Question on Photoshop CS5 extended: sharpen tool

[RichardsTPF]

Just start to learn PS.
I did a little bit of research on adobe web, and found unsharp mask, smart sharpen, sharpen filters and sharpen tool.
What sharpen tool do you use, and which one do you prefer and why? I know I can find too many info online, good ones and crabs. I have seen a lot of members have great PS skills here, I want to see your opinion. Then I can focus on one or two (or more) techniques first.

 

[Big Mike]

Sharpening can be a rather complex subject. There are books dedicated just to sharpening.
I'd suggest that you keep doing lots of reading & viewing on the Adobe site network.

For a long time, I used USM (un sharp mask) in Photoshop. (Photoshop CS, which doesn't have Smart Sharpen).
I would also use a technique often called High Pass sharpening. I believe it uses the exact same sharpening technique as USM, but because it was layer based, was a little easier to customize.
Now, with a newer version of PS, I will use smart sharpen (if I do any sharpening in PS). Although, I couldn't tell you the technical difference between SS and USM.

But what I do now...is mostly just sharpen via Lightroom. The sharpening inside LR comes from a company/program called Pixel Genius / Photokit Sharpener. Again, I couldn't explain the technicalities of it...I just use it.

But, the key to using sharpening, is to realize that different images will require different amounts (or even techniques) of sharpening. So it's not so much about finding setting/techniques that work, and then always using them....it's about finding what what works for at particular image. To that extent, when i'm really into heavily editing an image, I'll apply selective sharpening, so different areas may get different amounts of sharpening.

And lastly, note that 'sharpening' isn't about taking photos that are blurry and fixing them. For example, unsharp won't correct for missed focus or motion blur (although, it can disguise them a bit). What sharpening actually does, is increase local contrast.

One reason why sharpening is such a big deal in digital photography, is that most digital cameras have an anti aliasing filter in front of the sensor. This is to prevent moire from forming when photographing something that has a pattern to it. Unfortunately, a result of the filter is that it robs some possible sharpness. A few cameras, the Leica D9 for example, doesn't have an AA filter, and is thus capable of incredibly sharp images. You just have to watch out for moire. (Lightroom 4 is coming out soon (currently beta), has an moire correcting brush tool).

 

[Hardrock]

To add to what was said above you also treat sharpening to certain images very different. ie: a portrait you probably don't want to do a global sharpen to due to sharpening of the back ground. The same with most macro subjects if you global sharpen it will take your smooth back ground and add artifacts to it. Where as with a landscape you want to global sharpen most likely to improve the sharpness of the entire image. NIK has a great and easy plugin to CS for sharpening global and local.

 

[unpopular]

What I do is place one high pass filter on soft light with a radius of about 25, then another on overlay with a radius of 3 and another with a radius of 1 and sometimes a fourth with a radius of 0.5. I then cut back the large radius until it doesn't look overcooked. The large radius filter is more used for local contrast than it is for sharpening.

If I am getting lots of speckles, I either cut the opacity starting with the smallest radius.

If I am getting lots of halos I can either mask out the larger radius high pass filters, or I duplicate the image, enable only the offending highpass filter layer and flatten the duplicate. I then copy this onto it's own layer, deactivate the highpass filter and place the flattened version on a mode such as "darken color".

 

[KmH]

I rarely sharpen an image globally.

Mike mentioned that the company Pixel Genius is who Adode got it's LR sharpening.

Pixel Genius was Bruce Fraser's company. Bruce has passed on and Jeff Schewe now carries the torch. I highly recommend - Real World Image Sharpening with Adobe Photoshop, Camera Raw, and Lightroom (2nd Edition)

In addition to the Photoshop ACR Sharpening panel and Adjustment brush (Camera Raw/Lightroom) and the Shapening filters in CS5, some have mentioned high pass sharpening. There is also luminosity sharpening, and techniques for sharpening in LAB mode. Enhancing mid-tone contrast provides a kind of sharpening effect.

Many don't know that USM can be used to make local contrast adjustments, in lieu of sharpening, though I often do local edits using USM in both ways in the same local edit.

The range of techniques that can be use to make an image appear sharper is only limited by one's understanding of how to use image editing software to full effect.

 

[unpopular]

^^ I think though that the correct application of highpass will do everything USM will, but more naturally.

It's also worth pointing out that that you can create your own unsharp mask by placing a gaussian blur filter layer on difference mode and blurring the the result. The first blur acts as "threshold" and the second acts as "radius". You can then apply a curve to the mask for fine tuning and use the mask however you see fit; for basic sharpening, just use a contrasty curve adjustment layer with the mask in place. This allows you to very easily control every aspect of the USM sharpening, not only the quality of the mask, but also how edge contrast is carried out.

In practice though, I very seldom actually do this.

 

[unpopular]

I just now discovered another sharpening technique which sort of combines USM and HP.

1) Copy the image layer
2) Add a blur filter on "remove" mode, drop the radius so that only a delicate outline of the detail remains.
3) Place the copy of the image layer and the blur layer in a group. This is important so that you can modify the sharpen afterwards
4) Add a highpass filter in normal mode to the group.
5) Place the group in Overlay Mode.
6) Adjust the highpass radius to adjust halo.

Hopefully you can do all that in Photoshop, you should. I'm using Photoline.

 

[KmH]

It's also worth pointing out that that you can create your own unsharp mask by placing a gaussian blur filter layer on difference mode and blurring the the result. The first blur acts as "threshold" and the second acts as "radius". You can then apply a curve to the mask for fine tuning and use the mask however you see fit; for basic sharpening, just use a contrasty curve adjustment layer with the mask in place. This allows you to very easily control every aspect of the USM sharpening, not only the quality of the mask, but also how edge contrast is carried out.

In practice though, I very seldom actually do this.

UnSharp Mask originated as a film darkroom technique using 2 negatives.

 

[unpopular]

yep I can't remember the procedure though, I never actually have done it. Mostly because i'm lousy at registration.

But it's pretty much the same idea with digital. USM, be it digital or traditional, is really nothing more than a contrast adjustment masked to the difference in gaussian.

 

[RichardsTPF]

Thank you for your detail advise.
Looks like I am going into a new world. You give a direction to start with.

On adobe web page, it says "The Smart Sharpen filter has sharpening controls not available with the Unsharp Mask filter. You can set the sharpening algorithm or control the amount of sharpening that occurs in shadow and highlight areas." What that means, is it more advanced filter? Sounds like the Smart Sharpen filter can replace the function of Unsharp Mask filter.

I found this tutorial: Smart Sharp
It combined several tools to only sharp the edge of image. Complicate method, looks useful. What do you think?

Keith, I will definitely look into that book.
Again thank you all.

 

[unpopular]

From what I have used in the past with smart sharpen, it is very good and gives you a lot of the control which you can only otherwise achieve by building your own mask. I kind of forget about it, because I haven't use PS for so long. But it is a very viable tool.

Still, I think you ought to look into highpass sharpening. Many people use HP in conjunction with USM.

 

[Big Mike]

Still, I think you ought to look into highpass sharpening. Many people use HP in conjunction with USM.

From the way I learned it and the examples I've seen....USM does exactly the same sharpening as Highpass sharpening. I forget the proof, but you can do something that shows that what it's doing, is exactly the same.

But, I still liked to use HP because of the way it uses layers.

By the way...I just watched part of a great tutorial video where the above mentioned Jeff Schewe comprehensively explained the sharpening in Lightroom. Very interesting stuff. I know a lot more about it, than I did this morning...but it's going to take a while for it to sink in.

 

[unpopular]

All sharpening techniques pretty much work the same: they find edges and increase contrast selectively accordingly. It's a matter of edge detection.

I am not really sure that HP/overlay and USM/normal are doing the exact same thing, halo always to be better controlled in HP than in USM, making it better for contrast adjustments.

 

[Majeed Badizadegan]

Besides the tools native to CS5, there are lots of plugins available from Nik Software, OnOne, Topaz etc. that have tools specifically for sharpening. You might find you like a plugin over what is available in CS5.

 

[KmH]

The point is that sharpening is not a one trick pony.

Each image has to be evaluated on it's own merits and then you choose one of the many techiques and values to accomplish your editing goal.

Almost every day someone discovers a new way to use PsCS5 (Photoshop 12, ACR 6, Bridge 4) that the designers never imagined was even possible.

And PsCS6 (Photoshop 13, ACR 7, Bridge 5) is on the horizon........