Purple/Blue Shadows & Highlights

RogersDA · November 20, 2010

Canon 1D MII @ ISO 1000 shooting RAW. Primary lighting was halogen, but there were a few fluorescents thrown in.

Shadows are purple and blue, including some lighter areas. :dunno

CA adjustments in Lightroom are not effective as this goes well-beyond CA.

Help!

pathfinder · November 20, 2010

David, are you using LR 2 or LR3?

I think you might try the lens profile settings in LR3, if you have it.

What lens were you using?

RogersDA · November 20, 2010

Now using 3 - and I have tried various settings for both lens corrections (with the right lens selected or manual) and camera calibration.

EF 85 f/1.2 MII

RogersDA · November 20, 2010

The best I could do with a combination of lens and camera calibration adjustments.

This screen-grab was before noise reduction applied.

pathfinder · November 21, 2010

With the strong back lighting I think I would call this purple fringing. I rarely see this with my lenses ( and I do own and use an EOS 85 f1.2 old version) , but bright backlighting can certainly cause it.

Shay Stephens used to have an action for correcting purple fringing years ago. I found this link by googling - http://forums.dpreview.com/forums/read.asp?forum=1009&message=7071631

Here is what it says +++++++++++++++++++++++++

And for the PSE crowd, as you know, you have to do things manually:
Light Blue PF
1) Create a new hue/saturation/lightness adjustment layer.
2) Select "magentas" in the drop down box
3) Click on a sample of the blue fringe color you want to reduce.
4) set the saturation to -50.
5) click on ok.
Light Purple PF
1) Create a new hue/saturation/lightness adjustment layer.
2) Select "magentas" in the drop down box
3) set the saturation to -50.
4) click on ok.
Dark Blue PF
1) Create a new hue/saturation/lightness adjustment layer.
2) Select "magentas" in the drop down box
3) Click on a sample of the blue fringe color you want to reduce.
4) set the saturation to -50.
5) set the brightness to -50.
6) click on ok.
Dark Purple PF
1) Create a new hue/saturation/lightness adjustment layer.
2) Select "magentas" in the drop down box
3) set the saturation to -50.
4) set the brightness to -50.
5) click on ok.

These actions may affect areas of an image you don't want (like blue clothing, the sky, etc). In that case, just paint black on those areas of the adjustment layers mask to prevent the area painted from being affected.
Standard disclaimers apply, this is not a cure-all for purple fringe, it's goal is to reduce it to usable levels. It wont fix every and all instances of PF. It will not make your hair grow back or pieces of your anatomy to grow bigger.
If you still need more disclaimers, see this:
http://www.chaser.com.au/splash.asp

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I have never tried this so take it for what it is worth....

Here is link which says PF is quick and easy to remove using the HSL tool - http://www.pcworld.idg.com.au/article/75955/removing_purple_fringing/?fp=2&fpid=1585691688

And another from digital-darkroom forum - http://photo.net/digital-darkroom-forum/006JMx

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
"Here is a method that is new as far as I know - I just discovered it this evening. It is useful for removing the highly saturated purple glow that often occurs at the boundaries between very bright and very dark areas on a digital camera, and which does not respond to chromatic aberration correction.

The cure is based on the highly saturated purple color, which almost never occurs in nature. To isolate these areas, convert the image to LAB mode in Photoshop, where the saturated purple corresponds to bright areas in the A channel and dark areas in the B channel.

By doing a Image/Calculations and taking the difference between the A and B channels, loading that difference as a selection, you almost have the perfect selection to isolate the purple areas. Once the selection has been converted to a mask for a new hue/saturation adjustment layer, you need to do a curves adjustment to steepen the contrast in the layer mask so that only the very deeply saturated purple is removed. The effect is further limited by choosing only the purple colors in the hue/saturation layer.

This might sound complicated, but it's really very easy to do. Even better, this recipe can be recorded in an action that seems to work nearly perfectly on every image I have tried it on.

If you want to try it, I copied my action into a set you can download.

This was recorded in Photoshop CS3 - I don't know which other versions it might work in, but here it is:

Link pulled by mod.

Once you have downloaded this,(just paste the url into your browser) just go to the actions pallete, and choose "Load Actions"

Thereafter, you can run this action on any single-layered image, or even as a batch on a whole folder of images.

If this does not pretty much completely eliminate the purple, you might need to play with the color range in the Hue/Saturation layer that I created. I created this to work with my Canon DSLR's & it's anyone's guess if it works as well for other brands/models. The easiest way to play with this, is to uncheck the last step in the action before running it. Then the Hue/Saturation layer and the mask will be intact, and you can play around with the slider on the "Magentas" adjustment until the fringe is gone.

Also, the final step converts back from LAB to the ProPhoto color space, which is my normal working colorspace. You might want to delete this step and record a new step that converts to your own normal color space instead (and choose "flatten" as the option).

Good luck!"

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I do not think your problem is chromatic aberration, so much, as sensor blooming from the bright blue of the out door light.

pathfinder · November 21, 2010

Nicole Young has a very nice video here - http://vimeo.com/3069865 - that clearly shows a very easy way to correct color fringing in Photoshop. She desaturates the purple fringe, and then uses a layer mask to keep the desaturation of the blue-purple to only those very small areas that need the desaturation. This looks like the trick if you have Photoshop. I have not seen a method for LR yet.

RogersDA · November 21, 2010

Darn - I had forgotten all about Shay's purple fringe action. Let me read through all of that and the other stuff, too. Tomorrow. I'm too tired for this now.

Thanks.

pathfinder · November 21, 2010

I think Nicole Young's video in my second post, is the easiest to follow and perform. Once you have done it, you can create your own action I believe.

RogersDA · November 21, 2010

pathfinder wrote: »

I think Nicole Young's video in my second post, is the easiest to follow and perform. Once you have done it, you can create your own action I believe.

That seems to help a lot. Thanks for the video link.

divamum · December 2, 2010

PF-

Are there issues with your webhost at the moment? I clicked on your link above (http://naturalportraits.com/purple_fringe.atn) and got a "gatorhost exepriencing difficulties" message.

Just wondering...

pathfinder · December 2, 2010

Not my webhost, but a link on the web, Diva, found via google.

I got that message too.. I alway hesitate to suggest sites for PS actions, because I always worry about supposedly free stuff on the web. I did get to the link when I posted that, but I have pulled it for now.

divamum · December 2, 2010

Ah, sorry - I thought that was an action you had made. Back to making my own!

Purple/Blue Shadows & Highlights

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