.
• Require a die or cut ink: the file must have a die, a technical ink or a technical layer; without one, "No die or cut line ink was found." is an error.

Whatever the settings, two spot inks that look like the same ink ("PMS 185 C" and "PMS 185 U") and one spot ink defined with different colours in different places are findings too.

Registration colour#

Registration colour prints at 100 % on every plate. It belongs on crop and registration targets outside the trim, never in the artwork: "Registration colour (every plate at 100%) used inside the trim." Anything in registration colour more than 1 pt inside the trim or the die is flagged. It has no settings.

Transparency#

Objects with an opacity below 100 %, a blend mode other than Normal, a soft mask, or in a transparency group. They print correctly in a workflow that handles transparency (PDF/X-4) or once flattened, so the presets list them as notes. A page that is itself a transparency group is always a note. It has no settings.