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madeinlisboa
Participating Frequently
May 10, 2023
Question

Sharpening on cropped or uncropped images

  • May 10, 2023
  • 3 replies
  • 2553 views

I don't see an answer to this question anywhere. Is sharpening applied to the uncropped image or to the cropped one? If I edit a 24MP and crop it to 4MP, is the sharpening applied to the 24MP and then cropped or to the 4MP?

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    3 replies

    R
    Community Expert
    richardplondonCommunity Expert
    Community Expert
    May 10, 2023

    The sharpening controls inside Lightroom Classic work on pixels. For example, you can change the pixel radius over which sharpening is determined. Amd the recommendation is to work at 1:1 zoom (or failing that, to use the small 1:1 preview window inside the Detail panel) so that you can see what is happening with the pixels and the picture content in its own local terms.

     

    How large or small a part this local area of pixels plays within the overall image, including how prominently the sharpening of the picture details will show, is a separate matter. But that is no different than how prominently the pixels themselves will show, carrying with them (as they zoom larger in effect, when you crop smaller) any lens softness or diffraction or demosaicing issues which this same sharpening is attempting to mitigate. 

     

    There's another aspect though: when exporting, output sharpening can be selected off / low / medium / high. For this purpose, if you crop down to a 4MP selection and then choose export settings amounting to 4MP, your export is more or less happening at original pixel resolution. But if you don't crop down from 24MP, and your export settings amount to 4MP, meeting that requires considerable downsizing, Output sharpening will 'understand' the practical difference between different export scenarios, and tries to allow for that towards a similar looking result regardless (when considered in terms of the final output pixels). Loosely: those will look the same amount sharper than they would otherwise have been, no matter whether you are exporting FROM 4MP or 24MP. Naturally that will also look different depending whether you are exporting TO 4MP ro 24MP.

     

    The best way to evaluate all this, and there is a lot of sheer preference involved, is to simply try it.

    TheDigitalDog
    TheDigitalDog
    Inspiring
    May 10, 2023

    Capture and output sharpening (limited) are based on this; the product mentioned (in which I played a small role <g>) are connected at the hip. The concept and some of the sharpening routines were licensed by Adobe from Pixel Genius:

    http://creativepro.com/out-of-gamut-thoughts-a-sharpening-workflow/ 

    Author “Color Management for Photographers" &amp; "Photoshop CC Color Management/pluralsight"
    Conrad_C
    Community Expert
    Conrad_CCommunity Expert
    Community Expert
    May 10, 2023

    I guess you could call it Schrodinger's Image Editor, in that any edits, including sharpening and cropping, are simultaneously there (as parametric edits you can preview) and also not there (not affecting the original); the edits are permanently applied only to an exported copy.

     

    I just tried it, so it’s easy to confirm. I cropped an image, applied enough sharpening to be obvious, then open up the crop, and the sharpening is already in the area that was formerly cropped out.

     

    Probably a good general way to think about it is:

    If a non-masked edit is applied to a cropped image, it applies to the entire image, regardless of cropping. Because even the crop is permanently applied only to an exported copy.

     

    So if we’re talking spatially, only a mask will persistently restrict the area of an adjustment.

     

    The only exception I can think of is Post-Crop Vignetting, which by definition always stays within the crop area.

      M
      madeinlisboaAuthor
      Participating Frequently
      May 10, 2023

      I'm definitely not able to explain properly. I attached an uncropped photo and a cropped one. Both were subjected to a sharpening amount of 85 in Lightroom and exported. First thing I noticed is that I can't align them in Photoshop which means that the images are not identical, although are from the same photo. I did my best to align both and then cropped the full res based on the LR crop. The size of both exported TIF (the Lightroom cropped and the full res cropped in Photoshop) was almost the same (the difference was propbably due to the fact that I couldn't align them), which means that Lightroom crops AFTER sharpening. I guess this also applies to noise reduction.

      Conrad_C
      Community Expert
      Conrad_CCommunity Expert
      Community Expert
      May 11, 2023

      I understand that the two images you posted are JPEG format and not the original TIFF format, but even then, after aligning them precisely in Photoshop using the common Difference mode technique, there seems to be no difference between the cropped and uncropped versions. Neither image was resized or resampled, simply layered 1:1. This is what is shown below:

      1. The two images are added to the same Photoshop document, not yet aligned.

      2. The cropped image layer is set to the Difference blending mode, because this mode reveals any differences between the selected layer and the layers behind it. Black pixels indicate no differences between the layers.

      3. The cropped image is repositioned, to manually align it with the uncropped image. At one position, the cropped image appears completely black. This indicates two things: There are no differences between the images, and because there is no difference, they are perfectly aligned. This is why many people use the Difference mode to manually align layers, especially when automatic alignment fails.

       

      (The image colors may look posterized in the animation. This posterization is not in the original animated GIF file; the forum software seems to recompress this format.)

       

       

      No difference is what I would have suspected, because of how sharpening works (hopefully this is correct); I think none of the following Lightroom Sharpening options are related to or affected by changing pixel dimensions such as by cropping:

      • Amount is a sort of amplitude which I think is not spatial, so the same amount should produce the same result regardless of pixel dimensions.
      • Radius is related to nearby pixels, so if neither version of the image was resampled, Radius should have the same result before and after cropping. (However, the identical result of the same Radius value can be perceived to be different if the cropped version is reproduced at a different pixel density (ppi) than the uncropped version.
      • Detail is related to detail frequency, so again its result should be the same for a cropped and uncropped version.
      • Masking is, I think, similar to Radius in that it’s going to be about nearby pixels and not affected if the overall pixel dimensions change.

       

      And the reason others asked you if sharpening was applied in the Export dialog box is because by its nature, output sharpening can be affected by pixel dimensions and output targeting, for example if both versions were exported with output sharpening set for printing.

      TheDigitalDog
      TheDigitalDog
      Inspiring
      May 10, 2023

      The crop, like all edits, is totally nondestructive. All the edits are just instructions for processing upon Export (or Open in Photoshop). If and when you render the raw, it is what it was asked to be: cropped (maybe to 4MP) and sharpened for that crop. The original is untouched. 

      Author “Color Management for Photographers" &amp; "Photoshop CC Color Management/pluralsight"
      M
      madeinlisboaAuthor
      Participating Frequently
      May 10, 2023

      Thanks, but it is not what I asked. I know it is nondestructive. What I asked is if the sharpening is applied to the 24mp image before being cropped or to the 4MP crop.

      eg. Sharpening amount of 50 to the 24mp image and to the 4mp crop. Would the 24mp image cropped later to 4mp in photoshop be the same as the 4mp crop in Lightroom?

      TheDigitalDog
      TheDigitalDog
      Inspiring
      May 10, 2023
      quote

      Thanks, but it is not what I asked. I know it is nondestructive. What I asked is if the sharpening is applied to the 24mp image before being cropped or to the 4MP crop.

      eg. Sharpening amount of 50 to the 24mp image and to the 4mp crop. Would the 24mp image cropped later to 4mp in photoshop be the same as the 4mp crop in Lightroom?


      By @madeinlisboa

       

      I explained precisely how parametric editing would work in your example. 

      Sharpening isn't applied to anything that isn't rendered. Not that it would matter. 

      The Adobe Camera Raw engine makes the edits in what Adobe feels is the best processing order, NOT user order. 

      Author “Color Management for Photographers" &amp; "Photoshop CC Color Management/pluralsight"
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