Here are the basic technologies for photo printing:
The first photo print using inkjet was made in 1989. Until 2005, there were about 5,000 print service providers in the United States and other countries. Epson was the first company to launch an inkjet printer for home purposes.
Canon and HP joined as well and in a few years the dye-based inks were switched to pigment ones. Inkjet still represents the easiest and most preferred way of printing photos as people can quickly get nice photos in the comfort of their own home.
It is the technique used for the most popular alternative print: metal prints. The process consists in a thermal transfer that is performed through dye sub. The image is printed onto a transfer sheet.
Then it's transferred to an aluminum surface with a special coating using heat and pressure. The special heat-sensitive inks provide a highly durable metal photographic print. It is easy to clean and it resists to basically any type of damage.
It refers mostly to toners that are being used to print instant photo books, magazines, calendars or cards. The machines that perform this technology are limited at 12x19 inches.
Chromogenic print (also called "dye coupler prints" or "Digital C-print")
This technology is a bit similar to the old-fashioned photo processing. It refers to the process where a digital frontend is exposed or scanned to paper then it goes into a silver halide backend. There are two options: Digital Minilab and Wide-Format. The original manufacturers of the devices were Kodak, Fuji and Agfa.
Photographers are usually divided into two categories: the ones who regard the output from the chromogenic machines as being the real deal and the ones who think that inkjet is better as it provides an improved permanence and a wider paper selection.
Prints are physical objects that you can display, show off, store, move and enjoy. Though photos exist in the virtual world, they usually get lost between hundreds of folders and they lose their importance. Regardless of the type of print you choose, it's much better than to just store images on your hard drive.
As a matter of fact, all the new techniques such as metal prints are providing incredible opportunities to have durable and crystal-clear images. They can literally last hundreds of years so why shouldn't you dust off those old photos, scan them and convert them into works of art for your grandchildren to see as well? Unlike images on your computer, you can move them to your favorite place of the office or home to make you smile throughout the day.