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Currently Being Moderated

Content Aware Delete?

Aug 2, 2012 9:25 PM

Tags: #content #live #8 #aware #delete #bit #selections #16

I am aware that on a 16 bit image, live selections (think marching ants) once adjusted are immediately rendered 8 bit (and now quite prone to posterization issues).  Live selections, unless turned into a mask are very destructive, when adjusted.

 

Having said that, it is my suspicion that by using quick mask to make various selections, to delete (using CONTENT AWARE DELETE) will also render the live selection areas 8 bit.

 

Is that true?

 
Replies
  • Currently Being Moderated
    Aug 2, 2012 10:14 PM   in reply to ACRFREAK

    The mask for the selection is 8 bit.

    But the selection mask does not affect the precision of the image data.

     

    I'm not sure what you mean by "live selection areas".

     
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  • Currently Being Moderated
    Aug 3, 2012 11:58 AM   in reply to ACRFREAK

    The selection mask is 8 bits, regardless of the document precision.

    That fact has no effect on the precision of the image.

    No, it won't change the image or cause future posterization -- the image data is still the same precision as it always was.

     
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  • Currently Being Moderated
    Aug 3, 2012 12:00 PM   in reply to ACRFREAK

    A mask in a 16 bit image is 16-bit. A selection made from a mask in a 16 bit image is 8 bit. So depending on what you want to do, it's technically better to erase something via a layer mask vs an 8-bit selection and a delete. But the odds that you could EVER detect the differences is very slight. Where 8-bit selections can be problimatic is where you alter or manipulate the actual selection. The engineers looked at updating 16-bit image selections to 8-bit but the need to do so was never really proven–if you can prove the need, I'm sure Chris will look into the issue.

     
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  • Noel Carboni
    23,469 posts
    Dec 23, 2006
    Currently Being Moderated
    Aug 3, 2012 12:10 PM   in reply to Jeff Schewe

    <shudder>  Changing selection masks to be anything other than 8 bits would break everything.  Even plug-ins.

     

    -Noel

     
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  • Currently Being Moderated
    Aug 3, 2012 12:39 PM   in reply to ACRFREAK

    You were not rendering the area to 8 bit.

    You were applying a 16 bit adjustment to a 16 bit image though an 8 bit selection mask with a lot of feathering.  Yes, if you did a lot of those, you might see quantization.

    Without feathering, it wouldn't make a difference.  Without doing a lot of adjustments, it wouldn't make a visible difference.

     
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  • Currently Being Moderated
    Aug 3, 2012 1:41 PM   in reply to ACRFREAK

    Yes, but it's still an 8 bit selection even if it gets converted to a 16 bit mask (still has 8 bit quantization).

    Creating the mask in 16 bit is a better idea.

     
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  • Currently Being Moderated
    Aug 3, 2012 3:17 PM   in reply to ACRFREAK

    Create a layer mask, paint or manipulate the layer mask.

    You don't have to convert a selection to a mask.

     
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  • Noel Carboni
    23,469 posts
    Dec 23, 2006
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    Aug 3, 2012 3:57 PM   in reply to ACRFREAK

    Honestly, it's not worth worrying about, ACRFREAK.

     

    The likelihood of your manipulating partially selected pixels enough times and in ways that matter so as to make a visible image degradation is tiny.  I understand implicitly what's going on (having the benefit of being a software developer of Photoshop plug-ins) and I never worry about 8 bit selections vs. 16 bit masks.  Not that I don't use masks, but I use the selection tools as needed, and things just work out fine.

     

    -Noel

     
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  • Noel Carboni
    23,469 posts
    Dec 23, 2006
    Currently Being Moderated
    Aug 3, 2012 4:28 PM   in reply to ACRFREAK

    First let me say I am not trying to get you to lower standards or accept "good enough".  Lord knows, I don't.

     

    And I absolutely support your wanting to understand how things work in order to try to use the tools as well as possible.  Bravo for that!

     

    But it occurs to me that if you're using things like Content Aware Fill that replace pixels, the "damage" is may be coming from other places.

     

    Would you be willing to be more specific about a set of adjustments you've done leading to "damage" visible in prints?  Perhaps some workflow discussion is in order.

     

    -Noel

     
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  • Currently Being Moderated
    Aug 3, 2012 5:35 PM   in reply to ACRFREAK

    ACRFREAK wrote:

     

    "Creating the mask in 16 bit is a better idea."

     

    Sorry to sound dumb here, but in the above scenerio (color range and refine edge) is that posible?

     

    Side note, I don't work that way much any more.

     

    Yes, add an empty mask to the image layer, target the mask and click "Color Range..." in the mask's properties to access the color range "tool". The resulting mask will have finer gradation than when you do "Select > Color Range..." then convert the selection to a mask.

     

    Remember that the limited bit-depth of your monitor will result in an apparently similar banding in the 16-bit masks created both ways, but analysing the mask pixel values will reveal the finer gradation when an intermediate selection stage is avoided.

     
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