(1) A Means of Fanzine Reproduction

A means of fanzine reproduction, spirit duplication (the best-known U.S. brand name was ditto), is known for the smudgy purple copies generations of schoolchildren received as handouts, but being cheap and easy, with machines widely available secondhand (or by younger fans at school), it was also very popular with faneds, especially for short-run zines like apazines.

See the Fancy 1 explanation below for the process.

Some people incorrectly confuse a spirit duplicator with a mimeograph, but that uses ink-based process.

from Fancyclopedia 2 ca. 1959
A method of reproducing by dye-transfer process; like hektoing (and hekto carbons are used to make the master) but using a dye solvent instead of a gelatin transfer medium. Moistened sheets are pressed against the master, and take up enough of the pigment to make a good copy. The ditto machine costs more than mimeos of comparable quality, but cost per page of reproduction is less. Besides the reproduction-range up to 300 copies because no ink is wasted, there is the further advantage that some copies may be run off now and others next week. Ditto is usually in purple (colors are available, as below) and on smooth surfaced paper; this is a specimen of it. Oh, and Laney called Walter A Coslet's spiritduplicating plant a Dittorium, tho Coslet's ditto is actually a Wolber machine.

from Fancyclopedia 2 Supplement ca. 1960:
This is a trademark name, to which the company owing it is ferociously attached. They didn't sue, fortunately.
from Fancyclopedia 1 ca. 1944
The Ditto company's direct process is related to hektoing, but stands somewhat beyond it. Hekto carbons are used, laid face up under the master sheet, so that drawing or typing on one side of the master gives mirror writing on the other side in hekto pigment. The master sheet is put face outward around a revolving drum similar to a mimeo's, and as each copy sheet goes in, it is slitely moistened with something, and takes off just enuf of the pigment on the master to make a good copy. Besides the reproduction-range up to 300 copies because no ink is wasted, there is the further advantage that some copies may run off now and others next week.

(2) A Convention

A small, friendly, fanzine-fan convention held in the fall, ditto is named for the best-known brand of spirit duplicator.

Thus, maintains Dick Smith, who once worked in a building that had housed that company, when not beginning a sentence, the name of the con ought to be spelled in lowercase, matching the duplicator's expired trademark.

Ditto moves around to different locations as chosen by the Ditto Masters.

Ditto conventions up to 2005, and 2007 have been:

Con Date & Location Organized by Notes
Ditto 1 1988 Toronto Bob Webber, Taral, Mike Glicksohn, Alan Rosenthal, Catherine Crockett, et al.
Ditto 2 1989 San Francisco Patty Peters & Gary Mattingly
Ditto 3 1990 Chicago Dick & Leah Zeldes Smith
Ditto 4 October 18-20, 1991 Virginia Beach Cathy Doyle & Kip Williams
Ditto V October 23-24, 1992 Cincinnati Bill Bowers, Pat & Roger Sims and the Cincinnati Fantasy Group in conjunction with Octocon 29
Ditto 6 1993 Cambridge, MA Bob Webber & Sarah Prince
Ditto 7 1994 Ann Arbor Leslie Smith & Ken Josenhans
Ditto 8 November 3-5, 1995 Seattle Alan Rosenthal & Janice Murray
Ditto 9 1996 El Paso Richard Brandt & Michelle Lyons
Ditto 10 Oct 24-26, 1997 Cincinnati Pat & Roger Sims, Bill Bowers, and Bill Cavin and the Cincinnati Fantasy Group in conjunction with Octocon 34
Ditto 11 1998 Nov 6-8, Newport, RI Priscilla Olson, Mark Olson, Bob Webber and George Flynn
Ditto 12 1999 Minneapolis Karen Cooper and Minn-Stf in conjuction with Fallcon
Ditto 13 2000 Dallas Cris & Neil Kaden
Ditto 14 Oct 12-14, 2001 Bloomington, IL Dick & Leah Zeldes Smith, Bob & Fern Tucker, Henry & Letha Welch Held jointly with FanHistoriCon 11
Ditto 15 2002 Toronto Murray Moore, Colin Hinz, Catherine Crockett & friends
Ditto 16 Oct. 10 - 13, 2003 Eugene, Oregon Alan Rosenthal, Loren MacGregor and Janice Murray
Ditto 17 October 8-10, 2004 Orlando, Florida Pat & Roger Sims
Ditto 18 October 14-16, 2005 Milwaukee, Wisconsin Henry & Letha Welch, Trinlay Khadro, Henry Osier, Greg Rihn, Georgie Schnobrich and Dick & Leah Zeldes Smith
Ditto 19 2007 Mendocino County California Alan Rosenthal AKA ArtCon

Art Widner reports:

I was totally gobsmakt, gabberflasted & flatterd all to hell that 30 people came from all over the world to the most hard to get to (Panama City was easy) wild Mendocino Coast to help me celebrate. & they brot 15 bottles of single malt in the bargain. I didnt count, but somebody told me. In spite of my warning "No presents but yr presence" some of the bottles were presents. Thanx to Ian Sorenson & Yvonne Rowse from Scotland; I hope the chilly summer fog made them feel at home. & the 3 from Toronto, 2 from Detroit, & the usual suspex from Seatl & the Barea. Not to mention all my cool gchiln; Missy all the way from France, & the Tuckerized baby offn Mt. Baker….. Ive had sevral xcuses from various fen since, wch may b flattery, but i acept that they really wantd to b there but cdnt. Alan Rosenthal did a great job organizing it & i hav no complaints.