New Techniques Page: Guide to Image Sharpening

[McQ]

I've just completed a new article for the techniques section of the website: Guide to Image Sharpening.
It's a practical discussion of how to design and apply a sharpening workflow for your photos.

As always, feedback/critiques/suggestions are all welcomed. If you notice any typos or rendering bugs, informing me of these is of course also appreciated. Thanks!

PS: The article isn't yet accessible through the main site, so you need to follow the link above. Just thought I would release it here first...

[carregwen]

I had a quick read, Sean, need to read it in more detail later. As usual, the standard of the tutorials is very good. Technical detail, but put in an easy to understand way.

[Colin Southern]

Looks good to me

[Donald]

Excellent, Sean. Clearly worded. Structured very logically. Can't see any typos etc.

[Dave Humphries]

Hi Sean,

Well up to your usual standard, the only thing I 'tripped over' and re-read to ensure there wasn't a typo was the sentence just after the last two images

With the unsharp mask tool, a setting of 0.2-0.3 for the radius and 200-400% for the amount work almost universally well for downsized images.

I wonder whether "For downsized images, using the unsharp mask tool, with a radius setting of 0.2-0.3 and an amount of 200-400% is almost universally successful." or something like that.

Personal question:
As an alternative to the methods you suggested for masked creative sharpening, another lazy way I do it is to duplicate the background layer, sharpen that, then erase the bits I don't want sharp so it reveals the underlying image. I use the eraser tool at 50% opacity with some feathering and I also vary brush size to suit outline of subject, So it takes two passes to fully erase the sharpened image. Then flatten image when sure I'm happy. Is my way 'just another way', or am I compromising quality by using an inappropriate method?

Perhaps a Tutorial on Layers and Blending modes, advising which is most appropriate for certain tasks would be useful

Thanks,

[McQ]

With the unsharp mask tool, a setting of 0.2-0.3 for the radius and 200-400% for the amount work almost universally well for downsized images.

I wonder whether "For downsized images, using the unsharp mask tool, with a radius setting of 0.2-0.3 and an amount of 200-400% is almost universally successful." or something like that.

Still a little clunky, but how about:
"For downsized images, an unsharp mask radius of 0.2-0.3 and an amount of 200-400% works almost universally well."

Personal question:
As an alternative to the methods you suggested for masked creative sharpening, another lazy way I do it is to duplicate the background layer, sharpen that, then erase the bits I don't want sharp so it reveals the underlying image. I use the eraser tool at 50% opacity with some feathering and I also vary brush size to suit outline of subject, So it takes two passes to fully erase the sharpened image. Then flatten image when sure I'm happy. Is my way 'just another way', or am I compromising quality by using an inappropriate method?

Your method will produce the same results as the masking method, but perhaps with less flexibility. The masking method is really the same amount of work, but has the added advantage of being able to apply levels/curves/blurring to the mask itself. With your "duplicate layer -> brush erasure" method, if you wanted to make similar changes you'd have to redo the entire brush erasure process. Make sense?

[Colin Southern]

Speaking of amounts, personally, my experience is that 0.2 pixels rarely does anything (although on rare occasions where 0.3 is producing frosting I sometimes get a better result by applying 0.2 pixels twice) (usually at 300%)

[Dave Humphries]

Still a little clunky, but how about:
"For downsized images, an unsharp mask radius of 0.2-0.3 and an amount of 200-400% works almost universally well."

Your method will produce the same results as the masking method, but perhaps with less flexibility. The masking method is really the same amount of work, but has the added advantage of being able to apply levels/curves/blurring to the mask itself. With your "duplicate layer -> brush erasure" method, if you wanted to make similar changes you'd have to redo the entire brush erasure process. Make sense?

Yes!

and Yes.
Although I'm not sure I can exactly reproduce the method described on the limited Elements platform, I'll have a go next time.
I know there are workarounds to some of the limitations and the good people here have tried in the past to educate me (back in my first year here), but I couldn't follow it well enough for it to 'sink in' and become a repeatable workflow I should persevere, I know.

Thanks Sean.

I tend to agree with Colin's view and have once used the "double 0.2" method, but the fact that we've used it makes your numbers right although I take his point, so perhaps something that says in the extreme, applying a tiny radius twice might produce less frosting than larger one once.

Cheers,

[Klickit]

I also use Dave's technique of erasing parts of a layer to avoid noise and excessive sharpening etc. I have yet to get my head around masks and blending effectively.
Thanks for giving us more insight into the huge subject of sharpening.

[Colin Southern]

I also use Dave's technique of erasing parts of a layer to avoid noise and excessive sharpening etc. I have yet to get my head around masks and blending effectively.
Thanks for giving us more insight into the huge subject of sharpening.

Another easy way is to simply sharpen everything, and then use the history brush to roll the areas you don't want sharpened back to their previous state.

[Dave Humphries]

Another easy way is to simply sharpen everything, and then use the history brush to roll the areas you don't want sharpened back to their previous state.

If only ...

This is another of those things I don't think Elements can do.

Hmmm, what's a better use of the money; put £600 to CS4 or a lens?
I keep thinking I can do those things another way (in Elements), but the list is growing, so one day ...

The history method has the same limitation Sean pointed out for mine though, doesn't it?

[Colin Southern]

Hmmm, what's a better use of the money; put £600 to CS4 or a lens?

I refuse to answer on the grounds that it might incriminate me!

[Len Martin]

Dear Sean,

great article, extremely helpful.

Until recently most of my images have been jpeg and I've used a very simple unsharp mask facility in a program called Thumbs. Having acquired a Lumix DMC FZ35 I am now increasingly using Raw. Was not impressed with the Raw processing software that came with the camera, so purchased Adobe Photoshop Elements and have been using that - seems quite efficient in reducing noise, and now I understand how to maximise my sharpening facility - thanks to you. Cheers

Len Martin

[ScoutR]

Hmmm, what's a better use of the money; put £600 to CS4 or a lens?

When I was putting together a audio system and trying to figure out which component to replace for the most significant improvement, I was told to start at the source. In my case this meant a better turntable so I could play vinyl LPs without distortion, pops and clicks. OR I could have used my editing software in order to remove the problems caused by the less than ideal source. The later is possible, but very time consuming and editing always introduced artefacts.... sound familiar.

Same applies here, no question in my mind what I'd do if I had the extra money.

Wendy

[arith]

I read most of it up to the bit about masks. I can't find a mask in PSE7 but I know I could do similar in Gimp. Nowadays I don't do any capture sharpening or Noise reduction in ACR but go straight to third part noise reduction, then third party sharpening where detail is split into small, medium and large and further subdivided to sharpen or and boost, which is confusing but interesting.
Sometimes when downsizing I sharpen more using an unsharp mask but mostly I use the high pass filter or nothing.

The tutorial made perfect sense to me and up to where I read was well written. cheers

ps the cheapest L type a 17-40mm f4 is a bit past it and costs more than £600, I'm amused by the price of some lenses 50mm f1.2 L £1350 but almost as good on a full frame but rubbish on a cropped camera 50mm f1.4 £309 in Jessops.

[McQ]

If only ...

This is another of those things I don't think Elements can do.

Hmmm, what's a better use of the money; put £600 to CS4 or a lens?

£600 to CS4 is pretty steep. I'd lean towards a lens for now, depending on which ones you already have. It will also improve image quality, and you can always re-process your old images whenever you DO get Photoshop CS5. Much easier than re-taking all your old images when you get a new lens!

The history method has the same limitation Sean pointed out for mine though, doesn't it?

Yes, it does, but it also has the advantage of perhaps being a little easier. On the other hand, perhaps it makes it more difficult to see where you have and have not applied creative sharpening...? Not sure as I don't normally go this route.

[Dave Humphries]

£600 to CS4 is pretty steep. I'd lean towards a lens for now, depending on which ones you already have. It will also improve image quality, and you can always re-process your old images whenever you DO get Photoshop CS5. Much easier than re-taking all your old images when you get a new lens!

True.
The figure was plucked from the air; I have been offered special 1/2 price CS4 upgrades by Adobe from my registered Elements 6, but I expect that'll stop now CS5 and Elements 8 are out. That was about £290.

I think it will be a lens, either the Nikon 105mm f2.8 VR AF-S macro, or Nikon 300mm f4 AF-S telephoto, the first is about 600 or the latter about a grand (pounds). I currently have the 18-200mm VR and a couple of totally manual film era macro lenses (55 and 90mm). Just can't afford what I'd really like in the telephoto range.

Yes, it does, but it also has the advantage of perhaps being a little easier. On the other hand, perhaps it makes it more difficult to see where you have and have not applied creative sharpening...?

True again, at least I get the little layer thumbnail showing the erased area as checker board in the Layers dialog, so I can see if I have "missed a bit"

Thanks,

[Colin Southern]

On the other hand, perhaps it makes it more difficult to see where you have and have not applied creative sharpening...? Not sure as I don't normally go this route.

In theory (and theoretically in practice too I guess!) ... but in reality I find it useful where I want to get quite agressive with sharpening (usually low radius / high amount) to reveal texture in a particular area - but - where that amount produces something undesireable in another area. So I apply it to the entire image and then just wave the history brush over the damaged area (or other areas as well) - in practice one doesn't usually have to be particularly precise.

Definately a "quick and dirty" trick, but works quite well for the sorts of images I create.

[rick55]

Hi, Sean;

This is a wonderful tutorial: very clear and very comprehensive. A couple of comments/questions.

At the end of the "How It Works" section, the three example photos are a bit small to really see the effect: could they be enlarged?

In "Sharpening Workflow," in the "Capture Sharpening" paragraph, I don't understand the part about "Capture sharpening aims to address any blurring caused by your image's source, in addition to any image noise and detail characteristics." Sharpening can enhance noise, as you describe very well in the capture sharpening section? I know ACR has noise reduction in the sharpening tab, so maybe that's the point.

In "Output Sharpening," I wonder if it would be better to have the original image also show the tightly cropped area that appears in the sharpened versions.

Cheers,
Rick

[McQ]

At the end of the "How It Works" section, the three example photos are a bit small to really see the effect: could they be enlarged?

Yes, I should provide better examples. I wasn't going to put them in originally since I'd added the four radius examples with the eagle head, which illustrates a similar concept.

In "Sharpening Workflow," in the "Capture Sharpening" paragraph, I don't understand the part about "Capture sharpening aims to address any blurring caused by your image's source, in addition to any image noise and detail characteristics." Sharpening can enhance noise, as you describe very well in the capture sharpening section? I know ACR has noise reduction in the sharpening tab, so maybe that's the point.

ACR's masking setting should also be set with noise levels in mind. I should reword that to:
"Capture sharpening aims to address any blurring caused by your image's source, while also accounting for image noise and detail."

In "Output Sharpening," I wonder if it would be better to have the original image also show the tightly cropped area that appears in the sharpened versions.

OK, I will add an overlaid box which shows where the full size crops are being taken from. I've done that in other articles.

Thanks for the comments.