Sharpen for web – A simple introduction

Twilight at St Mary’s Lighthouse, Image without any sharpening applied.


Many people have asked how my images look so sharp, here you will find a simple tutorial that will provide you with tack sharp images when viewed on monitors (the web). While this technique will work very well on most images including slightly out focus ones, there is no substitute for for excellent optics and excellent technique is paramount to produce sharp images. This sharpening walk-through should be followed only at the end of your work-flow i:e after all other colour, curves, etc adjustments are complete and you’re happy with the look of your finished image.


1. With your image open in Photoshop, hold CTRL + J to create a new layer, double click the layer name and name it Pre Sharpen.


2. Now go to VIEW > ACTUAL PIXELS.


3. Go to FILTER > SHARPEN > UNSHARP MASK and enter the following settings. Amount 200, Radius 0.3, Threshold 0 and set the layer mode to Luminosity.


4. Now double click the empty space on the layer, a new dialog box will appear, at the bottom of the box under ‘blend if’ there are 2 bars, on the top bar, drag the black triangle on the left to 20 then hold ALT and drag the same triangle to around 50. Now drag the right triangle to 220 then hold ALT and drag the same triangle to around 180. Repeat this process on the bottom bar making sure to match the numbers on the top and click ok. This tells Photoshop not to sharpen the areas with little detail in the shadows and highlights and prevents nasty artifacts appearing as Photoshop will try and sharpen areas with little or no detail.



5. Now go to IMAGE > IMAGE SIZE and make sure the constrain proportions and re-sample image check boxes are selected and change the re-sampling method to Bicubic. Now change the pixel dimensions of the longest side of the image (this is usually height if the image was taken in portrait orientation or length if taken in landscape orientation) to 1400 pixels (we will go into detail later on why these dimensions) and click ok.


6. Now go to FILTER > SHARPEN > UNSHARP MASK and enter the following settings. Amount 250, Radius 0.3, Threshold 5. Now go to FILTER > UNSHARP MASK and click ok (we have now done this twice).

7. Next we will resize the image to 650 pixels for Internet use. Go to IMAGE > IMAGE SIZE and change the longest dimension to 650 pixels and click ok.

8. We will give the image a final sharpen before saving the final image for uploading to your Website. Go to FILTER > SHARPEN > SMART SHARPEN and enter the following settings. Amount 70, Radius 0.2, remove lens blur and select more accurate and click ok.

9. Should you find the sharpening a little too heavy you can now change the opacity of the ‘Pre Sharpen layer’ to suit, once done flatten and save your image.

The final image after using the technique above.


Closing Thoughts

The method above is only one of many ways to sharpen your images for web and while this works very well for the combination of equipment I use, you may need to tinker with the settings above to arrive at an image your happy with. The quality of your equipment plays a much more important role than the sharpening technique used and therefore I suggest you test all newly purchased equipment to make sure they are performing as they should (links provided for testing equipment found below). There are lots of factors, some of which need a whole tutorial alone to describe in detail how each effect final image quality such as the low pass filter used in each camera, quality of lenses, diffraction and hyperfocal distances used for your particular setup all play an important role in producing suitably sharp images.


Links and further reading

An alternative reading about the use of hyperfocal distance – Depth of field revisited

Sean McHugh has some interesting articles and photography techniques – Photography techniques

Michael Reichmann’s overview of tilt shift lenses – An in use report of the Nikon 24mm PC-E tilt shift lens

David Summerhayes explains how to focus a tilt shift lense – Focusing a tilt shift lens

Sean McHugh explains diffraction – Diffraction

Testing new Equipment – Getting the sharpness you paid for