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Good Scanning Tips and Tutorial link

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  • Good Scanning Tips and Tutorial link

    I was researching a new scanner and found this site on my search. Check this out for some excellent scanning info.

  • #2

    Quite a lot of material on that link. As you may have gathered I've just got hold of a new HP scanner and I'm running it in tandem with the old one for comparison. The HP has the facility to scan transparancies so I've been digitising some work I did in the mid seventies which has been unseen for years.
    The results aren't bad considering the age of the transparancies and printoffs are good enough as handouts. The transparancies have been very carefully stored but some of the Kodachrome stock has started to deteriorate whereas a lot of stuff shot on Agfachrome shows no sign of decay. I wonder if that reflects on the film or the processing.


    • #3
      Hi Chris,
      I would think it is probably the film and not the process but I am no expert by a long shot on that subject.

      Glad you like the link. I thought this site would benefit alot of the members when I stumbled on it.

      I get my new scanner in the mail tomorrow. I am so eager for it's arrival. I went with the Epson Perfection 1650 Photo. It has the slide and negative attachment also. I was going to get a slide scanner because I already had a regular scanner but it started acting up on me so I had to get a new scanner. I decided to combine features. Went with Epson because I liked what the reviews said and because I have an Epson printer and camera so I figured the color profiles would be easier to match also. I'll let you know what it's like when I get it.


      • #4

        Just a guess, but I'd be inclined to think that the deterioration might be due to processing. Were the ones which show deterioration pretty much all processed at the same place? I've seen processing by *Kodak* fall short of perfection.


        Great link. Thanks much. I didn't have time to go through a lot of the material, but I did see one thing that I have a question about. Here is some text that was copied and pasted:

        >14.Scanning for the screen. Will the image be used
        for printing or for on-screen viewing? On-screen
        viewing is done at resolutions around 72 dots per
        inch (dpi). If your original is the same size as what you want the final result to be, just
        scan it at 72 dpi and you’ll have a perfectly sized screen image.<

        Wouldn't that depend on which resolution you have your monitor set for? It seems to me that if you have your monitor set for 640 X 480, you would get a much larger image than if you had it set for 1280 X 1024. And what about different sized monitors? Quite possibly my thinking on this is wrong, but I'd like to hear what others have to say. Am I missing something? Man, I hate it when I think I know something, then someone makes me think I might be all wet.



        • #5
          All the Kodachrome processing went to one plant in the UK in the seventies. But I recall a labour strike and I sent a lot of stuff to the German Kodak plant. Too late to worry about just interesting to look at long forgotten projects from years ago especially the nudes !!!


          • #6
            That's kind of what I thought too but I read somewhere that scanning for the web higher than 72 is a waste of time and pixels. I don't know why exactly other than larger files take too long to load on web pages. Maybe someone more familiar with web graphics could clarify that one.


            • #7
              Ed, Your thinking is correct. The important thing to remember when scanning for viewing on the screen is not the dpi but the absolute size in pixels. I've copied the following excerpt from the Scantips site:
              The useful way to think of monitor resolution is that our monitors show a fixed area of pixels, which is usually 640x480 or 800x600 or 1024x768. And the number that is important to describe video images is the X by Y image size in pixels, like 320x200 perhaps. For video, it is not important if that 320x200 image was scanned at 72 or 272 dpi. Either way the screen area consumed (320x200) will be the same (but for printing, it can matter). What is important for video images is the "X by Y" image size in pixels. Knowing this image size, we can judge how much of our 800x600 screen it will occupy. The same image will look larger on a 640x480 screen than on a 800x600 screen, and smaller yet on a 1024x768 screen. Larger or smaller meaning here to fill more or less of the total screen area.
              Wayne (the Scantips author) also has a page dedicated to the "72dpi Myth" which directly addresses your question with a big table of numbers.

              Hope this helps. -Jeanie


              • #8
                Thanks Jeanie. I knew I read something about that, and when you mentioned Wayne's site, it came back to me. He has an excellent site.

                What Jeanie said about the number of pixels is correct. I think what you're referring to is the fact that an 800 X 1200 pixel image at 300 ppi is *much* larger in file size than an 800 X 1200 pixel image at 72 ppi. When an image is displayed, it doesn't really matter what the resolution is, only what the pixel dimensions are. They will both display the same. That's why you don't want to send a higher resolution image.


                • #9
                  Hooray for Jeanie coming in and clearing it up for us.

                  I knew there was a reason but didn't understand the technicalities about it. Jeanie, what would we do with out you? I knew some one would be able to clarify the web aspect of things. I'm barely getting the handle on the print side of resolutions.


                  • #10
                    Still working through old messages...

                    Debbie, I'm glad that I could help. However, I think there are plenty of people on this site who could have helped - I just happened to be the first to answer.

                    Ed, To clarify something you said:
                    I think what you're referring to is the fact that an 800 X 1200 pixel image at 300 ppi is *much* larger in file size than an 800 X 1200 pixel image at 72 ppi.
                    Actually, an 800x1200 pixel image is the same file size regardless of the dpi. The thing that changes with the change in dpi is the print size - assuming the actual pixel size remains the same. E.g., an 800x1200 pixel image printed at 300dpi is 2.67"x4" (800/300 by 1200/300); the same image printed at 72dpi is 11.11"x16.67" (800/72 by 1200/72).

                    What you might be thinking of is the scanning process. A 4"x6" original scanned at 72dpi becomes a 288x432 pixel image (about 366K). Scanned at 300dpi it becomes a 1200x1800 pixel image (about 6.2M!) That is a huge difference in file size! (It's also a huge difference in size on the screen - but the print size will be the same, albeit of different quality.)

                    Hope I haven't confused things further.



                    • #11
                      Now Jeanie, I have to give credit where credit is due. You did come to the rescue with a fine explanation. However my brain takes one look at those numbers and sees a math problem. All of a sudden a red alert is sounded and up goes a wall to stop any further intrusion. I think that's why I tend to skim over that dpi vs size thing. But slowly with patient members on this site and it's managing to seap in.


                      • #12

                        What you said is correct, and I knew that. Don't know what I was thinking. I simply had a brain cramp! Thanks for straightening that out.



                        • #13
                          I had a feeling the numbers would only make things worse.

                          OK, bottom line (without numbers):

                          When scanning an original image, the dpi does affect the file size (and screen size).

                          Once you have the digital image, if the actual pixel size of the image remains the same, both the screen size and the file size remain the same regardless of the dpi. However, a change in dpi will change the eventual printed image size (in inches or centimeters - however you choose to measure.)

                          And if that doesn't help, just ignore this post and my last and go back to the point in time when you did understand.



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