As SteveRay correctly pointed out, briefly explaining the different methods of reproducing artwork would be a daunting and lengthy task. While some of the basic principles remain basically the same, the methods can range far and wide. I'll touch briefly on a couple techniques, but then I'd like to pose my own question to the forum members who might read this thread.
The level of printing difficulty can range from reproducing a simple, spontaneous charcoal line sketch or pen and ink drawing printed in a single color, to a complex, multi-colored, hand-engraving or wood-cutting process that requires much forethought, exact planning and perfect registration of the colors. A photograph, oil painting or watercolor has to be converted into some type of mechanical process for reproduction, depending on the type of press and printing process that will be used to reproduce the image. The original artwork can be photgraphed or scanned by a computer, and then reassembled into a series of dot or other halftone patterns, set at specific angles for each of the colors. Normally the colors that are used are cyan, magenta, yellow and black - this is called the four-color process, and in most instances will yield pleasing, professional results. Each color in turn has to be perfectly registered, one on top of the other so that those pre-angled screen patterns will re-align into a faithful reproduction of the original. This is the standard for offset printing and is only one small facet of the various reproduction methods.
At times certain colors found in an original will change slightly and subtly when the printer prepares a work for his mechanical process. At times a complex work will call for the addition of more screen-angled plates, in order to print more colors to achieve success at matching the original's color nuances. This is where it starts to get tricky and at times extremely difficult. I've seen fine art collotype reproductions that took over twenty-five different colors to match an original, a very exacting and expensive process, but the end result is exquisite. This is an old, seldom used process simply due to it's complexity, difficulty and cost, like so many other time-consuming crafts and artforms that have fallen by the wayside.
I believe the bookplate that you posted was produced by some kind of engraving process, in which case the artist will grave and cut that image into some sort of metal master plate. The metal can range from hardened steel to a much softer copper for example, but each line has to be hand cut to a proper depth to receive and correctly transfer the ink onto to paper or printing substrate. (plastics and other synthetic materials can also be used as plates) Cutting into the metal can be similar to engraving a rifle or firearm, however, in reverse. The plate is then properly inked, the paper positioned and then must come into contact with the plate under a very precise and uniform pressure to evenly transfer the ink onto the surface of the paper. One small mis-step in any of the pre-press operations can result in abject failure and misery. The engraving, ink, pressure and paper also have to be compatible to achieve a proper result.
Now, it's time for my question to you, simply, what makes art good? Is it the artist, the medium or technique? Perhaps it's the composition, structure and balance? Or is it simply the message that's conveyed to the viewer/interpreter/us? The styles and ingenuity that can be utilized to produce a piece of art are as varied as the subject matter. What is it then that ultimately captures our imaginations when we look at an image? What is it that causes us to think either this is very good, or just more mediocre talent and/or horrible trash? That's what I'd like to hear from you gentlemen, what are your opinions? In the end isn't it all about what the individual viewer sees and interperates for him/her self?
Best regards!
Bill
Ps - a few Belgian anti-German postcards to enjoy ...
