For a photos with a square aspect ratio printed at just bit larger than wallet size, it's hard to beat the Kodak Mini 3 Retro. The printer weighs just shy of a pound, measures 1 by 5 by 4 inches (HWD), and prints 3-by-3-inch photos using dye-sub technology and a four-pass ribbon, with the last pass laying down a clear projective coating. As is typical of dye sub printers, the picture quality is a clear step above what you'd expect from competing printers that use Zink technology. Kodak promises a long life for the prints, too, rating them at up to 100 years. Dedicated snapshot (or small-format) printers are limited to printing at smaller than letter size, and often at only one or two specific sizes. As we point out in our more general roundup of photo printers, these models are less centered on printing from a computer than on printing photos from whatever the source, and most are meant as standalone consumer gadgets. Their focus is on ease of use and on printing snapshots from smartphones.

PORTABLE ALL-IN-ONES. Portable AIOs are even rarer than portable single-function printers. The only one we've seen of late is from HP, with the latest model being the HP OfficeJet 250 Mobile All-in-One. Don't expect a lot from the scanner in the way of paper handling or other scan capability. If you won't need scanning on every trip, consider pairing a printer-only portable with a portable scanner, so you can lighten the load on trips that won't need scanning.Collin is the B2B Hardware Editor for TechRadar Pro. He has been in journalism for years, with experience in small and large markets, including Gearadical, DailyBeast, FutureNet, and more. Resolutions for these printers can be as low as 203 by 200dpi, which is fine for 10- or 12-point text, but can leave smaller fonts and graphics looking a little ragged. However, it's not hard to find models with 300dpi resolution, which is at the lower end of laser quality. And unlike the paper you may remember from fax machines, paper for many thermal printers is available in cut-sheet and fanfold formats, as well as rolls.

Choosing the right category of portable printer for how you print is usually easy. (If you want to print photos from your phone on the go, for example, you'll probably start by looking for a compact photo printer.) But it's still worth knowing what those categories are before you begin shopping. The four main classes of portable printer are (1) all-purpose printers, (2) photo printers, (3) label printers, and (4) monochrome thermal printers.

Brother PocketJet PJ883

At first blush, the thought of a fully portable printer, designed to run on battery power, may seem like a total oxymoron: Carry your Canon? Haul your HP? Truth is, only a few current portable printers can serve as the kind of all-purpose printing tool you might picture when you think of a typical desktop printer. But like most tech today, printers have seen some serious diversification and specialization. Now, you can find a wealth of portable printers that aren't all-purpose but do a single thing well. Most label printers in the paper or office category are meant to sit on a desk. They're small enough to carry easily, but with rare exceptions aren't designed to work on battery power, so not fully portable. On the other hand, printers for plastic, or industrial-type, labeling come in both portable and AC-power only models. Here's what you need to know about them. You'll want to assess the connectivity options. If you want a hassle-free printing experience, use a portable printer that offers wireless connectivity and support for protocols like Apple AirPrint. Most fully portable photo printers today offer wallet-size or slightly larger prints, so if you want a 4-by-6-inch picture size, which the Canon Selphy CP1500 offers, you have limited choices. Fortunately that doesn't mean you have to make compromises. The latest in the long-running Selphy line of portables, the CP1500 in particular delivers a solid feature set; drugstore-grade photo quality, courtesy of its dye sub technology; and a reasonably low running cost, at a bit above or below 30 cents per 4-by-6-inch photo. (The cost covers both the paper and required dye rolls.) Canon has done well to shrink this full-color inkjet printer to a size that will fit easily into a briefcase without compromising print quality. It comes with key features such as Wi-Fi and Wi-Fi Direct connectivity, an OLED screen, and the ability to store custom templates. These could be useful for repeat printing, whatever forms your business uses regularly.