Seshat 1.8.3 measures ink where it prints, down to small shapes, and frees content from the registration colour

Too much ink on a small shape smears and sets off just like it does on a large one. Seshat 1.8.3 measures ink so that small shapes count too, and only where the product is printed.

What changed

• Small heavy shapes are found. The ink check reports the most ink held over any area of about 1 × 1 mm. A 3 mm arrow at 400 % now counts, while the soft edge of a thin line does not. Before, a heavy area smaller than about 0.1 % of the page could go unseen.
• Only the printed area counts: the bleed box, or the trim with the order's bleed. Printer's marks beyond it never count as heavy ink.
• The registration colour in page content counts in full. It prints on every plate, so a frame or an arrow drawn in it carries 400 %, and more with spot colours. The finding now lists where the ink is too heavy.
• Reduce ink fixes it. Content in the registration colour becomes black on the black plate. Crop marks and other marks beyond the bleed keep printing on every plate, even when they share the same swatch with the content.

Tested on the Ghent PDF Output Suite 5.0 test pages: after reducing to 300 %, every page is at or under the limit, and checking again finds nothing.

Nothing changes in your code. The ink_too_heavy finding now also gives locations.