rob_cole_2221866's profile

4.5K Messages

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76.3K Points

Wed, Apr 6, 2011 9:03 AM

9

Lightroom/Camera Raw: Improve Sharpen Masking

I love everything about the new sharpener, except the masking artifacts.

There is a tell-tale artifact of the masking that I call "sparkling", which I've grown to dislike so much I rarely use the masking anymore.

Its sort-of reminiscent of the masking halo artifact left by brushing - the sharpening spills too much out of the edgy area and into the smooth areas, leaving a sharpening sparkle around the edges of things.

Its unfortunate, since the concept of masking is great, and the UI for it is awesome (alt key to see where it will apply).

Some way to "pull in the sharpening effect" around the edges, so to speak, (or something like that), to eliminate sparkling would by greatly appreciated.

PS - Reducing detail helps, but then of course you lose detail in sharpened areas...

Rob

Responses

948 Messages

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13.9K Points

10 y ago

I have masking set up in my defaults, and I've never noticed any "sparkling". Can you post some examples of similarly-sharp images both with the sparkle and without it? The "without" will obviously have to be sharpened using another method.

170 Messages

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5.3K Points

10 y ago

I don't use auto masking any more for the exact same reason. It simply doesn't work well enough.

4.5K Messages

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76.3K Points

10 y ago

Settings chosen to exagerate the problem, so it looks pretty bad, but here's one:



Note: Crustiness around the edges I call sparkling.

Sharpness: 70
Radius: 1.5
Detail: 80
Masking: 80

Lum. NR: 17

4.5K Messages

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76.3K Points

10 y ago

And here's one with same sharpen settings, but detail turned way down, and masking turned all the way off. I also reduced luminance noise reduction some.



Note: This was not a sharp picture to begin with, and was shot with a D300 @ISO3200.

Note: less crusty around the edge junctions.

Sharpness: 70
Radius: 1.5
Detail: 10
Masking: 0

Lum. NR: 9

4.5K Messages

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76.3K Points

10 y ago

Note: I realize this is not a "fair" comparison.

As I said before: one can reduce the sparkle by reducing detail, and the extra Lum. NR in the above shot tends to oversmooth the areas without the sparkle, which was the purpose. The point of this exercise was to demonstrate the phenomemon to which I am refering, which I think this example accomplishes.

PS - A good way to compare these two shots is to download the images, then switch back and forth..

R

4.5K Messages

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76.3K Points

10 y ago

This phenomenon seems to be noticed by and bothers some individuals, but not others. If the shot has very little noise, or very little sharpening, then its barely noticeable. It becomes more glaring as noise and sharpening increase. The reason I chose a noisy unsharp photo was to make it obvious. Its not tied to the lens. It is tied to the masking. It could be remedied by an adjustment to the masking algorithm.

4.5K Messages

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76.3K Points

10 y ago

DxO:

4.5K Messages

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76.3K Points

10 y ago

Surprised me how good this photo turned out in DxO. I purposely tried to process it to look the Lightroom version.

4.5K Messages

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76.3K Points

10 y ago

NX2:

Note: I did not spend as much time working the NX2 image as I did the others, but should still give an idea...

513 Messages

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11.1K Points

10 y ago

Rob, I don't think you should change the "Detail" settings between comparisons.

I wonder whether the crustiness you are seeing isn't just noisy sharpening halos, i.e., has nothing to do with the masking. In this case masking would only highlight the noisy sharpening halos because the rest looks smoother, but wouldn't introduce them.

I tried to replicate your problem and in my experiments masking never introduced crustiness but only made it more visible. I only tried two photos so I'm not saying you don't have a point, but it might be worth posting a comparison where only the masking value is changed and everything else is left constant.

4.5K Messages

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76.3K Points

10 y ago

There's no question where it comes from: The mask encompasses edgy areas with a fading from edgy area to smooth area. That works out nicely in broad areas that have gradual transitions between edgy and smooth, but across hard edges the noise is being sharpened in areas that should be smooth bokeh. You can tell by looking at the mask that the algorithm has two rankings: edgy and smoothy, and the mask value just sets a threshold. It needs to be modified for hard edge to smooth bokeh transition detection and not spill the sharpening into the bokeh. Or something like that. I mean, other software does not have the same artifacts (see DxO & Nx2 above). Sometimes they have other artifacts instead, but my point still stands. I've commiserated about this in private with several other people who can't understand why this isn't noticed by every critical eye, and bothers all of them. I've brought this up a few times before in the forum, and always with the same generally cool reception, except for a couple of people saying "Amen". The purpose of the above examples was to illustrate the phenomena, not to compare different methods of sharpening. You can see from the top picture, that the detail sharpening extends too far beyond the edges of things. I mean maybe my under-the-hood speculation and/or proposed solution is laughable to those who understand the inner workings, but the phenomenon is offensive enough to me and some others that we simply dont use it (except as a quick solution for photos we dont care too much about...). If we are in a small enough minority that Adobe wont fix it, then so be it, but I hope something gets done about it.

4.5K Messages

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76.3K Points

10 y ago

When I do use the sharpen masking, I generally set Detail on zero. Lightroom's PV2010 raw conversion algorithm is inherently very detailed, and as you've said: its hard to tell the difference between true detail and noise detail in the sharpening of it. I have presets based on ISO that assign a default detail between 25 (for ISO100), 20 (for ISO-200), ..., to zero for ISO3200... Its true that I never noticed this phenomenon for the first year I used Lightroom, but now I'm very sensitive to it. Anyway, yes: best to recover detail in high-ISO shots using the NR detail sliders if possible before resorting to sharpening detail.

Summary: masking is not creating the artifacts. the artifacts come from sharpening detail all around edge areas, and the sharpening, unfortunately extends too far into the smooth regions for my taste, when using the sharpen mask.

PS - Even at detail = 0, there is considerable "detail" sharpening...

I mean, maybe the solution is not in the masking, but in the sharpener itself - something that can separate more linear edges and leave the "sand" alone - I dunno. I've never written any image processing software in my life...

4.5K Messages

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76.3K Points

10 y ago

Lightroom again:

Sharpening:
Amount 70
Radius 1.5
Detail: 10
Masking 65

Lum. NR: 17

i.e. same settings as original post, except detail left low, and masking reduced.

Intended for comparison purposes (as opposed to exaggerating the phenomenon like the first sample).

These are more reasonable settings, and the sparkling phenomenon is far subtler, but still existent.

I think a simple change to reduce detail sharpening in transition zone between masked and unmasked areas would do it. So full detail is rendered only in areas not near boundary between masked and unmasked regions, and zero detail is rendered in transition area bordering on masked region - blended in between. As it stands, full detail is being sharpened if its unmasked, and zero sharpening is being applied if its masked, and there is no graduation, no blending in the transition zone, making for an abrupt transition between masked and unmasked which is why the sparkling.

Note: this phenomenon also occurs in the bokeh - spurious detail sparkling occurs due to edge threshold being exceeded a smidge - little patches of unmasked areas with sharpened detail dance with the adjacent completely masked & smooth bokeh. The above mentioned change would fix this too, since detail would be repressed due to proximity to the adjacent masked areas.

175 Messages

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3.8K Points

10 y ago

Rob, LR Detail is the devil. I rarely go above 10. In fact, I rarely go above zero.

Push it up to max just to look at the grain structure it creates and tell me if it create shapes you want applied to to your pixels at any opacity.

Amount, radius, masking = pleasing.

Detail = trouble.

I like that image, btw.

Have you tried Detail and NR both off?

4.5K Messages

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76.3K Points

10 y ago

Hey Scott,

Yeah, I hear you about the detail.

For this image, at such high ISO, if I were sharpening it soley in Lightroom, I would definitely turn detail off completely, and keep NR low - begrudgingly (NR does good things everywhere except the bee's fur, which if more than a tiny bit essentially ruins it). And then just hand sharpen the bee. In fact, here it is:

Global Sharpening
Amount: 0
Radius 1.3
Detail: 0
Masking: 0

Lum. NR: 8

Not as sharp as some of the others, and still has a fair amount of grain in the bokeh, but has a natural look without artifacts, IMO.

Final Thoughts:
--------------------
I usually sharpen *some* detail if its a low ISO shot (such that the detail is real, and not just sharpened noise), and/or the picture really warrants it: textured surfaces like rock... but, if I decide to cut corners and use the masking, I almost always crank the detail all the way down to zero, to lessen the sparkling.