Scanning parameters?

[chanmalichan]

i'm scanning some old negatives and some disposable cameras for my friend using canoscan 8800f. Whats the optimum settings to get decent printable photos?

currently now i using output resolution 600dpi, input and output size is 1.42" x 0.93"

is that enough for a decent print?

Thanks!

[LM6er]

for normal print size like 4R, 300dpi is more than enough. ur output size should be 4x6inches then. however is u are also archiving the scans, better to scan at 600dpi or more.

[chanmalichan]

that means my scanning resolution is lousier than 300dpi coz my output size is small? That sucks man..

So how do i know when someone tells me they scanning at 300dpi or 600 dpi, whats the output size? Is it taken to be default 4by6 inch?

[chiif]

Originally Posted by chanmalichan i'm scanning some old negatives and some disposable cameras for my friend using canoscan 8800f. Whats the optimum settings to get decent printable photos? currently now i using output resolution 600dpi, input and output size is 1.42" x 0.93" is that enough for a decent print? Thanks!

If you are doing for archiving & printing purposes, scan at least 2400dpi.

[vince123123]

Scanning at 300dpi is wrong advice. 300dpi is on the assumption that you are doing a 1:1 scan; ie scanning a photograph.

In this case, you are scanning a tiny piece of negative and hoping to blow it up to a usable print. Even for 4R, the negative is blown up many times.

Hence, the advice to scan at 2400dpi or higher. What you can do is to measure the size of the negative; nevermind I tell you its 24mm x 36mm, approx around 1.44inches

Now to print 4R, that's 6 inches on the long side, so you are blowing up alomst 5x. To print 300dpi (the useful standard), at 4R, you need 1800pixels on the long side.

Now you divide 1800 by 1.44 and you get 1250. Hence you need to scan at 1250dpi minimum to print 4R.

Do the same math for the other print sizes you are intending to print. A good rule of thumb is to see what's the largest you think you'll ever print, and then scan that amount.

Most people however, use the kiasu method, and for me, I do that. I scan at the highest optical resolution that my scanner can cope (without interpolation). Hence, you see numbers like 2400dpi, 4800dpi and 9600dpi being common on film scanners.

[squall]

Hi, all the posters above are correct to some extent.

1. 300 dpi at 4x6 output is correct.
2. 1250dpi at 36x24mm output is also acceptable if printing to 4x6.
3. 2400dpi is also ok for 1.42"x0.93" if printing to 4x6

The point is the final outcome should approximate 300dpi AT THE FINAL OUTPUT SIZE. So the easiest is to set 300dpi and the correct output size ie dont set 1:1 or else you need to then go do the math as described by Vince. If you set 300dpi and the output size to be 4x6, the software will do the math for you, up to the limits of the scanner's resolution. So if your scanner is 4800dpi, you can set an output upto 16 inches on the long side before needing to compromise on the dpi (ie <300dpi).

My humble 2 cents.
Squall