An architectural print is a two-dimensional stylized drawing of what the architect wants to accomplish with his structure. A detail print focuses on a smaller scope in the building, like an archway, with specific measurements, or a crown molding along the wall. An artist, or the architect, makes a very intricate drawing of a detail in the building and can add color, dramatic shadowing or another art techniques to turn the drawing from a sketch with dimensions and numbers to a work of art to hang on a wall.
A blueprint is what an architect would show the builder or owner of a new building he is constructing. The blueprint would include the building's dimensions, along with a basic outline of everything involved, but the detail prints are much more in-depth in showing what the end result will look like, instead of a drawing to scale which includes measurements.
Some prints are extremely beautiful. Sometimes an owner will keep an original sketch of the building before it became a reality. New homeowners who are designing their homes will sometimes keep a detail piece, especially if they had a say in the end result. In Ayn Rand's book "The Fountainhead," main character Howard Roark is an architect who creates very beautiful designs and many of his sketches end up as framed pictures among his friends.
In the early Roman times, architecture focused on detail and beauty. Every column was chiseled and statues were added to all major buildings. This trend continued for many centuries into the Renaissance. It wasn't until the Industrial Revolution that architecture began to look predominately boxy. The Industrial age brought steel and the ability to make a skyscraper, which until the 19th century was impossible to do. Buildings began to lose many of the one-of-a kind detail that made original architectural prints so sought after. Modernism has brought back some of the detail work, but much architecture is based on measurements and details that have been done before and have few original touches.