We will tell you straight — even when it is not what you hoped. It is free either way, and now all three are welcome anyway.
We take prints and posters now, so a print is no longer a rejection — it is simply a different label and a different price. What still matters is that it goes on the site as what it actually is. That is the whole basis on which a stranger buys from another stranger.
Get your phone as near as it will focus and take a picture of the paint surface. Enlarge it. A regular pattern of dots or rosettes is a printing press. Paint never does that. It is the single most reliable test there is, and it is why that photograph is the one we ask for.
Hold a torch flat against the surface, almost parallel to it. Real brushwork throws shadows that follow the image — thick where the artist loaded the brush. Fake texture on a canvas transfer runs uniformly across sky and tree alike, because it was rolled on afterwards.
An old painting has an aged stretcher, tacking margins, keys in the corners, and often a framer's label. A modern reproduction has clean MDF, a barcode, or a stapled print wrapped round.
If the signature carries the same dot pattern as the rest of the surface, it was printed with the image.
For a poster this is the question that decides the value. An original printing from the year of the exhibition or the film's release is worth a great deal more than a reissue printed later. Look for a printer's credit in the margin, fold lines from the way they were originally shipped, paper that has aged evenly, and a size that matches the standard of its era.
If you are not sure, say so. "Not sure" is a perfectly good answer and it protects you completely.
List the artwork