Colour Fringing Explained

[Suhit Gupta]

<div class='os_post_top_link'><a href='http://www.photoreview.com.au/Article.aspx?aid=ff89a68a-2a67-4543-9bd0-6626e610deaf' target='_blank'>http://www.photoreview.com.au/Article.aspx?aid=ff89a68a-2a67-4543-9bd0-6626e610deaf</a><br /><br /></div><i>"Expect to hear a lot more about colour fringing in digital photos as the pixel counts for compact digicams continue to rise, while sensors become smaller. At the same time, expect to see the true reasons for colour fringing misattributed more often than not. To ‘put you in the picture’ (so to speak), if you see coloured fringes along edges in a photograph it can be attributed to one of two effects: chromatic aberration or blooming. The problem is deciding which one is the cause. If the picture was captured on film, deciding what caused the coloured fringing is easy: only chromatic aberration can be blamed. It’s more difficult if the shot was taken with a digital camera because both blooming and chromatic aberration can create coloured fringes. Teasing out which one is relatively easy once you understand how the fringes are produced."</i><br /><br />Interesting article, it explains chromatic aberration and blooming. It also talks about a couple of software applications that are available for removing coloured fringes from digital pictures.

[Lee Yuan Sheng]

Photoshop CS RAW has a few options for playing with that, I think. Panaroma Factory (Tools? I forget the title) also has a way of dealing with chromatic aberrations, but you'll need the "coefficients" (can't remember the exact term) to deal with that.

To add, chromatic aberrations are still fairly common, since low dispersion glass isn't exactly cheap, and the best way of deploying them is usually the most expensive, by the way of placing them in the front elements (where the glass element is the largest). Most people don't spot chromatic aberrations though; they spot the purple/blue fringing that pops up in most digitals.