Ink coverage: the number you quote against

What is actually shown

One row per ink: the area it covers on the artwork. A total underneath, across every plate. Below the table, the size all of it was computed from, which you can correct right there.

That last detail matters more than it looks. A customer’s file is very often not at print size, and an area computed from the wrong size is a lie with a unit attached. Correcting it here corrects the whole job, because there is one size and the films carry the same one.

Why the total is bigger than the artwork

This is not a bug. Artwork 30 by 40 centimetres is 1200 cm², and the total may read 2000 or more.

Because inks sit on top of one another. An underbase covers everything printed above it, and that same patch is counted once for the base and once for every ink over it. The total is not the size of the sheet. It is the area that goes through the press across all passes, which is what ink and time actually track.

If the total is roughly double the artwork, you most likely have a solid base under everything. That is the first place to look for savings.

The count is geometric, and that matters

What is measured is the area where the ink’s tone is above zero. The area the ink touches, not the mass of ink that will land on it.

For a solid those are the same thing. For a halftone they are not: an area at 30 percent tone counts whole, although ink lands on roughly a third of it. So on artwork with large fades the figure overstates consumption, while on a real screen the dots spread, which pulls the other way.

The practical reading: treat it as a yardstick for comparing two versions of the same job, not as a consumption figure in grams. Grams need your own correction, and the only way to get one is to weigh the bucket before and after a run.

Turning area into money

Once for your shop, then arithmetic.

1. Weigh a run.Bucket before, bucket after, divide the difference by the total printed area. That gives grams per square metre for that ink through that mesh.
2. Price the area.Cost per kilo times that consumption gives the cost of a square metre of coverage.
3. Take the total from the table.It is in square millimetres or centimetres. Convert to metres and multiply.
4. Add the screens.Every ink is a screen: emulsion, exposure, washout, registration. That part does not scale with area, and on short runs it dominates everything else.

Which is where the real pricing rule comes from: on a run of twenty you are selling screens, and on a run of a thousand you are selling area. One extra ink on a short run costs more than all the ink spent on it.

Where the savings are

• The underbase. Almost always the most expensive plate, because it covers the sum of all the others. Following coverage instead of solid cuts it noticeably.
• The base threshold. A sparse halftone does not need white under it. Raising the threshold takes it out of there and softens the print at the same time.
• The ink count. Look at the row with the smallest area. If an ink covers one percent of the artwork, ask whether it earns a screen and a registration of its own.
• Tolerance. Less tolerance leaves more fabric open, and the table shows it at once: every row falls.

FAQ