Here are two tell tale signs that your art is a reproduction:
1. If you painting or print has the name of a museum written on the front or back, you are looking at a piece which was reproduced as part of the museum’s marketing strategy for a particular exhibition or reproduced as an example from their permanent collection. Sometimes these pieces are trickier than others. Sometimes the art is reproduced on canvas and framed; sometimes the “painting” will have a white border around it stating the date of the exhibition and the name of the museum. Even if this exhibition is deemed “old”, for example it was in the 1970s or 1980s, this does not mean that your print has great value. It is a still a mass produced print. The exception to this (and there are always exceptions), would be if you have one of these prints that was signed by the artist. I remember that Marc Chagall was present at least one of his later exhibitions in the 1980s, and actually signed mass produced posters. If you think your piece does have an original signature, look to point #2 below and examine it for the same pattern.
2. If you look closely at your art under a magnifying glass and see a tiny dot pattern which forms the image, sometimes seen as a moiré of dots, you have a four color offset print, a reproduction. Some of these images are printed on paper; others created on canvas. Some will have computer generated, three-dimensional brush strokes to make you think you have an original. Some of these images feature real, random flourishes of paint, brushed on top of the reproduction, also to make you think you have an original work.
The key to understanding your art is observation. It might take some time to recognize reproductions, but once you do, you can never go back. We’re always here to assist you when you have questions.