Links. Lecturas sobre fotografía. Sotheby's. Investing in Art Photography: What to Keep in Mind
Sotheby's ( y Christie's también) publican artículos sobre arte , todo tipo de arte, que tienen habitualmente bastante interés.
Por ejemplo
Investing in Art Photography: What to Keep in Mind
destacar
Size of the edition
An artwork is precious because it’s unique. A photographic print is a
 copy and, provided the original negative or digital file still exists, 
lots more copies can be made in future. This partly explains why the art
 world has in the past been wary of photography. Editioning gets around 
this by setting a limit how many prints will ever be produced of a 
particular photograph. Editions are designed to cultivate rarity so, as a
 rule, avoid big ones. With two hundred versions of your print out there
 in the world, you’re unlikely to see its worth increase astronomically.
 The number of the print’s place in the edition — from 1/10 to 10/10, 
say — will normally be included on it, along with the artist’s 
signature. Further up the edition, fewer prints are available, which can
 push up the price.
- Como complemento destacar el alto precio obtenido en su reciente subasta de fotografías por:
 
YVES KLEIN (1928-1962) / HARRY SHUNK (1924-2006) & JÁNOS KENDER (1937-2009)
        
LEAP INTO THE VOID (5, RUE 
GENTIL-BERNARD, FONTENAY-AUX-ROSES, OCTOBER 1960) (ARTISTIC ACTION BY 
YVES KLEIN - COLLABORATION HARRY SHUNK AND JÁNOS KENDER)