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AaronShep
Currently Being Moderated

Nitpicks with "Bicubic Automatic"

Apr 3, 2012 8:48 PM

I'm seeing two problems with the Bicubic Automatic setting in the Image Size dialog.

 

1. On reduction, this produces oversharpening. Skin particularly comes out awful. Or maybe it's just that the sharpening is being applied equally throughout the image, instead of intelligently as with the Smart Sharpen command.

 

2. If I change this setting to something else, it reverts back to Bicubic Automatic the next time I enter the dialogue. In the past, this setting has always been sticky. It's very annoying to have to be careful to change it each time.

 

To sum up, you've made it hard to change from a default setting that is not working well!

 

Aaron

 
Replies
  • Currently Being Moderated
    Apr 3, 2012 11:43 PM   in reply to AaronShep

    Check your Preferences setting for the Image Interpolation field in Preferences > General > Image Interpolation.

     

    CS6_Prefs_Imge_interpolationCROP.jpg

     
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  • Noel Carboni
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    Dec 23, 2006
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    Apr 4, 2012 12:39 PM   in reply to AaronShep

    I've changed back to Bicubic myself.  I could never see the reasons for using those others.

     

    What "part of it" is left to be solved?

     

    -Noel

     
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  • Noel Carboni
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    Dec 23, 2006
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    Apr 4, 2012 2:10 PM   in reply to AaronShep

    ''Bicubic Sharper'' just does that.  Adobe's ideas of ''best for downsampling'' and mine just differ.  Have you used 'Bicubic Sharper'' before?

     

    ''Bicubic'' is what Photoshop has always defaulted to up to now.

     

    Make your default ''Bicubic Smoother'' to completely avoid any sharpening (which by the way there seems to be just a little of in just plain ''Bicubic'' as well). 

     

    -Noel

     
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  • Noel Carboni
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    Apr 4, 2012 3:08 PM   in reply to AaronShep

    I don't think it's making any choices, except to use Bicubic Sharper for downsampling and Bicubic Smoother for upsampling.

     

    I'm thinking of doing some comparisons...  I'll see if I can find a good image for showing the differences.

     

    -Noel

     
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  • Currently Being Moderated
    Apr 4, 2012 4:27 PM   in reply to Noel Carboni

    Noel Carboni wrote:

     

    I don't think it's making any choices, except to use Bicubic Sharper for downsampling and Bicubic Smoother for upsampling…

     

    Precisely!

     
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  • Noel Carboni
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    Apr 4, 2012 4:39 PM   in reply to Noel Carboni

    Okay, I did some comparisons of the various forms of downsampling. What I did was find a representative image with some good contrasts, then downsample to 25% using the various methods in Photoshop CS5 and CS6, then re-upsample to original size using Nearest Neighbor, so we can clearly see the pixels. Here are the results:

     

    Photoshop CS5:

     

    BicubicSharper.jpg

     

    Bicubic.jpg

     

    BicubicSmoother.jpg

     

     

    Photoshop CS6:

     

    BicubicAuto.jpg

     

    BicubicSharper.jpg

     

    Bicubic.jpg

     

    BicubicSmoother.jpg

     

    Based on these, I'd say there's actually some USM sharpening in Bicubic Smoother as well, more than just plain Bicubic!

     

    Seems pretty obvious to me that just plain Bicubic is still the best, but to each his own!

     

    -Noel

     
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  • Currently Being Moderated
    Apr 4, 2012 5:11 PM   in reply to Noel Carboni

    Noel Carboni wrote:

    Based on these, I'd say there's actually some USM sharpening in Bicubic Smoother as well, more than just plain Bicubic!

     

    Seems pretty obvious to me that just plain Bicubic is still the best, but to each his own!

     

     

    Pretty sure it ain't USM...but there IS a sharpening component to BiCubic Sharper (as the name implies). I actually think the sharpening is a bit more advanced than USM but I couldn't tell you exactly what algorithm it's using but I think it's a hybrid–Chis Cox would know…

     

    What I'm not sure of is whether or not CS6's Auto is picking up on LR's Adaptive Bicubic. In LR there's an interpolation between Bicubic Smoother/Sharer based on the amount that the resampling is doing. Close to the original size it's pretty much 100% regular Bicubic, the more you enlarge or reduce the more it moves tower Smoother (for up) and Sharper (for down). Again Chis would have to fill in the blanks…

     

    I "think" the CS6 Auto is simply picking and using Smoother for upsample, Sharper for down sample and Bicubic if not changing the overall pixel dimensions. But again, I don't know for an absolute fact…this is a "Chris question".

     

    :~)

     

    In any event Image Size always follows the default resampling set in the PS prefs...it allows you override in the Dlog but is not sticky.

     
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  • Currently Being Moderated
    Apr 4, 2012 6:15 PM   in reply to Jeff Schewe

    I find that the results from using CS6 Auto is a bit too "crunchy" when downsampling to perhaps only 25% of the original size (as you might do for Web display purposes).

     

    Also there is usually some considerable darkening/clogging of the mid-tones when you downsample and it would be great if a correction for that could be built-in to the resampling algorithm.

     
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  • Currently Being Moderated
    Apr 4, 2012 7:28 PM   in reply to Jeff Schewe

    Bicubic Smoother and Bicubic Sharper already taper off as you near 100% scaling, and ramp up to a constant amount around 400% or 25%.

    It's not the same math as LR, but similar in concept.

     

    And yes, the automatic mode is using smoother for upsampling and sharper for downsampling.

     
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  • Currently Being Moderated
    Apr 4, 2012 9:21 PM   in reply to AaronShep

    Sharper == reducing in size, because reduction leads to a lot of blurring and loss of detail and needs some sharpening to make it look right.

    Smoother == enlarging in size, because enlarging needs that extra smoothing to keep edges from showing artifacts, and a little sharpening to keep edges crisp.

     

    Using them backward really won't help you (and would only look even halfway decent on *perfect* test images).

     

    The names are quite correct, even if the actual parameters aren't as one dimensional as you assumed.

     
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  • Currently Being Moderated
    Apr 4, 2012 10:16 PM   in reply to Chris Cox

    Chris Cox wrote:

     

    It's not the same math as LR, but similar in concept.

     

    Thanks for the confirmation...

     

    As far as Sharper/Smoother, these variants were created specifically to address the problems with resampling up or down. Yes, Sharper has a sharpening component, but it's not really useful for upsampling as Bicubic Sharper will introduce sharpening artifacts that preclude other post upsampling sharpening–which must be done separately from the upsampling to get optimal results. Yes, on the "surface' some might see useful results with upsampling but it's not as good as applying post upsample image sharpening. This isn't hard to prove...see this article The Art of the Up-Res from Digital Photo Pro magazine (and yes, I wrote that article a while ago, but it still is applicable now)

     
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  • Currently Being Moderated
    Apr 5, 2012 9:57 AM   in reply to AaronShep

    Most bicubic kernels have some sharpening, otherwise they would not give good results.

    As for the sharpening - it usually looks good at the final size (not re-enlarged).

     
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  • Noel Carboni
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    Apr 5, 2012 4:20 PM   in reply to Chris Cox

    I for one prefer the least sharpening possible from the resampling algorithm so that I can apply much better sharpening algorithms myself.

     

    -Noel

     
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  • Currently Being Moderated
    Apr 5, 2012 8:12 PM   in reply to AaronShep

    I agree with Noel.

     

    Unfortunately both recommended down-sampling methods in CS6 (Bicubic Sharper and the new Auto) do over-sharpen for most kinds of subject matter.

     

    It really would be better if the degree of sharpening in both algorithms could be toned down a bit so that the User can then add further Output Sharpening or local sharpening at their own discretion.

     
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  • Currently Being Moderated
    Apr 8, 2012 7:52 AM   in reply to CameraAnn

    CameraAnn wrote:

     

    Unfortunately both recommended down-sampling methods in CS6 (Bicubic Sharper and the new Auto) do over-sharpen for most kinds of subject matter.

    Yes, that's my impression, too. I do understand that digital images need some re-sharpening after (or while) downsizing ... but Photoshop's Bicubic Sharper now grossly exaggerates the sharpening effect in CS6. Strange I never noticed this in CS5 or earlier.

     
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  • Currently Being Moderated
    Apr 8, 2012 8:35 AM   in reply to 01af

    One thing I did not realize (noticed this when testing out Bicubic Automatic) is if you use one interpolation method when resizing a Smart Object. Then return to another. Then Edit Contents of that SO, Photoshop will re-render the scaled SO with the current interpolation method, even if you did not additional scaling to the SO.

     
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  • Noel Carboni
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    Dec 23, 2006
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    Apr 8, 2012 8:56 AM   in reply to charles badland

    I suppose that makes sense, Charles, insofar as it has to resample the changed SO data to make it the proper size. 

     

    But what you're really saying is that the interpolation method is not stored in the file itself; it uses the ambient resampling, and I can see how that could be unexpected with a file edited on multiple different machines (or at different times) with different settings.

     

    -Noel

     
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  • Currently Being Moderated
    Apr 8, 2012 9:02 AM   in reply to Noel Carboni

    Yes, that is what I thought too.

    It was unexpected, but probably makes sense that any edit to SO contents would have to be re-rendered and would use the currently chosen interpolation.

     
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