Help sharpening/clarifying text

Discussion in 'Digital Photography' started by yojitani, Mar 29, 2009.

  1. yojitani macrumors 68000

    yojitani

    Joined:
    Apr 28, 2005
    Location:
    An octopus's garden
    #1
    I needed to photograph a page of an old broadsheet style journal because the people at the archive I went to did not have a scanner big enough. The image is not too bad, but I need to be able to shrink it and still be able to read the words. There are not a lot of words, by the way, it's not an article, its kind of like a board game. The problem is, of course, when I shrink it the words are difficult to read and I imagine will be even harder when I print out the page on an ordinary printer. Is there anything I can do to sharpen the text? I've tried using unsharp mask, but I'm not getting the results I want. What would work best, if possible, is tomake the print, which is the only black on the page, a little darker. Is there a way to do this? I'm not much of a photoshop buff!

    Thanks!

    p.s. tools at my disposal: photoshop and fireworks CS3, plus whatever Leopard has...

    edit 2: I hope this is the right forum! I figured this is where I would find people who use photoshop regularly.
     
  2. MisterMe macrumors G4

    MisterMe

    Joined:
    Jul 17, 2002
    Location:
    USA
    #2
    Primarily, your issues are hardware and optics-related, not software-related. You need a high-resolution digital camera, a flat mounting board to hold your pages to be photographed in place, a frame to hold the camera in place, and bright diffused [glare-free, shadow-free] lighting.
     
  3. yojitani thread starter macrumors 68000

    yojitani

    Joined:
    Apr 28, 2005
    Location:
    An octopus's garden
    #3
    Yeah, you're right. The archive is really using old technology. We actually had to place it on the floor because the mounting board they have is too small. And the camera was probably good for a snap and shoot in the early days of digital photography.

    I'm trying to arrange a second visit. I might be able to persuade them to let me take the material to a place with an oversized scanner... The problem is that these materials are rare and probably worth several thousand dollars at least.:eek:

    In the meantime, if there is anything I can do to work with what I've got, any suggestions would be appreciated.
     
  4. dmz macrumors regular

    dmz

    Joined:
    Jan 29, 2007
    Location:
    Canada
    #4
    Tough one - one solution that has worked quite well for us, though not with delicate archival material, is to scan or shoot the document in small sections and then stitch them all together in Photoshop. I'm sure there are other ways to do this, but this is tried-and-true.

    The two main problems with this technique are a) keeping your images "square", i.e. a level straight line drawn across the entire height or width remains straight and level, and b) maintaining a fairly constant source of illumination. It's easier to do a) with a camera, but the scanner is better at b). It's a real biXch trying to correct rotation after the fact, but illumination is not so critical if your primary aim is to "clean up" the text.

    If your aim is not to "reproduce" the piece, that is to make it appear just as as it is in its natural condition, but to increase the "readability" for human or computer eyes, then just two techniques in photoshop should help you substantially - the Levels control and the Unsharp Mask (USM) filter. The order of these two steps IS important, which I'll explain in a moment.

    This step assumes that your scanned or digitized images contain the full scale of greys. If not, go back and make sure you're working with images whose black and white points do not extend past the white and black points you see displayed in the "histogram" in the Levels tool's display. Okay?

    First, use the levels control to trim your white and black points. When I say white or black here, I mean the 100% black or white point. Set the white point so that most of the "paper" is "white", and set the black point so that just the darkest parts of the type are black". A useful technique to use here is holding the option- or control-key down while you drag the the adjustment triangles for the black- and white-point settings - you can gauge dynamically just how many pixels are turning "white" or "black".

    Convert the image to grayscale. Adjust the levels once more - same technique - you're just tweaking now to adjust for conversion. Now you can use the USM filter, setting the intensity somewhere between 100-200%, with 0 threshold, and adjust the radius to somewhere between 1-5 pixels.

    Your result should be fairly crisp, clear text - though this technique will also amplify any dirt in the original image. If you have a lot of time on your hands, you could try erasing all the "schmutz" with your eraser of choice.

    The order is important because the unsharp mask filter works based on contrast near edges, so maximising that effect before using the USM yields the best results - for this type of sharpening.

    If anyone has a better technique - I'd like to hear it too!

    dmz
     
  5. yojitani thread starter macrumors 68000

    yojitani

    Joined:
    Apr 28, 2005
    Location:
    An octopus's garden
    #5
    Excellent dmz! I will try this shortly. I did take photos of the page in question in small sections, but I flubbed on the angles in some shots so the stitching does not look professional enough. Your technique might work with the snaps I have though!

    Thanks!
     
  6. dmz macrumors regular

    dmz

    Joined:
    Jan 29, 2007
    Location:
    Canada
  7. yojitani thread starter macrumors 68000

    yojitani

    Joined:
    Apr 28, 2005
    Location:
    An octopus's garden
    #7
    Thanks for asking. I haven't had time to get to it! Just when I thought I could, something came up. I will keep you posted.
     

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