Sharpening in one direction only

There are times where it may become necessary to only sharpen in one direction. What's that you say? Why sharpen in just one direction? How do I do that?

As we discussed in class (and a good reason to sign up for the next class),  chip makers do some crazy things. Regular readers of this blog already know my rants on the CCTV industry. With that in mind, some chips anti-alias in one direction, but not the other (ie. anti-alias the image along the horizontal whilst leaving the vertical alone). It turns out that Photoshop has had the cure to this problem all along. Remember the Custom Filter? Well, it's time to use it again.

Read the linked post before proceeding as it helps to get your mind set around the rules for using this odd yet powerful filter. Then, click Filter>Other>Custom to bring up the Custom Filter dialog box.

A pretty effective setting for sharpening along the horizontal, but leaving the vertical alone is demonstrated below. Remember the rules, the entries should equal the scale.

The same is true for the vertical, leaving the horizontal alone.

Give this one a try and I'll think that you'll see ... it's a pretty effective sharpener for use with those dodgy DVR images we all see. Better yet, you can build an action to run this and save yourself from having to input the numbers each time.

Enjoy.