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What sort of Scanner Supports supports 9600 Dots Per Inch (DPI)?

CP/M User

CP/M User

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Well?

The scanner I have which is one of those Printer/Scanner combos was scanning some old photos of mine, when I scanned them at 300 DPI (which is the factory default) they looked pretty good. For one of them though I was selecting a portion of the image and scanning it at 900 DPI which looked shocking. What I'm unsure about is was it the limitations of the photo which was making it look bad or the limitations of the scanner.

I dare say I wasn't game to try scanning at 9600 on my computer, last time I tried doing this on the computers at school I nearly blew the CPU and HD apart. I'm unsure if those scanners can do 9600 DPI or perhaps you need the memory to scan in that kind of detail.
 
As far as I know, many cheap scanners can interpolate into those resolutions. That means the scanner will calculate which pixels should be between two that it it scanned. There may be somewhat expensive scanners which optically scan in that detail, though I don't know in which application you need to do it.
 
Slide scanners routinely work at 2400 DPI, but slides and negatives are far smaller than what general purpose scanners are used for, so the resulting file sizes are still manageable.
 
IN the HP scanners, even up to $1500, they have an optical resolution of a max of 4800dpi.

they DO have a $99 scanner (G3010) that does up to 4800 optical.

HP's lineup:

http://h10010.www1.hp.com/wwpc/us/en/sm/WF02a/15179-15179-64195.html

I have a Fujitsu ScanSnap at work, although I don't think Fujitsu makes anything much above 600dpi (that's even remotely affordable, at least)

I'd check Epsons and Canons and see what they have.


Tony
 
If I was buying a high-end scanner, I would be more interested in colour reproduction and overall sharpness than the number of dots per inch it can scan. If it is all blurry with washed out or wrong colours, it doesn't matter much if it is a 50000 dpi scanner.
 
carlsson wrote:

If I was buying a high-end scanner, I would be more interested in colour reproduction and overall sharpness than the number of dots per inch it can scan. If it is all blurry with washed out or wrong colours, it doesn't matter much if it is a 50000 dpi scanner.

That's true. Some of the photos I've done on the scanner I have access to (which is an Epson CX4700 which probably mean's very little to you) seems to have improved the photos in terms of colour contrast. On one of them there's a large grey boulder which is in a variation of Grey's with some moss on it. On the original photo it appears quite dark and it's hard to pickup, though when I scanned it in, it looks more like what I would have seen at the time.

Perhaps too much detail could be a bad thing. I guess my main query is if I selected an area to scan it as part of a photo, would scanning it in a scanner which can do 9600 DPI have an effect of blowing up a area (like a Zoom effect on a camera) or using a magnifier? I feel this more likely wouldn't occur because of the limitations of the photo - it's impossible to put something there when you can't see it for instance.
 
At some point zooming into a photo would just show the grain size of the dots that make it up, you cannot see more then what was originally printed.

I have a USB (3400) and SCSI (1200s) Umax scanners and they do 1200 DPI optical which is pretty decent, and 9600 interpolated which is overkill.

Anybody doing heavy scanning needs to have a copy of photoshop to do auto leveling of the picture so the colors look correct (even if it is a very old copy). Even good scanners need help sometimes with getting the colors correct.
 
Unknown_K wrote:

At some point zooming into a photo would just show the grain size of the dots that make it up, you cannot see more then what was originally printed.

Hmmm, wouldn't that mean that the 6x4 photos I've been scanning in would come out more pixelated if I wanted to go bigger than a 6x4 photo sheet?

The 6x4 photos I scanned in I reckon would look good on an A4 sheet (I know my panoramic photo does! :-D)

Perhaps I worded it wrong when I said zooming in on something and meant to say enlarge something within a photo. Zooming something would inevitably pixelate an image, though would enlarging do the same thing? I only ask because I was watching this old film (which I doubt many people might have seen here) done in the late 40s titled "Call Northside 777" (or Calling Northside 777 I think it's called in the U.S.) which featured an early process of enlarging a photo to get this innocent guy out of gaol (this movie is based on a true story funnily enough). The text they wanted was from a 6x4 photo and when they got it into readable vision the text was blurry though this seem to be coming out of a photo where you couldn't see the text initially. So of course it really makes me wonder what sort of stuff you can get out of a photo.

Anybody doing heavy scanning needs to have a copy of photoshop to do auto leveling of the picture so the colors look correct (even if it is a very old copy). Even good scanners need help sometimes with getting the colors correct.

If Paint Shop Pro any good? Photoshop is and has always been overkill in terms of price, or is there a Freeware equivalent? (I've recently downloaded a Freeware Image program handy for image manipulation - though perhaps does photos, haven't tried it out yet!). Personally I'd rather have something 'free' than some bootleg.
 
I think fiction enhances reality sometimes. Personally, I find blurry text easier to recognize if it is zoomed out than zoomed in. Take some scanned picture of e.g. an old computer you're trying to identify the model number. If you zoom almost into pixel level, you can't make out anything.

This topic leads me into the discussion how many megapixels a digital camera needs to have to compensate for the resolution of a traditional 35 mm film camera. There probably are a lot of factors such as light, quality of film, optics and so on, but I've read figures that about 6-8 megapixels correspond to the maximum resolution you can get from a 35 mm camera, if processed well and printed in high resolution.

To get back to the scanner question, I'd believe it doesn't make sense to scan in a much higher resolution than it once was printed in? Many newspapers seem to use a 200 dpi raster, so scanning from a paper should not make much difference if you exceed that number?
 
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