Sharpening

[Mike Farley]

I presented at Horsham Photographic Society earlier this evening and one of the slides I put up had some suggested unsharp mask values. I promised to post it to the forum for their members to refer to as well as being useful for others.

These days, most of my printing is done via Lightroom and I find that its built in automated sharpening tool works well, but these are good starting points when working with Photoshop. The penultimate setting is not really a sharpening function, but works because sharpening is actually a contrast control. Some additional shgarpening might still be necessaeyy after it is applied.

I normally set a 100% view when sharpening to ensure that no halos are being produced by oversharpening, then reduce the view to 50% to judge the overall effect.

• Amount – 150%, Radius 1, Threshold 0 (for prints with a lot of detail - it is possible to push the amount value to 180% or even a bit higher)
• Amount – 150%, Radius 1, Threshold 10 (for prints with subjects such as flowers, pets, people)
• Amount – 50%, Radius 3, Threshold 0
• Amount – 225%, Radius 0.5, Threshold 0 (Products, landscapes)
• Amount – 65%, Radius 4, Threshold 1 (General purpose)
• Amount – 65%, Radius 4, Threshold 3 (Maximum)
• Amount – 20%, Radius 50, Threshold 0 (Pops a B&W image)
• Amount – 200%, Radius 0.3, Threshold 0 (Web)

[davidc]

It could be a lot of work if you don't already have examples but I'd be interested to see what result each of those levels produces - ideally with the same image perhaps? Maybe colour/mono versions? Were there examples on the slides you presented maybe?

[Mike Farley]

It could be a lot of work if you don't already have examples but I'd be interested to see what result each of those levels produces - ideally with the same image perhaps? Maybe colour/mono versions? Were there examples on the slides you presented maybe?

This isn't going to work, is it? Due to the differences between screen and print resolution, images require different levels of sharpening depending on how they are going to be viewed. An image correctly sharpened for print will look oversharpened on screen. There is also the issue that depending on the particular circumstances of any given image, the amount of sharpening required will differ. The values given are indications of what can work, but might need to be adjusted. There are no hard and fast rules, neither will everyone want the same amount of sharpening applied to their images.

As a general indication of my own methods when using Photoshop, with printing I start with the setting at the top of the list and use the last setting for output to the web. If an image is not quite sharp, sometimes it can be salvaged with the suggested maximum setting, but even then it might not be possible to print it too large. Downsampling and keeping things small can help mask some sharpness issues.

[davidc]

An image correctly sharpened for print will look oversharpened on screen

It's specific things like this I was hoping to see actually - I've heard of this as a principle but never seen an example of what's thought to be correct for print yet oversharpened for screen. Typically I use the same setting for both and not felt like it was lacking sharpness in either format but I'd certainly like to see how others do it.

I'm going to google this, if I find any examples I'll post it back.

[davidc]

Here's one that has a single image comparison for print v screen - http://www.cambridgeincolour.com/tutori ... pening.htm
It's interesting in that it suggests for prints with a lot of detail you should lower the radius, below 1 in the case presented. So if you have large areas without detail and small areas with detail, use a large radius. For areas with lots of fiddly detail use a small radius.

[davidc]

Just as an FYI, this is the method I've been using for my image sharpening.

http://petapixel.com/2013/03/15/psa-say ... ur-photos/

I also recommend using the alt key to preview the effect of sharpening as you tweak things, really useful.

[Mike Farley]

An image correctly sharpened for print will look oversharpened on screen

It's specific things like this I was hoping to see actually - I've heard of this as a principle but never seen an example of what's thought to be correct for print yet oversharpened for screen. Typically I use the same setting for both and not felt like it was lacking sharpness in either format but I'd certainly like to see how others do it.

I find that using something along the lines of the web setting in my original post gives a gentler effect than the print one when viewing on screen. I have seen recommendations to set Amount to 400%, but find that this rather overcooks things and I settled on 200% as a starting point.

The amount of sharpening to be applied is always going to be down to personal taste and will involve a certain amount of experimentation.

[Mike Farley]

Just as an FYI, this is the method I've been using for my image sharpening.

http://petapixel.com/2013/03/15/psa-say ... ur-photos/

I also recommend using the alt key to preview the effect of sharpening as you tweak things, really useful.

I played around with Smart Sharpen when it first came out a few years ago, but preferred the results I got from USM. It could be worthwhile revisiting it to see if my tastes have changed in the interim. It is also possible that Adobe has tweaked the algorithms in later versions.

[davidc]

I suspect it has. It was first introduced in CS2 back in 2005 and been overhauled a fair bit since then - as the article says, some sharpening methods were focused on scans rather than photographs.

[Mike Farley]

A quick Google has shown that it was updated for Photoshop CC last year. I am not sure about any other changes before then. If it the new Reduce Noise function helps with the problem of artefacts appearing in out of focus areas, then it is definitely worth investigating further for those odd occasions when I do not use Lightroom sharpening.

http://blogs.adobe.com/jnack/2013/07/qu ... op-cc.html

http://www.adobepress.com/articles/arti ... ?p=2101517