Discovering Dust Spots on Your Photos

Dust spots can suck the like right out of your pho­tos. Instead of enjoy­ing the scene or por­trait that you cre­ated, a few dust spots will get your viewer to start look­ing for prob­lems in the image. Most pro­cess­ing tools have a rel­a­tively easy way to deal with dust spots. The prob­lem is find­ing the lit­tle boogers, though.

Some are pretty obvi­ous. Large spots in the sky stand out. Zap those dust spots with a Heal­ing Brush in Pho­to­shop or some equiv­a­lent tool and you’re all set. The prob­lem is that they aren’t always obvi­ous. There are a few dif­fer­ent tech­niques for find­ing dust spots, but none of them seem to be per­fect. Here are some that I use.

How to Reveal Dust Spots

This first tech­nique is one I saw Scott Kelby teach at Pho­to­shop World and it just seems bril­liant in its sim­plic­ity and effec­tive­ness. You open a Curves adjust­ment and twist it to look like a sine wave. Many of the dust spots will sud­denly jump out and scream for atten­tion, as shown below.

You can see an exam­ple of the sine wave curve on the right side of the photo. The dust spots appear as bright dots in the sky. Just remem­ber to make your Heal­ing Brush adjust­ments on the photo layer, not the Curve layer. When you’re done, throw away the Curves adjustment.

I’ve used a Lev­els adjust­ment in a sim­i­lar fash­ion. The idea is to bring the shad­ows and high­lights toward the cen­ter, and then move the mid­tones around to reveal more dust spots.

Pro Con­trast from Nik Soft­ware Color Efex Pro is another good way to reveal dust spots. Take a look at the screen shot below.

Com­pared to the Curves adjust­ment, this fil­ter makes sev­eral more dust spots vis­i­ble in the sky. In fact, con­trast is your best friend when try­ing to draw out those dust spots. If you really want to get dras­tic, go for a stronger type of con­trast, such as Tonal Contrast.

Now you can see that my cam­era is noth­ing more than a filthy beast. There are spots all over the place, hid­ing in the low-​contrast sky. When you first look at the image, it seems like only a hand­ful of dust spots need your atten­tion. Not so, there are hid­den lurk­ers in the sky.

If You Can’t See the Dust Spots, Do They Matter?

Why should you go hunt­ing for dust spots? After all, that Tonal Con­trast is pretty gar­ish on this photo, so why apply it just to find dust spots that you didn’t notice otherwise?

It’s a mat­ter of work­flow. One of the first things I want to do is clean up the image before I start manip­u­lat­ing it. As you start mak­ing more adjust­ments to your photo — par­tic­u­larly those that enhance con­trast — those spots become more preva­lent. Clean­ing them up after you’ve increased the con­trast makes it more likely to add halos and other tell-​tale signs of post pro­cess­ing. If you nail them before adding other adjust­ments, they aren’t quite so notice­able later.

Even after scour­ing my pho­tos, some­times there are a few faint spots that I don’t find until after I’ve posted a photo. That’s my life. Mis­takes fol­low me around, but I like to make the effort to mit­i­gate as many prob­lems as I can. If you can’t get them all, then a nice Soft Focus fil­ter helps smear them out a bit.

Happy dust spotting.