sharpen vs unsharp mask & proper usage.

Discussion in 'Digital Photography' started by jmc, Jan 23, 2005.

  1. jmc

    jmc Guest

    Question on sharpening. I have a choice of various sharpen levels,
    including directional, plus a couple levels of Unsharp Mask, and
    Unsharp Mask Gaussian in the program I mainly use for light image
    processing, ThumbsPlus. I also have Photoshop Elements, which I use
    when TP can't handle the job.

    Now, I've read here that most digital images can benefit from
    sharpening. I mainly use the Gaussian version.

    However, I've been wondering - when is it appropriate to use sharpen, as
    opposed to an unsharp mask? When is Gaussian not a good idea (and how
    is it different than the regular version?) Which one is better to try
    to fix a slightly motion-blurred image, as opposed to a slightly
    out-of-focus image? When would a directional sharpen work?

    If I have a photo with noise that needs to be sharpened, do I sharpen
    first then reduce noise, or vice versa?

    If there's a place I can go to read about this, please point me there.

    Appreciate your help.
     
    jmc, Jan 23, 2005
    #1
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  2. Charles Schuler, Jan 23, 2005
    #2
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  3. jmc

    paul Guest

    I'll have to check that out. Those video tutorials are great.

    My understanding is 'regular' sharpening is just a generic light sharpen
    that normally works fine. If it's not OK, use unsharp mask & set a
    radius of just 1/3 to maybe three pixels & intensity of around 300. I
    never messed with threshold.

    Zoom in to 800% (control-plus) so you can see exactly what's happening
    and you will understand intuitively while playing with the sliders.

    Sharpening is always done last as it will otherwise emphasize the noise
    or colors you are trying to adjust away. It needs to be done for each
    time you reduce (even thumbnails) though it's not clear to me there is
    any damage in sharpening the large one then re-shaprening for web/email
    versions it perhaps is not ideal.
     
    paul, Jan 23, 2005
    #3
  4. jmc

    Tony Guest

    Tony, Jan 23, 2005
    #4
  5. jmc

    Stacey Guest

    Depends on how soft the original is. I found if it's TOO soft, when you go
    to adjust levels or contrast it can wipe out details. Some need a touch
    before you get to work on it (or set slightly sharper in camera/RAW
    conversion) and then a final sharpening before printing.


    I've also found sharpening looks better done in stages rather than all at
    once, just like with resampling.

    Try this on the next image you need to sharpen (read this somewhere..)

    Set unsharp mask amount to 10-15%, radius to 50, threshold to 0 and apply.
    Then do another at 40-80%, radius to 1.5-1.8, theshold to 5-8 and apply and
    see what you think. Might need to play with the % depending on the image
    and your taste. Each sharpens different parts and really wakes up the edge
    contrast. It's a very useful technique.
     
    Stacey, Jan 24, 2005
    #5
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