Adobe Photoshop CS5 for Photographers - Martin Evening [295]
High Pass filter edge sharpening technique
The technique that's described on pages 682–683 shows an example of just one of the formulas used in Photokit Sharpener for output sharpening. In this case I have shown Bruce Fraser's formula for sharpening a typical 300 pixel per inch glossy inkjet print output. You will notice that it mainly uses the High Pass filter combined with the Unsharp Mask filter to apply the sharpening effect. If you wish to implement this sharpening method, do make sure you have resized the image beforehand to the exact print output dimensions and at a resolution of 300 pixels per inch.
1.
The sharpening method described here is designed for sharpening an inkjet print on glossy paper at 300 ppi. To begin with, make a duplicate copy of the Background layer and set the layer opacity to 66%, then double-click on the duplicate layer to open the Layer Style options and get the Blend If sliders to match the settings shown here.
2.
Next, apply the Unsharp Mask filter to the layer using an Amount of 320, Radius of 0.6 and Threshold of 4. Then choose Edit Fade, change the blend mode to Luminosity and reduce the opacity to 70%.
3.
Now change the Layer blend mode from Normal to Overlay, go to the Filter menu, choose Other High Pass filter and apply a Radius of 2 pixels. Here is a 1:1 close-up view of the sharpened image. Remember, you can't judge the sharpening by looking at the display, but you should be able to judge the effectiveness of the technique by how sharp the photograph appears here in print. Note that the sharpening layer here can be increased or decreased in opacity or easily removed and that the underlying Background layer remains unaffected by the preceding sharpening steps.
Gamut warning
The View menu contains a ‘Gamut Warning’ option that can be used to highlight colors that are out of gamut. The thing is, you never know if a highlighted color is just a little or a lot out of gamut. Gamut Warning is therefore a fairly blunt instrument to work with, which is why I suggest you use the soft proofing method described here.
Print from the proof settings
The Customize Proof Condition is also important because when it is active and applied to an image, the Photoshop Print dialog can reference the soft proofed view as the source space. This means you can use the Customize Proof Condition to select a CMYK output space and the Photoshop Print dialog allows you to make a simulated print using this proof space.
Soft proof before printing
Color management can do a fairly good job of translating the colors from one space to another, but for all the precision of measured targets and profile conversions, it is still essentially a dumb process. When it comes to printing, color management can usually get you fairly close, but it won't be able to interpret every single color or make aesthetic judgements about which colors are important and which are not, plus some colors you see on the computer display simply can't be reproduced in print. This is where soft proofing can help. If you use the Customize Proof Condition dialog as described here, you can simulate pretty accurately on the display how the print will look when printed. Soft proofing shows you which colors are going to be clipped and also allows you to see in advance the difference between selecting a Perceptual or Relative Colorimetric rendering intent. All you have to do is to select the correct profile for the printer/paper