Three numbers and one of them is yours
Ink volume for a single print is area times coverage times film thickness. Area you can measure with a ruler. Coverage you can estimate closely enough by looking at the separation — a solid rectangle is near 100 per cent of its bounding box, halftone shading is somewhere in the middle, thin line art is often under 20. Film thickness is the one that has to be measured on your own press, because it is a property of the mesh, the tension, the squeegee and the stroke rather than of the ink in the container.
The honest way to get it is to weigh. Weigh a stack of blanks, print them, let them cure, weigh them again, and divide the difference by the printed area and by the ink density. That gives a cured deposit; wet is thicker. It is a tedious afternoon and it replaces a guess that multiplies every ink number you will ever quote.
Why the underbase is the expensive part
An underbase is not a shade of white sitting under the art. It is a full layer, printed at at least the coverage of everything on top of it, and often at more because it has to be opaque. Adding it to a three colour print takes the piece from three layers of ink to four. The calculator shows the underbase as its own row for exactly this reason: it is the largest single step in the ink line, and it is the step that gets left out when a job is quoted off the colour count.
What this page deliberately does not do
It states no deposit, no mesh count, no coverage rate, no cure schedule and no ink price. Every one of those is a property of a product and a press, and the ink data sheet in your building is the authority on the ones that concern the ink. This page multiplies the numbers you supply and converts the units.
Related
Feed the per-piece figure into the setup and break-even calculator, where it sits against setup and press time. The screen itself is costed in the emulsion and reclaim cost calculator. For materials bought in packs and consumed per unit generally, the craft material cost per unit calculator takes the same shape.
Questions people ask
Should I use the wet deposit or the cured one?
Use whichever matches what you measured, and be consistent. Ink is bought and consumed wet, so a wet deposit is the more direct answer for a mileage question. If you measured a cured film by weighing shirts, that number is thinner than the wet film because solvent or water has left, and using it will understate how fast the container empties. The field is labelled wet for that reason.
Why is the coverage percentage separate from the image size?
Because ink follows the inked area, not the bounding box. A 10 by 12 inch outline drawing and a 10 by 12 inch solid block are the same size and use wildly different amounts of ink. Splitting them lets you keep the image dimensions you actually have and put your judgement into one number you can revise when you see the separation.
Does a print-flash-print really double the ink?
In this model it does, because the stroke count multiplies the deposit and the calculator has no way to know that your second stroke lays down less than the first. In practice a second hit onto a flashed layer often deposits less than the first, since it is printing onto a cured film rather than into fabric. If you have measured that difference, express it by lowering the deposit rather than by lowering the stroke count.
The waste percentage feels arbitrary. What belongs in it?
Ink that leaves the container and never ends up on a garment: what stays in the screen when you scoop back, what goes onto rags and into the wash tank, what dries on the edge of the container, and what you mix and never use. If you buy ink by the gallon and reconcile it against printed pieces once a quarter, the gap between what the arithmetic says and what actually left the shelf is this number.
Can I use this for water based or discharge ink?
The geometry is the same, so yes for volume. The measured deposit will be different, and so will the shrinkage between wet and cured, which is exactly why the deposit is a field rather than a constant. What this page cannot do is tell you how any of those inks behave on a given fabric or how they need to be cured, and those answers come from the data sheet, not from arithmetic.