I scan films by V700 with the following settings:

Scanning software : Silverfast (Epson SE)
Scan type : 24 bit color
Image type : Landscape
Filter : Auto Sharpen

My film : 6x8mm (Fujifilm velvia 50)

1st scan : 6400 dpi that gives a 733 MB file. Open it in Photoshop 7.0 and enlarge to see the actual pixel, i.e. 100%, the image is not clear and sharp!

2nd scan : 2400 dpi that gives a 103 MB file. See it at actual pixel, image not clear...

Then, I try to scan at different dpi, such as 1800 and 1600 dpi, no luck...

Finally, scan at 1200 dpi which gives a 25 MB file, the image is sharp at actual pixel.

My questions are:

1. if I bring that 733MB file to printing company to get a 24"x30" print by photo paper, will the image be sharp?

2. if I bring that 25MB (1200 dpi) to have a 24"x30" print by photo paper, will the image NOT sharp?

3. Why not the image be sharp when scanned by high resulotion?