Maybe my math is bad; but if it has a native resolution of 2400 ppi/dpi scanning 1" film, then my math says it will have a native resolution scanning a 5 inch subject which is much lower than 300 ppi/dpi independent of the light path factors(e.g., around 75 ppi/dpi). For the size print that the original poster mentioned which was smaller ( but I forget the exact size but I think it may have been either a 3.5 x 5 or a 4 x 6), the native optical resolution would be in the range of about 150 ppi/dpi to 300 ppi/dpi.
But this is based on the assumption that a scanner can have variable native optical resolutions; however, to the best of my knowledge and understanding, scanners have a single native optical resolution. The effective optical resolution is a by-product of the number of inches that one divides into the native optical resolution. Thus, an enlargement of the image without any interpolative resampling will result in a lower effective resolution while the reduction of the image size without such sampling will result in a higher effective resolution. Nevertheless, it is still unclear to me if you are saying that the native OPTICAL resolution of this scanner is variable or not; and if not, if the native OPTICAL resolution of this scanner is 2400 ppi/dpi or something else that would produce an effective native resolution of 2400 ppi/dpi when scanning a 1 inch horizontal length as opposed to some other horizontal length. ----Original Message---- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Arthur Entlich Sent: Monday, August 08, 2005 4:45 AM To: [EMAIL PROTECTED] Subject: [filmscanners] Re: HP PhotsSmart - questions > The native optical resolution of this scanner varies > dependent upon the size of the image being scanned. In the > case of 35mm film, which is just under 1" wide, the scanner > sensor/CCD scans at 2400 ppi/dpi. > However, when switched to reflective mode, the scanner can > scan up to 5 x 7" prints (I previously incorrectly noted > 4x6"). In this mode the maximum is 300 ppi/dpi (although the > math implies it could scan up to about 450 ppi/dpi) but who > knows what kind of optical light path bending they had to do to > accomplish that. > > Art > > Laurie Solomon wrote: > >> I looked at the web site you gave the link for; it was not clear from >> its contents as to what the unit's native optical resolution is. If >> the native optical resolution is 150 dpi and the other resolutions >> are all interpolations, that might account for the reason that the >> 150 is sharper than the 300 dpi. Moreover, the screen resolution >> might also enter into the equation since the screen rendering of the >> image will be such as to make the 300 dpi scan be rendered on the >> monitor at twice the size as the 150 dpi scan which can result it >> some apparent fuzziness with the smaller rendering appearing sharper >> even at lower resolutions. >> >> The standard rule of thumb sage advice is to scan at the scanners >> optical resolution and not at an interpolated resolution to get the >> maximum sharpness and the minimum flaws, artifacts, and noise. >> >> But you have me a little confused. You speak of scanning a 3x5 >> print; but then you say you also had this negative roll scanned at >> Target. Are we talking about positive paper prints or film >> negatives? They are two very different things. >> >> Unless you will be enlarging a hard copy print to a print size larger >> then the original or a portion of a cropped print to the size of the >> entire original print or larger, a 300 dpi is sufficient since hard >> copy prints typically do not yield resolutions greater then 300 dpi >> since the information is not there in the original to support a >> higher resolution with actual original data. To scan 35mm film, one >> will normally scan it at a resolution of around 4000 dpi since the >> frames will typically be enlarged to at least 3.5 X so as to produce >> a 3.5 X 5 image at around 300 dpi. A 1200 dpi scan of a 35mm film >> frame is a relatively low resolution to be scanning 35mm at and >> would require interpolation in the event that one wanted to enlarge >> the image in its entirety or in part. Thus, Target is really not >> doing any better than your machine would do on a 35mm film frame. >> Moreover, we do not know if the 1200 dpi that Target scans at is >> real optical > resolution or interpolated resolution. >> >> >>> -----Original Message----- >>> From: [EMAIL PROTECTED] >>> [mailto:[EMAIL PROTECTED] On Behalf Of Rich Koziol >>> Sent: Saturday, August 06, 2005 1:01 PM >>> To: [EMAIL PROTECTED] >>> Subject: [filmscanners] Re: HP PhotsSmart - questions >>> >>> On 6 Aug 2005 at 12:06, Laurie Solomon wrote: >>> >>> >>>> As for the question of " why 150 dpi appears sharper than >>> >>> 300 dpi when >>> >>>> scanning a 3 x 5 color print," you did not tell us if the >>> >>> result you >>> >>>> speak of was on the monitor or on a hard copy print >>> >>> At this point I'm just looking at the results on a 19inch monitor. >>> Used the HP software to scan with. >>> >>> I also had this negative roll scanned at Target, for comparison. >>> Target offers 1200dpi scans for about $4/roll. They just started >>> this service and are still somewhat sloppy with film handling. >>> >>> Rich >>> >>> -------------------------------------------------------------- >>> -------------------------- >>> Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe >>> filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) >>> in the message title or body >>> >>> -- >>> No virus found in this incoming message. >>> Checked by AVG Anti-Virus. >>> Version: 7.0.338 / Virus Database: 267.10.1/64 - Release >>> Date: 8/4/2005 >>> >>> >> >> >> -- >> No virus found in this outgoing message. >> Checked by AVG Anti-Virus. >> Version: 7.0.338 / Virus Database: 267.10.1/64 - Release Date: >> 8/4/2005 >> >> >> >> > > -------------------------------------------------------------- > -------------------------- > Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe > filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) > in the message title or body ---------------------------------------------------------------------------------------- Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body