Collotype vs Halftone
コロタイプ / ハーフトーン（網点）
Collotype comes from Planographic Printing and Halftone from Print Expression. They are reached for with some of the same intent, which is where they get confused.
Collotype
A photomechanical process that prints ink from a photographically prepared gelatin surface. Fine, irregular reticulation carries detail and smooth-looking tones rather than a regular halftone screen. It has reproduced photographs and artworks; it is unrelated to the collaged matrix of a collagraph.
Halftone
Halftone converts continuous tone into regularly spaced dots of changing size so it can be printed; from a distance they return to tone, while enlargement reveals the screen as material.
| Collotype | Halftone | |
|---|---|---|
| Era | 19th century–present | 1880s– |
| Family | Planographic Printing | Print Expression |
| Kind | Technique | Technique |
| Cues | Detailed images derived from photographs or originals / Apparently continuous tonal changes / Fine irregular reticulation under magnification / Tone without a regular dot screen | Large and small dots on one fixed pitch / Light and shade made by dot area / Rosettes from differently angled color screens / An image that changes between normal and magnified viewing |
| Best used for | Exhibitions and teaching that compare Collotype with neighbouring print techniques · Publications studying lines, tones and paper through documented works | Printing photographs in newspapers, magazines and packaging with limited inks · Using enlarged dots to make reproduction and print itself the subject |
| Type | Keep lettering in the work separate from added labels; place medium, artist and date outside the image. | Choose bold type or simple contours that survive conversion into dots. |
| Composition | Pair details with the whole image and distinguish the microscopic pattern from overall tone. | Place normal-scale image and enlarged screen together to exploit changes in viewing distance. |
| Material | Check the collection medium record and the paper and ink; do not infer materials from screen colour alone. | Set line frequency, dot shape, screen angle and ink color, then translate tone into dot area. |
| Caution | A screen image may conceal the diagnostic pattern. Use the collection's medium record, and distinguish collotype from collagraph. | Polka dots are not halftone. Dot size must carry continuous tone in relation to printing resolution. |