usefulness of 7200 dpi for black and white film scanning

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alexterkinov

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I scanned some black and white films with HP Scanjet 4600. The pointed resolution was 2400 dpi or Less . See samples. I want to make rescan with Primefilm 3650u or 7250u. There is essential price difference. So please write if there are any essential advantage in quality when scanning with 7250u for scanning of black and white films of bad quality.
 
Are you going to print them in some enormous sizes? If not, I really don't see the point of scanning at such a high resolution
 
If we're talking a 4k TV, that's 3840x2160. On a 32" TV (assuming 30x15 screen size?) that's 128ppi (3840/30) so anything higher than that, your TV isn't going to be able to resolve anyway. An 8k telly is 7680x4320 so assuming the same screen size that's (7680/30) 256 ppi)

To calculate yourself, get the resolution of your telly, get the size of the screen and divide the latter into the former. This will give you the ppi (pixels per inch) that the screen will display. 2400ppi is massive overkill for any online (including TV) medium. As Mads says, you only really need super resolution if you're going to print big and get your nose up close.

(It's early so if my logic is flawed, I apologise!)
 
Thank you for popular explanation of principle. But you have written about resolution of ready image on TV. Should I take the size of the films (1,4 inche) and divide tv resolution on film size?
Harlequin565 said:
If we're talking a 4k TV, that's 3840x2160. On a 32" TV (assuming 30x15 screen size?) that's 128ppi (3840/30) so anything higher than that, your TV isn't going to be able to resolve anyway. An 8k telly is 7680x4320 so assuming the same screen size that's (7680/30) 256 ppi)

To calculate yourself, get the resolution of your telly, get the size of the screen and divide the latter into the former. This will give you the ppi (pixels per inch) that the screen will display. 2400ppi is massive overkill for any online (including TV) medium. As Mads says, you only really need super resolution if you're going to print big and get your nose up close.

(It's early so if my logic is flawed, I apologise!)
Click to expand...
 
Harlequin565 said:
If we're talking a 4k TV, that's 3840x2160. On a 32" TV (assuming 30x15 screen size?) that's 128ppi (3840/30) so anything higher than that, your TV isn't going to be able to resolve anyway. An 8k telly is 7680x4320 so assuming the same screen size that's (7680/30) 256 ppi)

To calculate yourself, get the resolution of your telly, get the size of the screen and divide the latter into the former. This will give you the ppi (pixels per inch) that the screen will display. 2400ppi is massive overkill for any online (including TV) medium. As Mads says, you only really need super resolution if you're going to print big and get your nose up close.

(It's early so if my logic is flawed, I apologise!)
Click to expand...
Not sure Ian, I think maybe it was a bit early... the pixels per inch for the TV and the film frame scan aren't really the issue. For the 4K TV, you want 3840 pixels on the longer dimension, which on the film frame is 1.5 inches, so a scan at 2560 samples per inch would give you all the pixels you'd need, on both dimensions. In practice, 2400 spi would be fine, given TV viewing distance.
 
alexterkinov said:
I scanned some black and white films with HP Scanjet 4600. The pointed resolution was 2400 dpi or Less . See samples. I want to make rescan with Primefilm 3650u or 7250u. There is essential price difference. So please write if there are any essential advantage in quality when scanning with 7250u for scanning of black and white films of bad quality.
Click to expand...
The Primefilm 3650u is known here as the Reflecta Crystalscan 3600. It's quite old, originally released in 2003. Only obsolete versions of Silverfast support it (6.6, which won't run under modern MacOS, though I don't know about Win10). I understand that Vuescan Pro does support it.

It looks like the Primefilm 7250u might also be a re-badged Reflecta Crystalscan 7200, released in 2005.

It's worth remembering that the headline resolution figures are always well over what can be achieved in practice. Filmscanner.info gives the actual, tested scan resolution of the Crystalscan 7200 as about 3300 samples per inch. The early paragraphs of that review suggest the Crystalscan 3600 had similar resolution. Both these would give perfectly acceptable resolution for most purposes. I find scanning at 2400 spi is fine for web and laptop viewing. I suggest reading the linked review might help.
 
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