Printing is not one thing
Printing is not only printing leaflets, business cards or large banners - it also prints other, necessary materials such as: stickers, self-adhesive letters or labels. In principle, everything that comes out of the printing house can be included in the category of printing.
There are plants specializing in the production of only a specific group of printed materials: eg leaflets, or only large-format printing. However, this results from a simple thing: for every type of printing you need to have the right machine, and these take up space and cost a lot. That is why printing plants limit the amount of services provided.
Water and waterless - offset printing
Offset printing is the most popular type of printing in today's printing industry. It is true that it has many varieties and uses different techniques and materials (paint, paper). The main division is cold printing, where the paint is fixed by soaking into paper. While the 'hot' offset where the printed paper web passes through the drying tunnel.
The classic offset (water) is associated with the use of water rollers and hydrophilic and hydrophobic surfaces, however, this method is already abandoned due to the difficulty in obtaining a good balance of water and oil paint.
The successor of this method is anhydrous offset printing where silicone molds are used instead of water.
DTP work programs
There are more and more graphics processing programs, from the most popular Photoshop to less known and free ones like Inkscape. Professionals usually use one or two proven programs, which translates into their high productivity.
In the work of graphics or DTP operator you usually need a program for processing vector and raster graphics. You can also include word processors, programs provided by print equipment manufacturers, to the pool of programs needed for such work.