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Sharpen your Image with Nik Sharpener Pro 2
A Photoshop plugin to sharpen images for screen and print
All images need some form of sharpening for print or web use, the tricky bit is how much and where to apply it.
Keith looks at the latest Photoshop plugin from Nik Software (or Nik Multimedia as was) and finds out just what it can do.
Sharpening - the key to good prints
Any digital capture or printing process introduces a certain softening of images that needs to be fixed.
The problem is that different input devices (scanners, cameras) produce subtly different kinds of softening, whilst the optimal amount of sharpening for a print depends on the size of the print, it's viewing distance, the materials used and the make of printer.
Add to that, the need to sharpen different parts of images different amounts and you can see that it's going to take a lot of testing to gain the experience to get the best results.
In the face of this, many people either apply a 'general sharpening' to all their prints, or more often leave it out all together.
Even if you are going to put images on the web there is a certain amount of sharpening that will give your images that extra 'punch'
Take for example the picture to the right (actually taken from Nik's own web site ;-) and compare it with the one below that I've sharpened (30%) with the 'display' setting of Sharpener Pro 2.
A slightly sharper version of the image above.
Which one would catch your eye the most?
Which one looks 'better'?
One problem with just applying a fixed amount of sharpening is that it does not take into account how sharp the existing image is to start with.
If you have resampled an image with the Photoshop 'Bicubic Sharper' method rather than 'Bicubic Smoother' it will require a different degree of sharpening.
There are many ways of sharpening already available in a package like Photoshop (even more in CS2). I'll cover a few in the discussion at the end, but first what does Sharpener Pro 2 do?
The software (demo available) is an updated and expanded version of Version 1, which has been widely used for some time.
In addition to offering a normal Photoshop plug-in, there is a 'selective' sharpening interface.
This allows for layer based sharpening rather than the usual image altering approach -- think of the difference between altering the levels of an image by an adjustment, or an adjustment layer.
One key feature (Autoscan) is that the software will attempt to analyse your image and only apply sharpening where it thinks it's needed.
There are two versions of the software available: 'Complete' and 'Inkjet'.
Note -- Not having a printing press handy, I've just been looking at the Display, Epson inkjet settings and Raw Presharpening settings in this review
The picture below shows the options available in the complete version.
'Display...' is the setting for screen (web) use, and all except the last one are for different printing technologies and manufacturers.
That last 'Raw Presharpening...' option is available to add some initial sharpening to images converted from camera raw files (see Keith's "Why Use RAW" article for more info on raw formats).
The whole question of when to sharpen images is a contentious one. Most raw file conversion software will offer various amounts of sharpening in their processing of images. Some converters may not even offer you the choice, and your camera may well be doing some sharpening of its own behind the scenes.
My own preference varies by image type. If I'm covering a corporate event where I may have 2-300 raw files to process, I'll often add some sharpening in 'Adobe Camera Raw' when I'm converting/opening them. This is just part of my workflow when I'm handling a lot of images. When I'm working on one image I may be using a different converter and will be expecting to spend quite some time on that particular picture. Here I may convert with no sharpening and selectively apply some sharpening to an image before re-sizing. I'll show an example of this in the when to sharpen section, but suffice to say, the Raw Presharpening is a powerful tool if applied carefully as part of your imaging workflow.
Any printing system produces a degree of 'softening' of images -- just think of tiny drops of ink on paper, the drops spread out as they meet the paper. The degree and type of blurring varies with printer technology and paper type. Nik Sharpener Pro allows you to provide variable amounts of sharpening, depending on a range of image characteristics.
Some of these characteristics can be calculated, others are a bit more up to your own preferences, however all are adjustable to get the results you want.
I'll show some examples from one of my pictures of the ruins at Mesa Verde. I'll not go into details on the various interface elements since there is lots of information on the Nik site, including the full PDF manual.
Remember that I'm showing examples as compressed JPEG files on a website, where the images may be meant to be printed, on a particular printer... In other words, don't use the images in this review to make too many judgements on actual performance - try the demo!
It's also worth pointing out that many of the examples are shown at 100% pixel size, not the actual print size, where screen resolution would not show the sharpening correctly anyway. Almost any print sharpening -should- look excessive when viewed at 100% pixel size.
First look at the difference in sharpening for different printer resolutions...
Much less sharpening is needed for the higher printer resolution.
Note that this is PRINTER resolution, not file resolution. There is often confusion over this. I frequently print files on my Epson 9600 at 240dpi (or ppi if you want to be picky :-), but the printer resolution is usually 1440dpi. You may see lengthy debates elsewhere on the optimal file resolution, and various pronouncements as to the optimal value (often 360 for Epson printers).
Well I have to say I've tried several, and when using my 9600 with the ImagePrint RIP I can't see much difference. There may be a slight difference, but I'm interested in getting good pictures that have an emotional impact on the viewer, and there comes a point where you just have to say "this is it - it's finished, it's good enough for me". Whilst I understand the fascination of all the argument and testing ... I've got photos to take and prints to sell :-) There is an good article all about resolution at LTL Imagery.
Even greater differences in optimal sharpening levels are dependant on viewing distance. Close up prints need to keep fine detail that is not needed if you know the prints will only be seen at a distance.
And now for the same print at over 3 metres...
This is very useful if you know that a particular print is to be placed where nobody will ever get close to it.
There are also settings for paper type, that I've not shown here -- they are more subtle and don't show up well in web pictures.
If like me, you produce lots of prints at certain settings of the plugin, you can pre-define your common ones to help ensure consistency.
Here I've defined two sets, for two particular papers I'm using on my 9600 printer.
The plugin settings include other information that you might not have thought made a difference, such as whether you are using 4 or 6 inks. It is well worth collecting together your commonly used settings when you first install and run the plugin.
The image in the preview pane can be displayed in a number of different formats (see the Moon pictures below) that help compare different settings. You can also apply an overlay which shows how much sharpening is being applied to different parts of the image.
Displaying images in web pages usually requires sharpening them. There is the example at the top of the article from the Nik site, but the one below show two of my pictures, resized in Photoshop, for web use.
If you move your mouse over the first image you can see just what changes in the sharpening process. Although the 'Display' setting will attempt to estimate the correct amount of sharpening, I find that I often adjust the slider to get the optimal amount for my own taste.
You should always be wary of cumulative sharpening errors when handling images for web use.
If you reduce an image using the bicubic sharper method, then some slight sharpening is introduced. Reduce the image still further and sharpening artefacts can be exaggerated.
It is easy to overdo the sharpening, so just be careful and check images. This is important if you have sharpened a large number of images in a batch action (and the plugin is fully compatible with actions and scripting)
I've covered some other related aspects of using images on the web in another article on this site.
The photograph below of the Moon and a well known Leicester landmark encompasses several possible problems with applying sharpening evenly to an image.
The photo was shot with an f10.5 1100mm lens, and even though the tower is about 5-600 metres away it is not in focus. For the screen version below, I've just sharpened the whole image with the 'Display' setting until the edge of the moon is just starting to be over sharp (look for the slight artefacts on its lower edge)
For a larger print, I'm only really looking to sharpen the Moon. If I just apply an overall sharpening, any noise in the dark blue sky will be exacerbated, as you can see below. Note also I've changed the display mode to compare before and after.
Sharpener Pro 2 does have an autoscan function which varies the amount of sharpening over the image, depending on the content, but I found that it could often be fooled by noise in my images. Fortunately there is an advanced mode where you can selectively alter sharpening for different colours (selectable with the eyedroppers).
In the example below, I've reduced the sharpening for the blue sky and very dark tower.
Given that the blue channel is often the noisiest in camera sensors, this works well.
This example image also allows me to demonstrate the amount of sharpening that the software is applying.
First the original 'sharpen everything' -- The density of the stripes is proportional to the degree of sharpening
Next with the blue 'turned down' -- note that there is still some sharpening in the very dark area.
or you can see just the mask (with sharpening in the dark area turned down as well)
A little thought about the image however, indicates that I really need not apply sharpening to anywhere else in the image other than the Moon.
Whilst you could sharpen a copied layer and mask it appropriately (perhaps with blending mode set to luminosity) there is an easy way to provide selective sharpening to images.
Sharpener Pro 2 has another mode of operation where you can mask it's sharpening more directly. The selective mode is activated from the Automate menu and allows any of the normal sharpening filters to be applied in varying amounts, according to a mask you can paint in.
As you can see below, a duplicate layer has been created. I've painted in the sharpening with a mask. The white bit is where the sharpening will be applied -- you can see how it matches up to the position of the Moon in the image.
This example has a simple sharpen/do not sharpen selection, but you could use the mask to provide much finer control.
Sharpening is a one way process, it's destructive to image data. Maybe not much, but the effects are cumulative. It follows from this that you want to be careful when and where you apply it to your images. When I'm working from a raw image or scan I keep the image at its original size for as long as possible. I create print versions of the 'Master' file for each print size I want to produce.
Note that I always keep the original raw files, just in case I need to go back to them or some new whizzy software comes along (see 'Why use RAW?')
What about sharpening in my master file? This depends to some extent on the image and its intended use. The example below shows a 100% sample of a Canon 1Ds image that has been enlarged by 300%(bicubic smoother) and sharpened for print use (a 50"x33" print). If you move your mouse pointer over the image, the centre section shows the same image(slightly offset), but where some slight raw presharpening was applied after conversion.
The first view is fairly soft, and in a large print this would show as a serious lack of detail. The version with raw presharpening would give much better results - this is a huge print so you would expect people to view it from a reasonable distance.
If you want to see a good example of cumulative image destruction, take an image and downsize it by 10% steps using Photoshop's Bicubic Sharper method.
The kind of resampling technique you use also has an effect. Once again we are in an area where endless discussion take place on the web, generating much heat but very little light. My own guide is to use photoshop resampling for size reduction and upsampling to say 300%. Over this I might consider specialist software, but then again it might look alright using Photoshop -- depends on the image, its use and what the client wants/is willing to pay for....
There is a third aspect to sharpening in any workflow from captured image to print and that is 'creative sharpening'. It's where you sharpen or blur different parts of the picture to change the emphasis of different parts. An example might be selective sharpening of the eyes in a portrait, where the viewers attention is naturally drawn to the sharpest bits of an image. Equally well you might want to blur some parts of an image to de-emphasise them. This is one part of sharpening that relies on your creative input... I use all the built in Photoshop tools for these kind of effects.
One other sharpening related area that should be mentioned is where you are correcting image faults, such as camera shake or out of focus areas. There is specialist software available for this such as Focus Magic which I've found invaluable for fixing the odd non-repeatable shot that's gone a little wrong :-)
2009 - We now have a review Sharpener Pro V3 - the latest version of this software
The software is easy to use and comes with comprehensive and clear help files and an informative manual.
If you have not been applying specific sharpening to your images before printing, then the results should be astounding, even if you have been sharpening your work, then the improvements should be quite noticeable.
The software does exactly what it says on the tin...
One of the difficult choices when sharpening is to decide how much to apply. It is very difficult to judge the right amount of sharpening for printing, when viewing images on a screen. Nik Sharpener Pro 2 makes a very good first approximation in its analysis of your images. You set a few parameters, let it analyse the image and the right type of sharpening is applied.
There is a lot of information in the plugin interface and the text seems very small sometimes, which might be a problem for some. It's not badly laid out at all, just a bit small.
You can see the results of the software's analysis by changing the display mode of the plugin, it can show an overlay of the varying amounts of sharpening it is applying - maybe it was just my images, but I rarely saw much difference in this display. It showed up nicely in the Moon pictures above, but they are not that typical of my work.
The Advanced mode helped in avoiding unwanted sharpening in skies and areas of flat colour. The Selective mode was useful with prints where there is only a small bit of detail in a large amount of soft background (the Moon picture above, or a mountain poking through cloud)
Given the range of image sources and what may have happened to them during processing, I found that the printed results were very good. Some of my black and white prints with snowy mountains and trees showed slight oversharpening in areas and some visible sharpening artefacts.
With experience, you learn to spot such problems and fix them. For example, the distant trees against snow -- I just used the history brush and painted in some of the unsharpened image (fine brush ~20%). This softened the unwanted effect, giving me a print I was happy with.
If you are not used to sharpening your images for different print sizes and settings, then trust what the software tells you. You will quickly learn to fine tune your sharpening, but I found that the majority of large prints I was making were just right. Remember it's about what the final print looks like and whether you are happy with it.
Now I hear people saying "I could do all of that in Photoshop"
Well, to some extent you can, there is the sharpening available in ACR for your raw files, and the new Smart Sharpen filter offers specific deblurring options.
You can still use unsharp masking with blended high pass filter layers and lots of other techniques (some links below)
What I like is the printing side of Nik sharpener -- If I want to make an 8" x10" print I produce a version of the file sharpened for that size. If I want a 27" x 16" version, then one that size gets made as well.
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If I change paper type, then I'm confident that the sharpening side of the change is just a different setting.
Nik Sharpener Pro 2 is likely to be a standard part of my workflow when I'm producing my best prints.
There is a demo version of the software available, along with a full user manual.
*Oct 2005 I used the software a great deal for sharpening prints at a recent exhibition, and have written an article covering some of the issues.
* 2009 We have a full review of Version 3 of the software.
The views in this article represent those of Keith Cooper.
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