You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "how many colors of ink are used to print?" whose answer is four.
Each document should contain about 30 words, and these documents should contain useful information.

Query: common number of ink colors used in printing
Useful Output:

Doc 1: The "four-color" in "four-color printing" refers to the four ink colors—cyan, magenta, yellow, and black (CMYK)—used in offset printing presses
Doc 2: In this method, a combination of just four inks, cyan, magenta, yellow and black, can generate a large gamut of colors. Those colors are not
Doc 3: Four-color process digital printing utilizes traditional CMYK inks to produce most full-color print jobs. The four colors – cyan, magenta,
Doc 4: Using Cyan, Magenta, Yellow, and Black, the CMYK printing process uses ink dots to create a final print that accurately matches your design. No
Doc 5: In CMYK, four ink colors are combined to create a final color. Cyan (C), magenta (M), yellow (Y), and black (K) are each housed in their own cartridge.