Using Photoshop’s High Pass Filter to Sharpen a Soft (Fuzzy) Image

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The two images below are of Mother’s (Marion Gunderson) watercolor supplies. These images are derived from the same original. There is one difference between the two photos. Using Adobe Photoshop* editing software, the top photo has had the High Pass filter applied; the bottom photo has not. The High Pass filter helps to sharpen a photo that is just a tad soft/fuzzy.

I think it is difficult to isolate differences between these two images unless you enlarge them and look very closely. That’s probably good, since if any difference was blatant, that might mean one was over-edited and didn’t look natural. However, I think the top one looks a little bit sharper than the bottom one as a result of applying the High Pass filter.

Before I learned about the High Pass filter, I tried applying Photoshop’s Sharpen filter but didn’t think the results were worth the edit. (Maybe part of it was because I didn’t really know what I was doing.) Then I ran across Duane’s (at Christian Photo) explanation of when and how to use Photoshop’s High Pass filter to sharpen photos. Here are Duane’s illustrated instructions. More thorough instructions of how to use the High Pass filter are at this YouTube 6-minute video. Another explanation (my least favorite but still helpful) of the High Pass filter mentions a step of adjusting the hue/saturation so as to avoid color fringing.

I know there are varying opinions about editing photos. Most definitely, every time an image is resaved as a JPEG, some image information is lost. However, if an image is edited in PhotoShop, and resaved as the same PhotoShop file keeping the edit history in tact, my understanding is that information is not lost.

Of course, the ultimate goal is to get the perfect shot and not have to do any editing. When that doesn’t happen, I’m thankful for Photoshop.

The High Pass filter was applied to this photo of Mother's watercolor supplies. I believe the High Pass radius I used was around 2.0. If I were to do it again, maybe I would use a higher radius number.

At a glance, it was difficult for me to isolate any differences between these two images. Even so, I think the top one looks sharper. One area I see that difference is in the area of bright yellow paint in the middle of the images. When I click on each photo to enlarge it, I see that in the top photo (with the High Pass filter applied) the tiny dark dimples are more crisp “dots” than in the bottom photo.

In this image, the High Pass filter was not applied.

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*My Adobe PhotoShop version is CS4 Extended.

By the way, in the watercolor-supplies-banner that is seen today at the top of this blog (but sometime will be replaced with a different banner image), the High Pass filter has not been applied.

(Click here to go to Louise Gunderson Shimon’s blog’s home page.)

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