Photo scanning resolution

entropyentropy Yah-Der-Hey (Wisconsin)
edited September 2004 in Internet & Media
Now, for regular, color photos, what resolution should I scan at? My photography teacher said 150 DPI is good, but, well, our school's scanners are trash and the computers don't have enough hard drive space, so it could be a conservative guess. What do you guys usually use? I can go from 50 DPI all the way to 4800 DPI, and also, should I have it automatically "Reduce Moire" (whatever that is)? I'm using the Visioneer Scan Manager Pro and having it drop the pics right into PS. For some reason, I can't select the "AutoScan" button anymore (??) so I'm doing it myself.

Comments

  • primesuspectprimesuspect Beepin n' Boopin Detroit, MI Icrontian
    edited September 2004
    4800 dpi is fake. THe scanner's optical resolution (the true resolution) is probably 300dpi, maybe 600 if it's newer or high end.

    If the final destination is for the web and you will NEVER print it - scan 96dpi

    If the final destination MAY be printed - scan 200 dpi.

    300dpi is for national geographic and maxim. Don't worry too much about it if file size is a concern. if you have unlimited space and just don't care, go 300dpi, it can't hurt. Bigger is better.
  • Nolf-JobNolf-Job Inside each and every one of you!
    edited September 2004
    It really depends on what you're doing with the photos. If you're going to be doing a lot of touch-up work and the like you'll want a higher resolution. If you're going to be editing them and then reprinting them out, you'll also want a higher resolution (at least 150 dpi, but I'd go higher). Otherwise, if it's just stuff for the web or something like that use 72dpi.
  • RWBRWB Icrontian
    edited September 2004
    I scan at 1200dpi ;) But usually only go with 600, depends on what it lets me do. The higher the batter I say.
  • entropyentropy Yah-Der-Hey (Wisconsin)
    edited September 2004
    These may or may not be on the web or anything, and they will most likely be either printed or just stored on disc. I finished scanning them all at 150 DPI, so do you think I should redo them in 300 (edit: or higher)? Won't take a whole ton longer ... btw ... what do you mean it's 'faked'? What does it do? (My scanner is a brand new Visioneer OneTouch 7100 USB, btw)
  • primesuspectprimesuspect Beepin n' Boopin Detroit, MI Icrontian
    edited September 2004
    It's called interpolation. The scanner actually sees one pixel - and then the software splits the pixel up into four, eight, sixteen, whatever.... It then looks at the pixels surrounding the original pixel and blends the edge colors to acheive a smoother look and get higher resolution. But the problem is, it makes the files enormous (for example, an 8.5x11 full page scan at 300 dpi would be around 35mb, while a 2400dpi 8.5x11 would be over 2 GIGS), with no actual benefit as far as output is concerned. It's totally useless. Nobody would scan anything over 1200 dpi - and 1200dpi would be line art only. 600 dpi for full color on a consumer-level flatbed scanner is the highest practical resolution. when you go into four-digit resolutions and you are talking about scanning, you are working with a drum scanner at a high-end service bureau (for pre-press work)

    (yes, I come from the printing industry :( )
  • entropyentropy Yah-Der-Hey (Wisconsin)
    edited September 2004
    Alrightay. I rescanned everything at 300 DPI. Now. I'm gonna be sending these to a few friends, and plus I might want them printed some day. So. Not JPEG, correct? What then? PNG? TIFF? TIFF is the best, but the files are just massive. So what should I do? Keep TIFF for printing, JPEG for sending? :confused:
  • entropyentropy Yah-Der-Hey (Wisconsin)
    edited September 2004
    *bumpity bumpbump*

    Heh. Guys? Photoshop doesn't like holding open 40something [relatively] hi-res pics :p Lookit my RAM left lol, I need to save these!
  • primesuspectprimesuspect Beepin n' Boopin Detroit, MI Icrontian
    edited September 2004
    Jpeg for emails, tiff with LZW compression (LZW is non lossy) for archival/printing purposes.

    300DPI images are massive, there's no way around it.
  • entropyentropy Yah-Der-Hey (Wisconsin)
    edited September 2004
    Lol, too late :p. I got sick of dragging along with no ram, so I saved them all as tiff with NO compression. Time to resave! ;D Uh ... is there any way I can save a mass of pictures as a certain type...? I don't look forward to reopening and resaving 31 images ;) (Btw, yes, I do want to do LZW ... it saved ~2 megs per file :))
  • primesuspectprimesuspect Beepin n' Boopin Detroit, MI Icrontian
    edited September 2004
    You could create a batch droplet, but that would take longer than opening and saving 31 pictures.
  • botheredbothered Manchester UK
    edited September 2004
    I scan pics at 200, 300 if I'm printing them large and I always save them as jpegs. Epson gt5500 and Epson 925. No probs.
  • DexterDexter Vancouver, BC Canada
    edited September 2004
    A good, but long tutorial on scanning:

    http://www.scantips.com/basics01.html

    Also, for quick and easy file conversions and re-sizing, I like ClickPic, which adds a right-click context menu for those and other tools right in the Windows Explorer shell:

    http://www.smalleranimals.com/saclickpic.htm

    The free version keeps working after the trial date, you just have to ignore a short Nag screen after the trial ends.

    Dexter...
  • primesuspectprimesuspect Beepin n' Boopin Detroit, MI Icrontian
    edited September 2004
    Oh, I forgot to add, Picasa (free from google) can do simple resizing quickly. It recognizes tiffs, so that'll work for you.

    www.picasa.com
  • GHoosdumGHoosdum Icrontian
    edited September 2004
    If all you're looking for is resizing, you can download the Image Resizer from the Windows PowerToys site. It adds "Resize Image" option to the right-click context menu for image files. It doesn't do file type conversions, though.
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