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Feedback wanted regarding resizing process for forum images.

Discussion in 'Help and Feedback' started by Amin Sabet, Dec 3, 2018.

  1. Quadratic + USM

    0 vote(s)
    0.0%
  2. Lanczos

    66.7%
  3. Lanczos + USM

    33.3%
  1. Amin Sabet

    Amin Sabet Administrator

    Aug 6, 2011
    As many of you know, our forum software automatically resizes large images to a maximum size of 1600px. We use Imagick to do that, and I've edited the core forum software so that it doesn't strip EXIF information, which it otherwise does by default.

    I'm working on making the same edits for XenForo 2 in advance of a big upcoming site upgrade to that software. There are a number of Imagick resize filters which can be used, and I'd like to get your feedback about which of these three you think give the best results.

    Here are the original files: original samples - Google Drive

    In each of the following three sets, the first one is Quadratic + USM, second is Lanczos, third is Lanczos + USM:

    1a-jpg.jpg
    Subscribe to see EXIF info for this image (if available)

    1b-jpg.jpg
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    1c-jpg.jpg
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    2a-jpg.jpg
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    2b-jpg.jpg
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    2c-jpg.jpg
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    3a-jpg.jpg
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    3b-jpg.jpg
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    3c-jpg.jpg
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  2. Amin Sabet

    Amin Sabet Administrator

    Aug 6, 2011
    Just to clarify, if you resize to 1600px or less before uploading, then you fully control the sharpening. The forum software doesn't do any resizing or sharpening in that case. This setting only affects the output when you upload at larger than 1600px and let the forum software do the resizing.
     
  3. addieleman

    addieleman Passionate amateur Subscribing Member

    Nov 13, 2012
    Netherlands
    Ad Dieleman
    Lo and behold, I can even see a difference. I prefer the second one, the Lanczos filtering, as a good middle ground between #1 and #3. That said, I always resize my pics to 1600px before uploading so for me it's a moot point.
     
  4. Kiwi Paul

    Kiwi Paul TalkEmount All-Pro Subscribing Member

    Feb 14, 2016
    Aberdeen, Scotland
    Paul
    TBH it's hard to see much difference but I picked Lanczos +USM.
     
    • Agree Agree x 1
  5. Tipton

    Tipton TalkEmount Top Veteran

    558
    Jan 30, 2016
    Rae Leggett
    I agree with Ad, Lanczos looks better to me. But it's not enough of a difference to be a big deal.
     
    • Agree Agree x 2
  6. Amin Sabet

    Amin Sabet Administrator

    Aug 6, 2011
    The USM I have been using is unsharpMaskImage(0 , 0.5 , 1 , 0.05) where the numbers in parentheses refer to radius, sigma, amount, and threshold respectively. Here is a version of Lanczos with unsharpMaskImage(0 , 0.5 , 0.5 , 0.05), which is half the amount of USM as the third version in the OP:

    15468525846_f26c522812_o.jpg
    Subscribe to see EXIF info for this image (if available)
    22074165246_cdf037d31d_o.jpg
    Subscribe to see EXIF info for this image (if available)
    34504091606_60b8eccaf7_o.jpg
    Subscribe to see EXIF info for this image (if available)
     
  7. Amin Sabet

    Amin Sabet Administrator

    Aug 6, 2011
    For sake of comparison, here is what automatic resizing by Flickr produces:

    **wrong images posted by accident. now removed. **
     
    Last edited: Dec 3, 2018
  8. Amin Sabet

    Amin Sabet Administrator

    Aug 6, 2011
    Wow, it looks like Flickr doesn't strip EXIF in the resized images any more. That's great!

    My mistake, Flickr still strips EXIF.
     
    Last edited: Dec 3, 2018
  9. Amin Sabet

    Amin Sabet Administrator

    Aug 6, 2011
    To my eye, Flickr results look just like Lanczos + USM.

    I posted the wrong files for Flickr.
     
    Last edited: Dec 3, 2018
    • Agree Agree x 1
  10. AlwaysOnAuto

    AlwaysOnAuto TalkEmount Hall of Famer

    Feb 17, 2015
    My tired old eyes can't see any decernable difference in them Amin.
    Guess it's time to get new glasses.

    Thanks for the efforts you put into making this a great place to hang out.
     
    • Agree Agree x 2
    • Appreciate Appreciate x 1
  11. adwb

    adwb TalkEmount Regular

    159
    Sep 30, 2015
    Bristol UK
    Alistair
    well I voted for Lanczos, BUT on my little 27" Viewsonics monitors I have to admit I'm not sure why, it just looks better but I can't explain why.
     
    • Agree Agree x 1
    • Appreciate Appreciate x 1
  12. WoodWorks

    WoodWorks Super Moderator Subscribing Member

    Dec 12, 2012
    Ashland, OR, USA
    David
    Sorry, Amin. There may be some difference between them. But I sure can’t see it. If pressed, I’d vote for whichever of them loads fastest.
     
    • Appreciate Appreciate x 1
  13. bdbits

    bdbits TalkEmount All-Pro

    Sep 10, 2015
    Bob
    I also think Lanczos is a bit better, but I am more ambivalent on the USM comparisons. One thought is what if any impact it has on CPU, if you have to pay for that wherever you are hosting.

    I presume this only happens on upload though, so it would not matter for viewing.
     
  14. Amin Sabet

    Amin Sabet Administrator

    Aug 6, 2011
    Our server load is pretty low just about all the time. The USM doesn't seem to have much impact.
     
  15. christilou

    christilou TalkEmount All-Pro

    Nov 26, 2012
    Surrey, UK
    Christina
    I always export my pics large for printing and I can't be bothered to keep resizing to be honest so I'm for anything that works for you really :) 
     
  16. WNG

    WNG TalkEmount Hall of Famer

    Aug 12, 2014
    Arrid Zone-A, USA
    Will
    I preferred #2 and then #3. #2 looked best on my 27" monitor as well.
    Given the downsizing, nearly all large images will appear sharper especially at 1600px, and I think USM isn't required and become either indiscernible or ruins the image by over aggressive sharpening an over-sharpened original.
     
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