Go Back   Steve's Digicams Forums > Digicam Help > General Discussion

Thread Tools Search this Thread
Old Dec 14, 2002, 8:41 PM   #1
Senior Member
Join Date: Sep 2002
Posts: 135
Default Scanning Photos at 300 DPI How do I Get file Size Down?

I have a Older Canon FB 620P scanner and I have to scan at 300 DPI in order for the photos to look good, anything less than 300 DPI looks grainy, that was always the way this scanner worked best.
The problem I have is when I save them, they are almost 2mb each and that is when I am scanning wallet size photos, it goes up to 10 or 12 MB when I scan an 8X10!, even when I saved them as JPG's, how do I make the file size smaller so I can email them?
I tried to "resize" them in MGI Photo Suite 4 but than only part of the picture is shown. Can I save them at 25% instead 100%, I know the quality will go down the tubes, but I do not know how else to get the file size smaller, unless I take a snapshot of the photo with the Coolpix 2500 and send it out as a small picture, but that defeates the scanner.
Corn-fused. :?
Bill Benson is offline   Reply With Quote
Sponsored Links
Old Dec 14, 2002, 10:15 PM   #2
Senior Member
Join Date: Jun 2002
Posts: 172

Your DPI is still way too low.. Perhaps a scan of 2400 dpi would be better for a small sized photo but it really is an intrinsic value. Size (reproduction) vs (resolution) vs (size). Now after the scan is it .tif or .jpg? Sharpen after reproduction ? Necessary... and on and on....
M. Haner is offline   Reply With Quote
Old Dec 14, 2002, 10:24 PM   #3
Join Date: Nov 2002
Posts: 62

You should be scanning at more than 300dpi if you can to get the best quality. From your description it seems what's happening is the 'canvas' size is being reduced not the image itself. The result is you only see that part of the oversized image that overlaps the 'canvas'. I don't know MGI Photosuite but there must be some way of adjusting the pixel dimension of the scanned image. If you reduce it down to around 2,500 pixels wide and save it as a jpeg at not less than 80% quality you should end up with a reasonable size file around 1 megabyte or so. Of course adjust the pixel dimensions according to your intended use for the image. For emailing I would drop it down to about 800 pixels wide maximum.
Richard Howes is offline   Reply With Quote
Old Dec 15, 2002, 2:44 PM   #4
Senior Member
Join Date: Sep 2002
Posts: 135

I am still confused, if I scan at that high of a scan rate, 2400 DPI, the photo would be 60 or 70 MB! When I had my old Plustek scanner I used to scan at 150 DPI and got beautiful photos, I still have those pictutes in my computer. But in order for me to get photos that look as good as that old Plustek that I scanned at 150 DPI, on this canon I have to scan at least 300 DPI, I tried to scan at 600 DPI but the photo was HUGE in file size, and they are all Saved as JPG's.
When I try to print a huge size photo (10 or 20 MB) the program will not respond.
There has got to be a way to scan at 150 DPI like my old Plustek and get good photos.
BTW as mentioned my Canon is a FB-620P and it uses "canon Image Trust" from the MGI program I guess, not sure how that works, guess it is twain, anyway I have been using it right along.
As far as reducing the file size, I still am not sure what you mean.
Thanks for the information.
Bill Benson is offline   Reply With Quote
Old Dec 15, 2002, 5:08 PM   #5
Senior Member
Join Date: Aug 2002
Posts: 2,162

I wrote a long reply, but lost it when I realised I hadn't logged in. Here's the short version.

A useful little formula to OPTIMISE your scanner dpi, to produce a 2Mb file to email, based on 18:1 JPEG compression, i.e an uncompressed file size of 36Mb.

36Mb =4500000 MegaDots. Divide this by (WidthXHeight) inches of your image to be scanned and take the square root.

So a 6X4 print should be scanned at 433dpi. If your pc is only up to a 20Mb uncompressed file, then you should scan at 322dpi. Think about uncompressed files size first, this is what takes memory for editing, processor speed and all the time for printing out on a slow printer. Your pc needs at least 128Mb RAM, preferably more. Just because a scanner says it will do 2400dpi, doesn't mean you have the kit to do this on an A4 size print!

If you're really keen on 150dpi when most of us strive to make the least compromise for best quality, you can always scan at 300dpi do your editing, BUT BEFORE SAVING AS A JPEG, down sample to 150dpi.

You say your images are HUGE. Well they will be. Your monitor is about 72dpi. So a 300 dpi file will be 4 times the screen size! that's why you tell the editor package to zoom or fit the image to window.

If you only want to send somebody a pic. to view on a monitor and you want to make sure it opens at full size, you only need to down sample or scan at 72dpi.

A major factor in determining resolution/compression ratio/file size is to decide whether you just want your images viewed on a monitor, in which case 72dpi is o.k. Or you are sending the best small file you can, for printing at the other end.
voxmagna is offline   Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

All times are GMT -5. The time now is 8:52 AM.