Comic book halftone: Ben Day dots and how to make them

The dots that people call comic book halftone are two different things. One is a flat tint: a field of dots that are all the same size, used to fill an area with an even lighter shade of an ink. In the printing trade this was called Ben Day, after its inventor. The other is a true halftone, where the dots change size to follow a tone, as in a fade or a shadow. They are made in different ways. What is a halftone? covers the second kind in full.

Flat tint
Every dot the same: an even 25%

Halftone
Dot size follows a tone

Ben Day tints

Benjamin Day of West Hoboken, New Jersey, patented his “Improvement in Printing-Films” on 22 April 1879 (US patent 214,493). The film was a thin, nearly transparent sheet of gelatine on a silk backing, cast from an engraved block so that its face carried a raised texture of fine lines. The artist inked the film, laid it face down over the drawing, and rubbed the back with a stylus wherever shading was wanted. Because the film was transparent, the outline of the picture showed through as a guide.

Day’s claim for it was speed. Good cross-lining or hatching done by hand was, he wrote, “one of the most difficult, laborious, and expensive operations known to the artist”, and with his films an artist could do in an hour what would otherwise take a month “if executed in the usual manner”. The patent also covers films cast with a “different character of lines, grain, or stipple”, and describes laying a flat tint through a paper stencil. It never uses the word dots: stipple and grain are its nearest terms.

By 1913 the name was a trade term. Stephen Horgan’s manual of photoengraving defines Ben Day in its glossary as a “method of laying tints named after the inventor”, and laying down tints as “covering surfaces with lines, dots or a grain” (Horgan’s Half-tone and Photomechanical Processes).

The point of a tint is that it gives a printer more shades than there are inks. A press prints each ink at full strength or not at all. Cover a quarter of an area with small red dots and it reads as pink. Lay a light tint of blue over a tint of yellow and it reads as green.

How a tint differs from a halftone

	Flat tint (Ben Day)	Halftone
Dot size	The same across the area	Changes from dot to dot
What it shows	One even shade	A picture or a fade
Made from	A pattern laid into an outlined area	A photograph or a gradient

A halftone keeps its dots in rows and changes their size, as a newspaper photograph does. A tint is the simplest case of the same idea: a halftone of an area that is one tone all over.

The dots as art

This page uses comic halftone for that look: dots large enough to be seen as dots.

How big to make the dots

A tint is described by two numbers: the spacing of the dots and how much of the area they cover. For round dots on a square grid, the radius is the spacing times the square root of the coverage divided by π.

Coverage	Radius, as a share of the spacing	Dot width at 2 mm spacing
10%	0.18	0.7 mm
25%	0.28	1.1 mm
50%	0.40	1.6 mm

Round dots touch at 78.5% coverage, so tints for shading sit well below that.

For the angle, 45° is the classic choice. Horgan explained why halftone dots were always set that way: “it was found at that angle they were least objectionable. Were they arranged, for instance, horizontally and vertically, they would be most obvious”. Dots in straight rows and columns look more like a grid than a shade.

For the look, the dots have to be visible at the size the work will be seen, so judge the spacing at the final size and not zoomed in.

Making flat tints

As a seamless pattern. The SVG pattern generator opens on a dot pattern. Choose the scale and weight, and download an SVG that repeats without a seam. It puts one dot in the middle of each square tile, so the rows run straight, not at 45°. At medium weight the dot is 40% of the tile wide and covers 12.6% of the area. The result is a pattern fill, right for screens and print but not for cutting machines.

As real outlines. The free halftone set has two flat tints on a 45° grid, an even 30 percent and an even 60 percent, in SVG and transparent PNG. In the SVG each dot is a closed outline drawn from a circle and no two touch, so the tint can be cut as a stencil or screen printed as one ink.

Making halftone shading

For a fade or a shadow, the dots have to follow a tone, and that means screening a gradient or a picture.

• A fade: see halftone gradient.
• GIMP 2.10: Filters > Distorts > Newsprint, with the colour model set to Black on White and the pattern to Circle. The period sets the spacing in pixels (GIMP manual).
• Krita: the Halftone filter. Its manual says that in Intensity mode “the resulting effect is like the one used in black and white newspaper images”, and that Independent Channels gives “an effect similar to the one in colored magazine images” (Krita manual).
• Affinity Photo 2: the Halftone filter, from the Layer menu under New Live Filter Layer, with a Monochrome screen and a cell size (Affinity help).

Ready-made pieces save the work for the common shapes: a radial fade for behind a figure, a corner fade for a panel, a burst for an impact, and a band for a border.

For a whole photo in dots, Plotcaster’s Dither style with a Bayer pattern gives equal dots on a regular grid, closer to a tint than to a halftone. It saves as an SVG of small pen-drawn loops or as a 1-bit PNG. To make size-changing dots as shapes of your own, see vector halftone.

Dots in more than one colour

Tints of two inks can be laid over each other, and two dot grids on top of each other can interfere. Horgan’s glossary has the word for it: pattern, the “name given to the moire effect when screens or tints are superimposed on one another”.

Two ways round it:

• Turn the second grid. The printing standards keep the screens of cyan, magenta and black 30° apart: CMYK halftone has the rule and a figure. For two colours, 45° apart is the widest a square grid allows, because the grid looks the same after a quarter turn.
• Keep the same angle and spacing and shift the second grid by half a step, so that its dots fall in the gaps of the first. On a screen the two layers stay lined up. In print they may not: Horgan warns that impressions from the same screen are “most likely” to be out of register, and that moiré follows.

Questions

Are Ben Day dots and halftone dots the same thing? No. Ben Day dots are one size within an area and make a flat tint. Halftone dots change size to draw a picture. Both are patterns of small dots of solid ink.

Did Ben Day films only make dots? No. The 1879 patent is mostly about lines: straight, swelled, waved and cross-hatched. It mentions grain and stipple as other faces a film could have.

Which is right for my artwork? Use a flat tint where an area should be one lighter shade, and a halftone where it should fade or follow a photograph.