When an artist decides to sell prints of their work they will work carefully with a print professional. For Gallery quality work the relationship between the artist and the printer is often a close one developed over many years.
The printer will scan the original and then work with the artist to agree a final image for printing, this can involve manipulating the image to ensure it is best for printing so can go through many versions.
The final agreed version is called the artist's proof and is the second most valuable type of art you can purchase, second only to the original.
Each individual artist will have their own policy as to how many proofs they make available and when, but it is always a very small number (often only one) and normally only released to the market towards the end of the print edition.
At CreARTives we see artists proofs as special and will only release them towards the end of the run and whilst some may be offered for general sale they also may be made available only to members or established collectors.