Selective Sharpening Question

[Nick Davison]

I have probably been thinking too much lately and confused myself but I have noticed that in certain images where important details look a bit soft on the raw image, it is suggested that selective sharpening of the area can be applied before the image is saved as a master file.

Would this area become over sharpened when general sharpening is applied to the master file for print or web use or am I missing something? Are there any recommendations as to the amount of sharpening that can be safely applied selectively before sharpening the image for output use if oversharpening can occur?

Thank you in advance for your help,

Nick

[Daniel Cadieux]

Nick, I only selectively sharpen for web or print. I don't sharpen any master file except for minimal capture sharpening...all other sharpening should come as the last step, but not on the master file. I use Lightroom for RAW files, and don't recall being able to selectively sharpen a RAW file? I'm sure others will chime in if you can do so with other RAW software.

[Chris Starbuck]

Nick,
More on single-pass vs. multi-pass sharpening below, but I'll address your question about selective sharpening with an alternate (single-pass) approach first.

What I typically do when one area of an image needs different sharpening than other areas is to apply a layer mask to just that area, and sharpen for just that area. Then I'll apply a different layer mask (on a separate layer) which excludes that first area when sharpening other parts of the image. So if I need to sharpen different parts of an image differently I'll create a separate sharpening layer for each area. Actually, I hardly ever sharpen globally - I nearly always use layer masks - because applying the same sharpening to the whole image usually ends up enhancing noise or introducing other artifacts in OOF areas of the image. And I ALWAYS sharpen on a separate layer (merged, with all preceeding adjustments), set to Luminosity blending mode. A trick I learned from Bruce Fraser (more below) is to set the layer's opacity to 70% before sharpening, so that afterward you can not only decrease the effect (by reducing opacity) but also increase the effect (by increasing opacity).

A really neat feature in Photoshop CS4 (I skipped CS3 so don't know if it was added then) is the ability to turn a layer into a Smart Object before applying a filter (select Filter > Convert for Smart Filters). This causes PS to save an unmodified version of that layer, and apply the filter(s) to the current view. So when you've applied a filter (or a bunch of filters in succession) to that layer, you can come back at any future time and change the filter's settings! True non-destructive filters at last! This also means that I only have to create my sharpening layer masks once (in my master file), and can still do my one-time-only sharpening at the final output size (by resizing my master and sharpening before flattening). BTW, I strongly advocate NEVER flattening a master file; if you need to flatten, save a copy.

Now, about single vs. multi-pass sharpening. Conventional wisdom is to sharpen only once, and that as the very last step in the workflow, at the final image size. (And that's what I do most of the time.) However, the late Bruce Fraser, widely recognized as the industry guru on sharpening, was a strong advocate of multi-pass sharpening, and had sound technical reasons for doing so. He sharpened in specific ways, for specific purposes, at 3 points in his workflow. Done properly, multi-pass sharpening does not produce an over-sharpened result. Your questions are really about this, and I'll have to just point you to Fraser's book, "Real World Image Sharpening with Adobe Photoshop CS2". It's well worth reading, even if you don't adopt his entire workflow. It will give you a good understanding of what affects apparent sharpness in a digital image, and how to sharpen optimally. He has a terrific (if somewhat complex) technique for creating an edge-based mask for sharpening, which restricts sharpening to just those areas where it will do some good without enhancing noise or creating other artifacts. He also explains step-by-step how to turn the process into a Photoshop action, which makes using it a single click process.

I hope some of this is actually helpful.:)

[Nick Davison]

Hi Daniel/Chris

Thank you both for your help and information that you posted.

Daniel - sorry I haven't made myself very clear. By master file I mean the TIFF created from conversion of the raw file and being further enhanced Photoshop.

Chris - thanks for the Bruce Fraser information, will follow that up

I think I got confused after reading Birds as Art 2 CD by Arthur. He mentions selective sharpening on Master files if needed and it then appears he his still applying sharpening to the overall image but on re-reading the text I'm think that I have misinterpreted the point being made.

Once again, thanks for your help

Nick

[Robert O'Toole]

I have probably been thinking too much lately and confused myself but I have noticed that in certain images where important details look a bit soft on the raw image, it is suggested that selective sharpening of the area can be applied before the image is saved as a master file.


The most important thing to remember is that your "RAW image" is probably just an embedded JPEG and not a RAW file at all. Be sure you are viewing a output file and not a JPEG preview image.

Default ACR and LR settings will do apply gobal sharpening when you convert a RAW file. This is generally acknowledged as a counter measure for the effects of the camera's low pass filter.

All other types of sharpening should be based on the output requirements, such as email or a 20x30 print.

Normally I only sharpen selectively.

Robert

[Nancy A Elwood]

Nick are you using Canon or Nikon? I use Nikon and PP in NX2. When I PP I sharpen a bit the overal image, then use high pass sharpening selectively to the areas I feel are the most important, ie face, eyes, etc. I then save as a Tiff.

[Robert Amoruso]

Nick,

Fraser's three-pass sharpening method is discussed in this article.

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

[Chris Starbuck]

Robert,
Thanks for the link! The article is a great 2-page summary of Fraser's book.

[Nick Davison]

Hi all!

Thanks for your help and advice.

I am a Nikon user and currently process my images in LR and CS2. I have always altered my LR default sharpening to the minimum when exporting my RAW file as a TIFF into CS2, but having just read Bruce Frasers article on Roberts link it appears i have been mistakenly making my images soft. I had always thought that no sharpening at all was to be applied before final output sharpening. The article also helps with my initial question about selectively sharpening an area of an image before applying output sharpening.
I feel that my digital workflow is weak but due to the knowledge and generosity of everybody on this forum, i have moved forwards faster that ever before.

Once again, thank you to all of you.

Nick