How do I remove hot pixels in Aperture?

I shoot with a Canon 550D and when I do very long exposures, such as star trails, I get quite a few hot pixels in my images. I've tried almost every single adjustment slider to remove them but I haven't been successful. The color adjustment tool won't even pick up the correct hue when I hover over a bright red pixel in a dark blue sky. Is there anything I can do inside Aperture?

Thanks,
Morten

by PhotoJoseph

July 29, 2011 - 4:16am

Morten,

Hey buddy. How long are your exposures? Digital sensors tend to overheat quickly, which is why the longest fixed setting is 30 seconds on most (if not all) dSLRs.

Anyway, the best way I’ve fond to kill hot or stuck pixels is to use the healing brush. Zoom into the image beyond 100%, and make the brush as small as possible (start with 1 pixel), and click on it. If that isn’t enough, undo, and try one pixel bigger on the brush size. Leave feathering at full.

The good news is, these stuck pixels should all be in the same place in all the photos, so once you’ve fixed one picture, you can lift/stamp the healing to the rest of ‘em.

-Joseph @ApertureExpert

@PhotoJoseph
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by Morten Scheel

July 30, 2011 - 8:59pm

Thanks Joseph,
The photo that made me post this question is this star trail shot I made recently (23 minutes exposure): https://plus.google.com/112504701234237545735/posts/9PZ2264cTLL

I removed 4 or 5 bright hot pixels (pure red) that were visible at 1920x1200 resolution using the healing brush, but at 100% zoom there are thousands of slightly dimmer red pixels (blown up version here: http://dl.dropbox.com/u/2304104/Screenshots/starnoise.jpg). They don’t move with the stars so I’m assuming they’re also a camera artifact. Are these tiny “wrong” pixels also “hot” or could they be some sort of color noise?

Sorry, one last question: Are very long exposures like 20+ minutes damaging to the sensor in the long run?

Thanks again Joseph!

by PhotoJoseph

July 30, 2011 - 11:49pm

Morten,

That’s chromatic aberration. Try the Chromatic Aberration adjustment, as well as the Halo Reduction brush.

-Joseph @ApertureExpert

@PhotoJoseph
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