Optimal scanning rez for B&W photos?

[AFairley]

What is people's take on this?  I'd like to keep as much detail and tonality of the print (negs are long lost) as possible for potential reprinting, but don't want to waste space scanning "empty detail."  Most of the prints are 5x7 or 8x10, a variety of 35mm and 4x5, mostly on air dried F surface paper; if I reprinted it most likely would be at their original size, certainly never more that 2x the size of the prints I have.  My inclination is to scan at 360 dpi since I can feed that straight into the 3880 to get a print at the original size, but am curious to hear others' opinions.  I'm using a V700 for the scanning, BTW.

[Bart_van_der_Wolf]

What is people's take on this?  I'd like to keep as much detail and tonality of the print (negs are long lost) as possible for potential reprinting, but don't want to waste space scanning "empty detail."

Hi Alan,

By scanning with too low a resolution, you will create more grainy scans. It's due to grain-aliasing.

I'd scan at maximum (native) resolution for the scanner, and then down-sample until you lose detail that matters. When you print large, you'll probably don't down-sample at all because there is still some benefit to native scan resolution and down-sampling can cause issues if not done properly.

Cheers,
Bart

[AFairley]

Thanks, Bart I had not thought of the aliasing aspect.  However, when you speak of the "native" resolution of the scanner, is that the published spec or the actual achievable?  For instance, the V700 has a published optical resolution of 4800 dpi, but various reviews show the actual achievable resolution (which I expect results from taking the scanner lens into account) is around 2300 dpi, or about half.

[Christoph C. Feldhaim]

Its very simple.
Scan as high res as possible, downscale later when needed.
Bart named it: grain aliasing.

[AFairley]

Surely grain aliasing is not a factor when scanning prints? 

[Bart_van_der_Wolf]

Surely grain aliasing is not a factor when scanning prints?

Hi Alan,

If grain is not visible in the printed output, then not. But there may be paper structure that will be 'enhanced'. Also, you'd probably need at least 600 PPI to resolve the detail in a C-print or process-print, even more in a contact print from a negative. An inkjet print would require 2400PPI.

Cheers,
Bart