Sharpening in Photoshop

As Photoshop is what I use, that's what the thread describes, so for those who find that useful that's excellent. I was just thinking that for Lightroom users another thread could highlight procedures and differences, but someone else will have to do that one.

Generic sharpening comments could belong in either quite happily, but I just want to avoid confusion, if at all possible.

Ok, no probs.

The radius question and how images of different sizes may require different sharpening still stand, then.

Mind you, I've just gone off to learn about the radius setting so no worries about that one. Haven't tried to use it in anger though.

What do you need expanding on the original post darksies? It does cover different sharpening for different sizes, so how would you like that explaining further?

Oh yeah, so it does! Sorry about that.

Trouble is, I didn't understand it when I first read it as I didn't know what radius did! I do now!!

Thanks.

Am I right in thinking that the size of the actual image (as a file) is immaterial, what matters is the size of the viewed image?

To clarify.

An image at a web size of say 600x400 will require one level of sharpening which (allowing for subject differences) could be applied to web images of any size viewed at 100%.

An image of 1800x1200 destined for printing at 300 ppi to provide a 6x4 print will require more sharpening because the effective reduction in size from the on screen image to the print will reduce the impact of the sharpening. Because of this, rightly or wrongly, I judge sharpening for prints with the image reduced to (say) 25%.

Am I also right in thinking however that another factor may be viewing distance, eg an A3 print likely to be viewed from some distance will benefit from greater sharpening than the hand-held snapshot?

I was looking at it purely from the number of pixels in the image. We view them on screen the same, so that does make it harder to judge, but say a print at A3 does tend to need more sharpening than a web image.

Of course having a ball park figure in mind works most of the time, but individual shots may need less or more sharpening depending on subject matter. A Grade II Listed black and white manor house will take more sharpening than a portrait would, whilst retaining the quality we would like.

In the case of a portrait a craggy old face might suit higher sharpening than a young female model, most of the latter not welcoming seeing every pore of their skin reporduced in staggering detail.

To answer the original query, as the image with the higher pixel count will be the bigger print, then you could consider the pixel count to be the same as the size of the image as viewed. Don't get too hung up on this as it could well lead to confusion. Keep it simple.

The way I see it, John, is that I now have a little more knowledge and a little extra in the tool box. I can now use this to see if I can make any extra small improvement to any image.

It's how an image looks that's the important point.

One of the contributors to the Olympus UK site came up with a set of custom filters for photoshop for minimal/slight/more/strong sharpening. I loaded these onto my copy of CS3 and use these for sharpening. It quickens the process for me anyway. Hopefully I can post a link to his website where these are detailed. http://www.snaar.co.uk/snaarp6.html

It's interesting the different approaches people have. For web sized images I typically choose a small radius (0.2 or 0.3) and a large amount, to sharpen fine details without creating large haloes. I also use Focus Magic plug-in sometimes, more for 'corrective sharpening' rather than fine tuning a resized image.

For prints I just tick output sharpening in LR3.

John, in your K-5 menu do you set +1 for "sharpness", or "fine sharpness", or "extra sharpness"?

Thanks.
Philip

"sharpness" - I do this to satisfy the requirements of fotoLibra. Ironically, their clients do not want any sharpening in software but are happy to accept in-camera sharpening.

So much for saying the PC is more capable than the camera itself!

I've used High Pass sharpening for years, no halos or artifacts, or, more accurately, difficult to get halos and artifacts, the basic method is here

http://www.westfield-photo.org/high%20pass.html

But there is an advantage in turning your image into a Smart Object first as you can then adjust the slider after applying the filter and the usual Smart Object advantages.

Foto-Libra has accepted my images sharpened this way for years.

As Pentax don't apply any sharpening when shooting Raw only in the Raw to Jpeg conversion, how can in camera sharpening be better than controlled sharpening in PS? The new K5-IIs would change that as little (if any) sharpening is required, but it certainly is with images from any camera with an AA filter.

Any discussion of Photoshop's native sharpening options would be incomplete without mentioning Smart Sharpen. If Lens Blur and More Accurate are selected, you get a deconvolution sharpening method that does a great job of tightening up the image and drawing out small details - much better than Unsharp Mask. Adjusting the Radius slider is akin to adjusting the Point Spread Function in a standard deconvolution process. Use with caution, and always use the Advanced options and fade the Shadows and Highlights to lessen haloes.

You can also reduce sharpening artefacts by sharpening on a separate layer (set to Luminance, as previously suggested) and doing a custom blend on that layer - setting the Blend If values to gradually fade out at either end, thus concentrating the effect on midtones.

Lastly, I would add that increasing mid-tone contrast is another good way of increasing perceptual sharpness. The easiest way is the USM method - make a new layer (set to Luminance) and apply a wide-radius USM to it: say, Amount 20, Radius 60+, Threshold 0. Then do a custom blend as described above to avoid blocking up shadows and highlights, and adjust opacity to taste. Works very well, especially when printing on matte paper.

Editing takes up too much of my time as it is so I choose the easy way out & use the excellent plugin "Pixelgenius Photokit Sharpener 2.0" developed by Martin Evening, Jeff Schewe and Bruce Fraser...saves all the hassle and produces great results

Simon

Another important consideration when choosing an appropriate sharpening method has to be if it is destructive or non destructive. If you choose a destructive option (ie working directly on a pixel layer on a rendered file) then you would choose to 'save as' each different versions for each different purpose (ie web or print).

In John's case, his camera JPEG +1 setting would be considered a 'Capture Sharpening', and ideally this file would remain untouched as a 'Master'. Any destructive sharpening to the base image pixels(the 'output sharpening') would need to be saved out as new JPEGs for each purpose (and sized appropriately also).

An alternative though would be to work in a non-destructive manner, which would include any layered techniques (such as the High Pass for example) and maintaining the original base layer as the 'Master'. You could then create a different layer with the specific shapening applied for each output and simply switch the other layer off when saving out each version. In this way your 'Master' file includes ready made output shapening options there already - very handy no doubt if sending the file to anyone else for printing different sizes if needed.