View Full Version : help to get rid of magenta cast


Cyber Cat
06-09-2006, 02:40 PM
hello, .... just came back from puerto rico (picture pirfect place), but not for me :( i know everything depp. on the camera used ,but im not a photographer so i used regular cheap camera (its not even digital), so back to the point ... got back my images and what a shock ...90% of images have magenta cast , no matter what i did to 'em it didnt turn out to be even close to what was happening at the time when photo was taken. according to the images time of shot is around 7 or 8 pm, but in actuallity it was taken around 2 or 3 pm.
sooooo, please help me....
oh, and noise allover the image as well.
larger image here: http://cherrydust.com/Luquillo_beach.jpg

thank youuuuuuuuuuuuuu

philbach
06-09-2006, 02:51 PM
Well I switched the photo over to lab and then used the color sampler in photoshop to sample the clouds and decided they were gray with no cast. So using curves on the a and b channels I adjusted the color of the clouds to neutral.

I don't know if this what you saw at the time but that is how I corrected or at least changed your photo.

Cyber Cat
06-09-2006, 03:39 PM
Dear Phil, thank you, looks amazing.
off to follow your steps

Daviskw
06-09-2006, 03:56 PM
Hi there

I color corrected then added a little color to the sand and replaced the sky

Butch

JuliPhotography
06-09-2006, 08:14 PM
Phil,
May I ask why you chose to color correct with lab color instead of RGB. The image looks a lot better.
Thanks.

byRo
06-09-2006, 08:33 PM
Normally auto-levels will give you a good start when fixing a photo like this. However if you try that nothing happens. :(
Auto-levels works by fixing the extreme points. If you look at the left edge there's a white border and so Auto-Levels will fix that and not even see your photo.

- I put in a Levels layer and selected the grey point on the sand. That left things still slightly blue so, still in Levels, I nudged the Blue gamma slider to taste;
- The image seemed to need a bit more colour, so I put in a Hue/Saturation layer and increased the Saturation a touch (+30%);
- A look at the Histogram shows the photo with lots of Highlights, some Shadows and hardly any mid-tones. A quick fix here is to duplicate the layer and run Image>Adjustments>Equalize, back off the opacity until you get a good result;
- Still seemed to be lacking colour, but increasing the saturation more resulted in harsh blues and yellows. So changed to LAB mode and with a Curve tweaked the mid-part (only) of the B curve.

Took a lot longer to write than to do!


byRo
06-09-2006, 08:46 PM
Phil,
May I ask why you chose to color correct with lab color instead of RGB. The image looks a lot better.
Thanks.
Hi there Juli, welcome to RetouchPRO. :bigthmb:

Hope Phil doesn't mind if I reply...

Without going into too many details: In LAB the Lightness information (greyscale image) is in a separate channel to the colour information (which is in A and B). This means that any adjustments that you do to the colours, won't affect the Lightness.

In RGB things are different. The Lightness is a mix of the information in all three channels, and perceived colour is another mix of the three. Which means that if you adjust the colour, chances are that the Lightness will get ..er.. mixed up.

So that's why, in general, LAB is a good option for doing colour adjustments.


mistermonday
06-09-2006, 09:44 PM
Hi Cybercat, I get so many of these types of images that I have tried to come up with some techniques / actions that work well on a range of similar images that I can save a lot of time and batch them. This image happened to work quite well.
The sequence was as follows:
Equalize the image first (Image>Adjust>Equalize)
Do a Shadow Highlight Adj (Image>Adjust>Shadow Highlight) Default values 50/50/30.
This next step is not always necessary but often with underexposed images there is a lot of noise, so at this point I run Noise Ninja to smooth out the noise before the las step.
Next Image>Adjust>Match Color and just check the Neutralize box with no other settings.
The image come pretty well back into range for me. As a final tweak I took the image into LAB and did a minor curve adjustment to reduce the magenta by a few points (A channel) and increased the yellow by a couple (B channel).
Regards, Murray

Cyber Cat
06-10-2006, 11:24 AM
:bow: philbach, Daviskw, byRo, mistermonday i cant thank you enough for helping me. now with your guidance i can try to save rest of the images.

Dallas_TX
06-10-2006, 12:19 PM
a simple no-nonsense approach. (http://raymondshay.com/tutorials/PhotoEditing101/)


Really funny author too.

philbach
06-10-2006, 01:13 PM
Phil,
May I ask why you chose to color correct with lab color instead of RGB. The image looks a lot better.
Thanks.
Juli, Ro answered the question. And no I am not offended, Ro. Thanks for helping.

JuliPhotography
06-10-2006, 04:38 PM
Thanks for answering my question. I used LAB in an image that I was trying to color correct w/ RBG and was having trouble w/ the highlights becoming blown out. Color correcting it w/ LAB helped a lot. I wish I had known that earlier... there seems to be sooooo much to learn.
Thanks for your help!

cspringer
06-10-2006, 11:46 PM
Looks like the others but used an action. I love 1 click solutions when they work...

average blur/inverted layer at 50%/Color mode.
Hue/Sat. adjustment layer at 50% Saturation/Normal mode.
add a levels or curves adjustment layer.

You can always tweak it more by Ctrl+U the average blur layer.

Ctrl+Shift+B gets you to the same place too (auto color).

After running the action I used the Paint With Light I action at www.atncentral.com and more Hue/Sat.

Photo678
06-11-2006, 02:57 AM
selective color>magenta channel....remove magenta>white channel...remove magenta.....color balance...add green, add red, remove blue

Cameraken
06-11-2006, 05:08 AM
Hi Cyber Cat.

I used my ‘Color Cast Remover’ Filter

http://www.filterforge.com/filters/384.html

To remove the magenta cast and then used Replace colour and Hue/Sat to boost the colours. A bit of colouring, Neat Image and sharpened.

Ken.

philbach
06-11-2006, 10:50 AM
This technique was mentioned in an earlier post and Doug and Swampy who contributed this information.

Open the file in photoshop
Copy the Layer
On the Copied Layer apply Filter/Blur/Average
Invert the color in the copied layer
Change blending mode of the copied layer to overlay.

If you have a zillion photos and if this works for you, you can set up an action to batch all of them.

manta1900
06-22-2006, 09:53 AM
Keep it simple...

slipchuck
06-22-2006, 12:26 PM
I tried to keep it as close as possible to what image the original scene to be...
curves with the eye dropper method.
found the grey, white, black etc.
I was tempted to add some saturation but felt it would look natural.


cheers