Noise reduction before or after sharpening

[Bill Carr]

I do all my post processing in LR.  I read somewhere recently that it is better to sharpen after NR so as not to sharpen the noise.  Is it true that sharpening after NR is preferable to sharpen then NR?  It seems that since LR processing is all non-destructive, it should make no difference.

It also seems that the results of LR processing is similar to doing each modification in PS, each on a separate layer, resulting in the ability to delete any step in the process.

Bottom line, is there a preferable sequence to the post processing process in LR?

Thanks!!

[langier]

If I'm not mistaken, LR sharpens during file output, most likely as the last step before saving.

My guess is that after you do all your adjustments, LR will take them all in the proper sequence after you tell it to render and output.

[Bill Carr]

I'm not outputting.  How can you say that it does not apply until saving.  There is no saving.  After making a change, the  hang is visible, which then leads to the next change. If it "will take them all in the proper sequence after you tell it to render and output", this implies it will not be the same as it was as I was making my adjustments.  This does not make sense to me.

I appreciate your input and desire to help, but I am not looking for a guess, I would like to hear from someone involved or intimately knowledgeable about the actual process going on behind the scenes.

[hjulenissen]

A large part of the motivation for making Lightroom in the first place seems to have been to make a "parametric" image editor. This means that Lightroom will keep track of what you decided to do to the image, but that those changes are applied only when Lightroom feels like it (rendering to display, rendering to print, rendering to file export). Proof of this is that they changed the debayer algorithm in 2010, with the option of re-applying it on older files, and the fact that the only file stored to disk is on the order of 100s of MB, not multiple GB as one would expect with something like Photoshop.

The inner workings of how Lightroom applies those edits is (to my knowledge) not known, and probably a well-guarded secret. It seems safe to assume that the Adobe people did a fair amount of thinking, testing and refinement before they decided on how it should work. Perhaps the sharpness is applied in several stages. Perhaps it is depending on the settings of other controls. As far as I am concerned, Adobe are at full liberty to implement the underlying processing in any fashion that allows me to make good-looking end-results using a set of controls that makes sense to me.

It makes little sense that the order of sharpness/NR _processing_ should be affected by the order in which I tweak the buttons. I expect the image pipeline to be fixed, and that every time I tweak a button, all subsequent parts of the processing will be re-applied.

-h

[John R Smith]

I do all my post processing in LR.  I read somewhere recently that it is better to sharpen after NR so as not to sharpen the noise.  Is it true that sharpening after NR is preferable to sharpen then NR?  It seems that since LR processing is all non-destructive, it should make no difference.

Bill

As Lightroom is a parametric editor, working on RAW data, it makes no difference to the end result in purely objective terms whatever sequence you choose to make the edits in. The alterations to the file are stored within the image catalogue or in the sidecar XMP file, and are only applied to an image as pixel data when you either export it or print it. However, the order does make a difference to your perception and editing efficiency when you are working on the image. That is why the editing tools are arranged in a (more or less) logical sequence from top to bottom of the screen. So, as sharpening will always increase the perceived amount and intensity of noise, it is best to apply the sharpening first (at least get it more or less in the ballpark) and then fix the noise. We can then go back and fine-tune the sharpening if we wish. Otherwise, you will fix the noise, do the sharpening, and then find that the noise looks a whole lot worse, and you have to do it all over again. Essentially, if you are doing a good job, sharpening and noise reduction go hand in hand and have to be applied in a mutually dependant fashion.

John

[KeithR]

I asked the late Bruce Frasier when to apply sharpening. His reply at that time was to do the noise reduction first then sharpen. He went on to comment that you didn't want to sharpen the noise. This was when most people were scanning film and working in Photoshop(and products such as Noise Ninja and PK Sharpener were just coming on the scene) and before Lightroom came to be. But when LR came out, it didn't matter because LR does it's processing in the order it needs to be done for optimal results at output. Remember, you're not working on pixels in LR, only meta data and nothing happens to the file until it's rendered out. What you are seeing on the screen when you edit in LR is there as a visual guide so that you can make decisions on what you what to do.

[Schewe]

Bottom line, is there a preferable sequence to the post processing process in LR?

No...the actual processing pipeline has nothing to do with the order that you set the parameters...you can alter them to your heart's desire up to the point where you process them for an export or a print. Then, of course, the settings are baked into the processed file.

[Bill Carr]

Thank you Jeff, Keith, John, and hj.  Your insights have created a brand new understanding for me of what LR is actually doing.  After all the Adobe forums and video tutorials, other articles, and LL video tutorials, I don't ever remember it being described quite this way.

Larry, your "guess" was correct.  I want to acknowledge you for being correct and for knowing more than I gave you credit for.  Thank you.  It didn't make sense to me because I didn't understand the concept of parametric editing.

I must have been thinking that it was actually re-rendering the image as I was making my mods.

I love lightroom.

[Robert Boire]

Hello,

Out of curiosity, could someone explain the difference between the sharpening that is performed in the Developer - and which can be controlled and visualized- and the optional sharpening that takes place during export - which cannot be visualized at all.

Thanks

R

[Schewe]

Out of curiosity, could someone explain the difference between the sharpening that is performed in the Developer - and which can be controlled and visualized- and the optional sharpening that takes place during export - which cannot be visualized at all.

The Detail panel is designed to do capture sharpening which is accomplished by visual determination. Different image sources and content require different sharpening parameters...output sharpening is a predetermined sharpening routine designed for the resolution and media and only offers 3 settings, Low, Standard and High. You don't want to do output sharpening by eye because you will inevitably miss-sharpen.

The LR output sharpening was based on PhotoKit Sharpeners routines and extensively tested by trial and error (with extensive tweaking along the way). It's the back part of the 3 phase sharpening workflow designed by Bruce Fraser; Capture sharpening upon input to regain the loss of sharpness in capture, Creative sharpening to locally enhance detail and Output sharpening to sharpen for the resolution and the media.

[CoyoteButtes]

Fascinating and informative thread. Thanks to Bill Carr and contributors.

Stan