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Thread: question about photoshop USM

  1. #1
    Senior Member erictan8888's Avatar
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    Default question about photoshop USM

    when i photoshop my pics, the last 2 steps are normally USM....

    for last 2nd step: i use radius of 0.8 and about 70% or so...
    for last step: i use radius of 20 and about 15%

    question: any difference if i switch the order of the last 2 steps ? (that is, use radius of 20 first, followed by radius of 0.8 for USM)

    pls advise.... thanks
    Hope to learn from everyone here....

  2. #2

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    Quote Originally Posted by erictan8888
    when i photoshop my pics, the last 2 steps are normally USM....

    for last 2nd step: i use radius of 0.8 and about 70% or so...
    for last step: i use radius of 20 and about 15%

    question: any difference if i switch the order of the last 2 steps ? (that is, use radius of 20 first, followed by radius of 0.8 for USM)

    pls advise.... thanks
    don't have to run USM twice. View the photo at least at 50% or larger to see the effect as you adjust the viarables of the USM (amount, radius, threshold). After USM, go to Edit > Fade USM >change the mode to luminosity (this step is to prevent colour shift).

  3. #3
    Senior Member erictan8888's Avatar
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    sorry, but what does fade USM actually do? dun quite understand the prevent color shift thingy...

    also, how much to set for the opacity in fade USM ?

    i thought USM is to sharpen the pic, then why want to fade it ?

    pls advise... thanks
    Hope to learn from everyone here....

  4. #4

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    Quote Originally Posted by erictan8888
    sorry, but what does fade USM actually do? dun quite understand the prevent color shift thingy...

    also, how much to set for the opacity in fade USM ?

    i thought USM is to sharpen the pic, then why want to fade it ?

    pls advise... thanks
    leave opacity at 100%

    when we use USM it will apply to all the colour channel - Red, Green and Blue thus it will affect the colour.

    but when you apply fade USM > Luminosity it will only apply in the lightness channel (Kind of Black and white channel of your photo) thus it will not have colour shift.

    for experiment open an image apply an extreme USM > amount: 200, radius:24; threshold:0. Then go edit> Fade USM > mode:luminosity> opacity: 100% - select and deselect the preview and look at the image you will get what I mean.

  5. #5
    Senior Member erictan8888's Avatar
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    Default

    thanks for your infor....

    just like to check:
    if my normal USM is applied at about 70 to 80% at most for a radius of 0.8, am i right to say that the colour shift, if any, is hardly noticeable to the normal eye ?

    thanks
    Hope to learn from everyone here....

  6. #6

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    Try in PS switching the image to Lab mode and do the USM on the Lightness channel only. See if you prefer the result.

  7. #7

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    One of the stages of USM that you've mentioned is to remove haziness... I usually do that before everything else...
    My typical value is 30 rad, 20%...

    After doing all editing, then you use the final 0.8-2.0 rad, approx 80%-120% amount.
    The amount to use depends on what kind of picture it is... ie.. if it's a full face shot, then your rad should be closer to 2.0.. if it's a photo with lots of detail, ie group photo, you may use something closer to 0.8 rad...

    Remember these are guidelines.. there are no hard and fast rules about USM...

  8. #8
    Senior Member erictan8888's Avatar
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    thanks.....

    one think about USM to remove haziness.... if i do that before anything else, will pic be affected if after this step, i do levels, curves and saturation....
    i mean, will the haziness return due to adjusting the levels, curves, saturation ?

    i notice that quite a number of users who post model shots say they touch up the face skin tone to make it more smooth.... what do i do if i want to make the complexion of people in my shots look smooth ?

    pls advise...
    thanks
    Hope to learn from everyone here....

  9. #9

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    Quote Originally Posted by erictan8888
    thanks.....

    one think about USM to remove haziness.... if i do that before anything else, will pic be affected if after this step, i do levels, curves and saturation....
    i mean, will the haziness return due to adjusting the levels, curves, saturation ?

    i notice that quite a number of users who post model shots say they touch up the face skin tone to make it more smooth.... what do i do if i want to make the complexion of people in my shots look smooth ?

    pls advise...
    thanks
    No.. the haziness will not return for the USM that you did for step 1..

    One method for making a smooth skin tone is to create another layer, use gaussion blur on that layer till you can't see any defects... then change the opacity of that layer to about 70%. You can then use layer mask to selectively apply to only the skin areas... one quick way to create that mask I use is to select colour range and keep adding the areas of skin. Then apply the layer mask on it... I will then modify the mask by hand for those areas that have been missed out or needed to be added in..

  10. #10

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    Quote Originally Posted by erictan8888
    thanks for your infor....

    just like to check:
    if my normal USM is applied at about 70 to 80% at most for a radius of 0.8, am i right to say that the colour shift, if any, is hardly noticeable to the normal eye ?

    thanks
    yes, it is almost undetectable because of the limitation of the monitor.

  11. #11
    Senior Member erictan8888's Avatar
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    wow... thanks a lot.... feeling super "enlightened" by all the ans....

    thanks again....
    Hope to learn from everyone here....

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