The Linux kernel will let you speak with any printer that you can plug into a serial, parallel, or usb port, plus any printer on the network. Unfortunately, this alone is insufficient; you must also be able to generate data that the printer will understand. Primary among the incompatible printers are those referred to as "Windows" or "GDI" printers. They are called this because all or part of the printer control language and the design details of the printing mechanism are not documented. Typically the vendor will provide a Windows driver and happily sell only to Windows users; this is why they are called Winprinters. In some cases the vendor also provides drivers for NT, OS/2, or other operating systems.
Many of these printers do not work with free software. A few of them do, and some of them only work a little bit (usually because someone has reverse engineered the details needed to write a driver). See the printer support list below for details on specific printers.
A few printers are in-between. Some of NEC's models, for example, implement a simple form of the standard printer language PCL that allows PCL-speaking software to print at up to 300dpi, but only NEC knows how to get the full 600dpi out of these printers.
Note that if you already have one of these Winprinters, there are roundabout ways to print to one, but they're rather awkward. SeeSection 12 in this document for more discussion of Windows-only printers.
As for what printers do work with free software, the best choice is to buy a printer with native PostScript support in firmware. Nearly all Un*x software that produces printable output produces it in PostScript, so obviously it'd be nice to get a printer that supports PostScript directly. Unfortunately, PostScript support is scarce outside the laser printer domain, and is sometimes a costly add-on.
Un*x software, and the publishing industry in general, have standardized upon Postscript as the printer control language of choice. This happened for several reasons:
Postscript arrived as part of the Apple Laserwriter, a perfect companion to the Macintosh, the system largely responsible for the desktop publishing revolution of the 80s.
Postscript programs can be run to generate output on a pixel screen, a vector screen, a fax machine, or almost any sort of printer mechanism, without the original program needing to be changed. Postscript output will look the same on any Postscript device, at least within the limits of the device's capabilities. Before the creation of PDF, people exchanged complex documents online as Postscript files. The only reason this standard didn't "stick" was because Windows machines didn't usually include a Postscript previewer, so Adobe specified hyperlinks and compression for Postscript, called the result PDF, distributed previewers for it, and invented a market for their "distiller" tools (the functionality of which is also provided by ghostscript's ps2pdf and pdf2ps programs).
Postscript is a complete programming language; you can write software to do most anything in it. This is mostly useful for defining subroutines at the start of your program to reproduce complex things over and over throughout your document, like a logo or a big "DRAFT" in the background. But there's no reason you couldn't compute π in a Postscript program.
Postscript is fully specified in a publically available series of books (which you can find at any good bookstore) and also online at http://partners.adobe.com/asn/developer/technotes/postscript.html. Although Adobe invented it and provides the dominant commercial implementation, other vendors like Aladdin produce independently coded implementations as well.
Failing the (larger) budget necessary to buy a Postscript printer, you can use any printer supported by Ghostscript, the free Postscript interpreter used in lieu of actual printer Postscript support. Note that most GNU/Linux distributions can only ship a somewhat outdated version of Ghostscript due to the license. Fortunately, there is usually a prepackaged up to date Ghostscript made available in each distribution's contrib area.
Adobe now has a new printer language called "PrintGear". I think it's a greatly simplified binary format language with some Postscript heritage but no Postscript compatibility. And I haven't heard of Ghostscript supporting it. But some PrintGear printers seem to support another language like PCL, and these printers will work with GNU/Linux (if the PCL is implemented in the printer and not in a Windows driver).
Similarly, Adobe offers a host-based Postscript implementation called PressReady. This works much like Ghostscript does to provide Postscript support for a non-Postscript printer, but has the disadvantage that it runs only on Windows.
You can look in several places to see if a particular printer will work. The cooperatively maintained Printing HOWTO printer database aims to be a comprehensive listing of the state of GNU/Linux printer support. A summary of it is below; be sure to check online for more details and information on what driver(s) to use.
The best bet for new printer shoppers is to consult the list of suggested printers. These center around color inkjets and mono laser devices. You can even help support this document and the website by buying from one of affiliated vendors.
Ghostscript's printer compatibility page has a list of some working printers, as well as links to other pages.
Google groups contains hundreds of "it works" and "it doesn't work" testimonials. Try all three, and when you're done, check that your printer is present and correct in the database, so that it will be listed properly in this document in the future.
This section is a summary of the online database. The online version includes device specifications, notes, driver information, user-maintained documentation, manufacturer web pages, and interface scripts for using drivers with several print spooling systems (including LPR, LPRng, PDQ, and CUPS). The online version of this list is also interactive; people can and do add printers all the time, so be sure to check it as well. Finally, if your printer isn't listed, add it!
Note that this listing is not gospel; people sometimes add incorrect information, which are eventually weeded out. Entries which have not been sanity-checked are marked with an asterisk (*). Verify from Google Groups that a printer works for someone before buying it based on this list.
Printers here are categorized into four types:
Perfect printers work perfectly - you can print to the full ability of the printer, including color, full resolution, etc. In a few cases printers with undocumented "resolution enhancement" modes that don't work are listed as perfect; generally the difference in print quality is small enough that it isn't worth worrying about.
You can print fine, but there may be minor limitations of one sort or another in either printing or other features.
You can print, but maybe not in color, or only at a poor resolution. See the online listing for information on the limitation.
You can't print a darned thing; typically this will be due to lack of a driver and/or documentation on how to write one. Paperweights occasionally get "promoted", either when someone discovers that an existing driver works, or when someone creates a new driver, but you shouldn't count on this happening.
And without further ado, here is the printer compatibility list:
Table 1. Linux Printer Support
Color StyleWriter 1500
Personal Label Printer+*
Personal Label Printer
Artisan 1023 penplotter*
9-pin 136 Col*
9-pin 136 Col*
Color LaserJet 5
C LaserJet 4500*
DDP 70 (with MicroPress)*
4029 030 LaserPrinter 10*
CP50 Color Printer*
2425 Turbo EX*
Aficio Color 2206*
LC 24-15 Multi-Font*
3693d color printer, 8-bit mode*
It's a bit difficult to select a printer these days; there are many models to choose from. Here are some shopping tips:
You get what you pay for. Most printers under $200-300 can print reasonably well, but printing costs a lot per page. For some printers, it only takes one or two cartridges to add up to the cost of a new printer! This is specially true for cheap inkjets. Similarly, the cheapest printers won't last very long. The least expensive printers, for example, have a MTBF of about three months; obviously these are poorly suited for heavy use.
Inkjet printheads will clog irreparably over time, so the ability to replace the head somehow is a feature. Inkjet printheads are expensive, with integrated head/ink cartridges costing ten times (!) what ink-only cartridges go for, so the ability to replace the head only when needed is a feature. Epson Styluses tend to have fixed heads, and HP DeskJets tend to have heads integrated into the cartridges. Canons have three-part cartridges with independently replaceable ink tanks; I like this design. OTOH, the HP cartridges aren't enormously more expensive, and HP makes a better overall line; Canon is often the third choice from the print quality standpoint. Epson Styluses and HP inkjets are the best supported by free software at the moment.
Laser printers consume a drum and toner, plus a little toner wiping bar. The cheapest designs include toner and drum together in a big cartridge; these designs cost the most to run. The best designs for large volume take plain toner powder or at least separate toner cartridges and drums.
The best color photograph output is from continuous tone printers which use a silver halide plus lasers approach to produce—surprise!—actual photographs. Since these printers cost tens of thousands to buy, Ofoto.com offers inexpensive print-by-print jobs. The results are stunning; even the best inkjets don't compare.
The best affordable photo prints come from the dye-sublimation devices like some members of the Alps series (thermal transfer of dry ink or dye sublimation), or the few consumer-grade Sony photo printers. Unfortunately the Alps devices have poor free software support (the one report I have from a Alps user of the Ghostscript driver speaks of banding and grainy pictures), and even then it's unclear if the dye-sub option is supported. I have no idea if the Sonys work at all.
The more common photo-specialized inkjets usually feature 6 color CMYKcm printing or even a 7 color CMYKcmy process. All photo-specialized printers are expensive to run; either you always run out of blue and have to replace the whole cartridge, or the individual color refills for your high-end photo printer cost an arm and a leg. Special papers cost a bundle, too; you can expect top-quality photo inkjet output to run over a US dollar per page. See also the section on printing photographs later in this document, and the sections on color tuning (such as it is) in Ghostscript.
Lately color lasers have been getting a lot cheaper, these devices may be interesting for color reports. Color lasers are a lot cheaper per page than inkjets. However they may still not be suited for photographs. One day color lasers may become common and replace those boring monochrome laser printers.
Speed is proportional to processing power, bandwidth, and generally printer cost. The fastest printers will be networked Postscript printers with powerful internal processors. Consumer-grade printers will depend partly on Ghostscript's rendering speed, which you can affect by having a reasonably well-powered machine; full pages of color, in particular, can consume large amounts of host memory. As long as you actuallyhave that memory, things should work out fine.
If you want to print on multicopy forms, then you need an impact printer; many companies still make dot matrix printers, most of which emulate traditional Epson models and thus work fine.
There are two supported lines of label printer; look for the Dymo-Costar and the Seiko SLP models. Other models may or may not work. Avery also makes various sizes of stick-on labels in 8.5x11 format that you can run through a regular printer.
Big drafting formats are usually supported these days by monster inkjets; HP is a popular choice. Mid-sized (11x17) inkjets are also commonly used for smaller prints. Much plotting of this sort is done with the languages RTL, HP-GL, and HP-GL/2, all of which are simple HP proprietary vector languages usually generated directly by application software.