Scanning Photographs

[billquinn]

I use xsane to run my HP Officejet 7310 All-in-One for scanning. I hope it's okay to ask this--you see, there's nothing malfunctioning; I just didn't know where else to get some advice.

I'm scanning a wallet-size photograph. Is it always best to scan with a high resolution, say 600, even if the photo is physically small? I would think that to achieve equal quality, the number of dots per inch should be the same regardless of the dimensions of the photo being scanned. However, when I scan this small photo at such a high resolution, it doesn't seem to look too good on the screen. A scan at a resolution of 200 actually looks better. I don't understand this.

Any rules of thumb about such things?

[RonPolley]

Hello billquinn,
If your scanning to view on your monitor use 100 dpi as most monitors only render from 74 to 101 dpi. anything above that is compressed and lost in the view. To see the actual difference of varied dpi scans you must print them or view them magnified with your photo viewer.
It's foggy here in New Bern
Ron

[Dan]

Bingo!

Ron's got the way of it. However, if you are going to print them at all, use 400 or better dpi for magazine work, 200 dpi for newsprint (which is the norm ... but a total waste. I've never seen a web press that could get anywhere close to that detail. <....> ) or scanner max for serious photo printing. Then when you pull it into your GIMP or Cinepaint editor ... you've got some detail to work with. You can always shrink them down from there. (Depending on the shot and the starting size, it's best to shrink in stages, and adjust sharpening and contrast after each stage.)

A caveat, though. It's incredibly easy to over-run your available ram when working with large images. Best to trade off detail for ability to actually work with the image. I use a full 2 gigs of ram on my image editing machine.

[billquinn]

Thanks so much, Ron and Dan, for some really great suggestions. I'm just a novice at this kind of thing--and so far all I know how to do with the GIMP is crop and scale!!!

[Dan]

LOL!

That's Kinda like using a precision scroll saw for a framing hammer!

The GIMP is incredibly powerful ... in the right hands. And, as usual, it's the quality time spent with the documentation that makes the difference with the hands.

Which, by the way, can have other consequences too. Case in point ... Things are not always what they seem.


Before:


After:


<....>

[billquinn]

Clever analogy!

And I am most impressed with the picture! Getting rid of the parking sign like that. Amazing!

Very cute little girl, Dan. Is she yours?

[Dan]

Nope. Kinda wish she was, though. She's the baby daughter of a helluva good ranching family in Southeastern Colorado.

This was shot at the summer festival parade year before last. Both her mom and dad were riding just out of frame here in front of her, and although you had to look close to see it, they were both so proud of her they were about to bust. <....>

The GIMP is also really good for graphics design. These were created entirely in the GIMP:

http://forums.fedoraforum.org/album.php?albumid=2