My friend Gabe just took an assignment photographing jewellery for an auctioneer and we've been talking a lot about lighting. One technique that I really like for sharpening edged subjects, like jewellery is to use High Pass filtering in Photoshop.
- Open the image in Photoshop. I'm using CS6 but high pass sharpening has been around for a while.
- Convert the background layer to a Smart Object. This is a critical step in case you want to make changes after the fact
- Choose Filter | Other | High Pass
- In the dialog box that appears slide the controller to some level of sharpening balancing sharpness with haloing, click ok
- This creates a Smart Filter mask that you can alter after the fact. Right click on the High Pass filter and change the blending mode. Because the filter's transparent space is grey, using any of the blend modes in the Overlay group, will make the grey parts of the filter transparent. Overlay adds a fair bit of contrast, Soft Light is less "edgy" but for jewellery, I tend to prefer Overlay
- Because this is a smart filter, you can always click on the filter and change the pixel settings in real world view to alter the amount of sharpening to taste. Zoom in on the image, then right click the High Pass filter and Edit Smart Filter. Now move the slider to set the sharpening to suit the image
- This last step is often missed and I think it's very important. You probably don't want the entire image to be sharpened, especially backgrounds and other neutral areas. Because you are working with a Smart Filter, this is easy to adjust. Click on the Smart Filter to select it. Set your foreground color to black (this means that you will be masking the effect of the filter) and taking an appropriate sized brush, paint over the areas where you don't want the sharpening to be in effect. To make it easy to see where you've painted use Option-Click (mac) or Alt-Click (windows) to see the mask overlay so you can quickly paint over areas you've missed.
- That's it! Now you have a really nicely sharpened image with a mask to control what part of the image gets sharpened and because it is done with a Smart Filter on a Smart Object, you can always go back and make changes later on.
Credit where credit is due, I learned this technique from the brilliant and talented Julieanne Kost of Adobe.