Adobe Camera Raw sharpen?

Started Dec 2, 2011 | Discussions thread
Jeff Schewe Regular Member • Posts: 430
Re: Adobe Camera Raw sharpen?

Bruce Oudekerk wrote:

Thus when we 'sharpen' in ACR it is, by its nature, performed early in the image creation process and not at an appropriate point near the end. That’s one of the reasons I don't sharpen in ACR but that appears not be a valid criticism of LR.

Oh, you are sharpening in ACR/LR and similar to USM depending on the settings. If you increase the Detail slider you move more towards a deconvolution kernel sharpening.

As for the processing pipeline, it's wrong to think of the pipeline as "linear", it's not. Some stuff such as demosiacing and camera colr adjustment is done early in the pipeline. But depending on which tools you use, some stuff is done on luminance data only (such as sharpening) and some on HSL data (the HSL sliders). The actual processing pipeline is very complicated and exotic. But believe me when I tell you the sharpening is done at the optimal stage for sharpening to be done as determined by Thomas Knoll, who knows a thing or two about optimal anything relating to image processing.

You'll note that the sharpening and noise reduction is in the same panel and there's a reason for that–you need to optimize the settings for BOTH sharpening and noise reduction in ACR/LR. Sharpening and noise reduction are the opposite side of the same coin. If you don't use both sharpening and noise reduction you are leaving potential image quality on the table.

The sharpening in ACR/LR (note they both use the same algorithms and pipeline) are based on the thoughts of the late Bruce Fraser regarding a sharpening workflow. The initial round of sharpening if considered "capture sharpening" needed to restore the sharpness lost in the digital capture being turned into pixels (particularly needed if you camera uses and aliasing filter such as most DSLY cameras). The ideal approach is to set the sharpening and noise reduction to look "good" in ACR/LR. Creative sharpening is done usually on a local basis to emphasize certain areas. The final sharpening step is output sharpening which is done based on the final output resolution and the media type and printer type. You can read more about Bruce's ideas here

Just so you know, I worked with Adobe on developing the capture sharpening in ACR/LR. I took over a contract Adobe had with Bruce to do the consulting. Unfortunately Bruce passed away before it was incorporated into ACR/LR. I was also involved with the incorporation of PhotoKit Sharpener's output sharpening into Lightroom's Print module and also in ACR's batch save.

ACR/LR already cover the capture and output sharpening very, very well. The weak point in the sharpening workflow is really the creative sharpening. Hopefully more work will be done in that area.

I'll end by saying that if you don't take advantage of the optimized detail you can get from ACR/LR's sharpening and noise reduction, then you'll be making you life harder in Photoshop and prolly give up some potential image quality. While the luminance noise reduction is zero by default, any image can benefit from some luminance noise reduction, even low ISO well exposed images. Adding the right amount of luminance noise reduction work to allows you to optimize the sharpening (and visa versa).

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Jeff Schewe

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