The rule of thumb for how closely reproductions
should be valued against the original is at least a 10:1
arbitrage on the price. If it's less than this, it stops
making sense. Imagine a reproduction selling for $1000 and
the original selling for $4000; you would find most people
stretching to buy the $4000 original, not really a big
incentive to have reproductions produced.
If there's a painting you're thinking of buying, ask the
gallery for the final sales value of the original piece.
Assuming there is at least a 10:1 value difference between it
and the reproduction you want, feel free to do your research
and establish the values of the artist. This is the most
assured path to validating the price value of your purchase.
You will find unembellished reproductions sell for as little as
$1,000 and the original counterpart valued at around
$40,000. This kind of arbitrage creates an incentive to buy
the reproductions and goes a long way towards increasing
their value over time.
Consider when looking at your favorite piece in a
gallery if the artist has other pieces in the gallery or in their
studio you may want to look at. This can be valuable in
assuring yourself the work you're now considering is actually
the work you love the best from those available by the artist.
Inquiring about this can often lead you on an interesting