On 12.02.2010 14:16, emre wrote: > abel deuring wrote: >> *On 12.02.2010 05:12, emre wrote: >> >>> >>> I have one more question, it has to do with resolution. The fi-6130 >>> reports a 600 dpi >>> resolution (which seems to me to be more than sufficient). I have seen >>> some Epson >>> scanners that report 6400 dpi. I am guessing that higher resolution >>> might be good >>> for slides and photos, but wouldn't be of much use for scanning >>> documents? >>> Thanks again, >>> >> >> I have serious doubts that even any affordable slide scanner really has >> such a high resolution; for a scanner that can scan an A4 or letter size >> document, 6400 dpi sounds ridiculous. You would need very precise and >> expensive optical and mechanical components to really achieve such a >> high resolution. >> >> Also, consider the size of an A4 size scan with 6400 dpi: That would be >> 210*297*6400*6400/(25.4*25.4), nearly 4 billion pixels. IOW, you could >> fill a terabyte disk with just 250 uncompressed gray scale images... >> >> Typical scan resolutions for A4/letter size are 200 or 300 dpi -- what >> you need depends on your use case, the number of scans you want to store >> and on the storage capacity you can and want to afford. >> >> Abel >> >> > I just verified at the epson.com website for the Epson Perfection V600 > printer, and they > do report 6400 dpi for their optical resolution. Granted, it would take > a lot of disk space, > but it would also seem beneficial to have this resolution for archiving > of slides and negatives.
Sure, it might be nice to scan slides with that resolution. But even then: IIRC, the "resolution" of most slides is more like 2000dpi than 6000dpi. So, unless I am completely mistaken about the, how is is called, grain size?, of slides or negatives, 6400dpi looks a bit pointless. Also, I'd be really curious how a scan of a high-quality Siemens star (http://en.wikipedia.org/wiki/Siemens_star) looks like for these allegedly possible 6400dpi. Frankly, I'd suspect that the image will look quite blurry, if you look at it closely enough. > Now, if they really have this resolution, I can not say... & I am I can't say either, of course ;) Sure, I believe them that the _data_ produced by scanner will have 6400dpi resolution -- I just doubt that you can really get such an _optical_ resolution with a scanner that costs less than, let's say, a good second hand car... Abel
