How to reduce purple color cast in high ISO Nikon D4 and D810 photos

In low-light photos taken with my D4 and D810 I often (but not always) get a severe purple color cast in the dark areas of the photo. I'm going to try posting a link to an example of one such photo, which I've put in my Dropbox account. I hope this works:
Dropbox - Example of magenta color cast-001.jpg
If the link works, you'll see what I mean: the dark areas are purple, not black as they should be. This was taken at the dress rehearsal for a play at ISO 3200, about the lowest ISO that I could get away with. The purple cast seems more pronounced along the edges of the photo.
I've read a bit about "amp glow"; is that what I'm seeing here? If it is, what can I do about it? Turning the camera off and on again and again to try to cool the sensor and the nearby electronics isn't much of an option.
And whether it's "amp glow" or something else, is there a good way to deal with it in Lightroom? I've had some success with reducing the purple saturation (and sometimes the purple luminance as well) in the "HSL" panel, but that becomes a problem if there are important elements in the photo which are SUPPOSED to be purple.
Any and all advice would be welcome.

dorffersmatt wrote:
Interestingly, my e-mail says there was another post about how to reduce the purple cast with proper in-camera settings, but now that post seems to have been deleted (by the poster? by somebody at Adobe?)
The poster (Drugstore) may have deleted the post after reading further because it may not have been relevant......just a guess. If you're shooting raw format the in-camera settings such as white balance are not applied to the image file, but they are for JPEGs. The suggestions I provided are applicable to both JPEG and raw image files, but you'll get the best results using raw format.
dorffersmatt wrote:
1) You said that you sometimes see the purple cast with your D4 and D810 if the white balance isn't set properly. What would you consider a proper white balance setting for a situation such as this one? It was the dress rehearsal for a play, with constantly shifting lighting. I just left the white balance on "Auto"; how would you have approached the situation?
Again, this only applies to JPEG format image files. For raw image files the WB EXIF data is read and set accordingly inside LR. For JPEGs the image data has the (incorrect?) WB applied in-camera, which compromises the dynamic range of the JPEG 8-bit/color data. Raw files are 16 bit/color.
dorffersmatt wrote:
2) You said that you also sometimes see it if "you activate the lens correction in LR while in raw mode and exposure is too low." Could you elaborate on that? Do you mean that I shouldn't use "Enable profile corrections" in the "Lens Corrections" panel?
I'm guessing this refers to what you call "amp glow" (amplifier glow). It usually appears as a higher exposure level around the edge of the image and may be confined to one area (top, bottom, sides). By turning off Lens Profile corrections ( "Enable profile corrections") Vignetting correction is not applied, which reduces the exposure level in the corners and frame edges. Some cameras automatically apply distortion and/or vignetting correction in-camera when shooting in JPEG format. Again, this is just another reason why you want to use raw format to get the best results inside LR.

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Someone here has suggested to take the content of Photostream and create a new Album ( eg: "From Photostream_ Date"),
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3/ when is the best time, to save the My Photostream
Sorry , if too many Q's

My Qs were more specific
It is easier to answer specific question, when I know whch options you are having on your computers. I.e. I wondered if you would be able to use Shared PhotoStreams instead of My Photo Stream, but that would require MacOS X 10.9. at least, see: iCloud: Using and troubleshooting Shared Photo Streams
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That is exactly, why I asked for your system versions: if you could create Shared Streams, you could use 100 separate streams just like albums, and all would be stored in iCloud.
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as also via iCloud (?)
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Some Links:
iCloud: My Photo Stream troubleshooting
iCloud: Photo Stream FAQ
Regards
Léonie
A remark about Photostream : its deletion logic for pics, once 1000 is reached is intransparent
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Why is my black and white video showing purple/green color cast from ProRes 422 h264?

When transcoding from ProRes 422 to h264 in Adobe Media Encoder, I'm seeing both green and purple color cast on my black and white video. ProRes on top, h264 on bottom.
https://www.dropbox.com/s/dqzkkje3ccgravb/Screenshot%202013-10-28%2013.33.27.png
Another example:
https://www.dropbox.com/s/5e1qyhmycgwbpkt/Screenshot%202013-10-28%2014.14.36.png

What do you make of the fact that the same video, encoded in MPEG Streamclip does not have the issue on the same hardware, played in Quicktime Player?
A valid data point for consideration, but the only way to know with certainty is to get the image onto a calibrated TV.
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E-pl1 yellow/green colour blotches at high iso

Hello to all members and Adobe Team.
i use lightroom 3.3 and i have made a comparison between my 2 cameras with the same sensor , e-p1 and e-pl1 and e-p1, and while they have identical grain like pattern and rendering at high iso (which is what i was expecting since they have the same sensor and only the Anti-Aliasing filter is lighter in e-pl1), colour rendering at high iso is very different (at low iso its different but i have profiles with colorchecker and the differences are minor).
So i will post raw files in tungsten lighting (the most demanding for high iso-.-- 1600 i mean and even at 800 i can clearly see the problems i am describing).
Olympus e-pL1 white balance is really, but really bad.. everything turns green (its really bothering to adjust and affects low iso images too... i spent so much time correcting the green cast but there is something that i can never get right).
There are green/yellow/orange and purple/blue blotches at high iso.... it happens in tungsten lighting and fluorescent (less so at fluorescent, but still), those green/yellow blotches appear in uniform color areas that are in shadows its like a tint and there is nothing of this sort in e-p1 at iso1600 and even much higher isos have this kind of noise well distributed by all colour channels (they are usually small blotches/spots a little to the irregular round shap but sometimes have big size and very irregular shape).
I believe its something in the blue channel but in the green channel also!
Reds and colours at high iso are much more saturated in e-pl1 than in e-p1 (and from imaging-resource samples and dpreview e-pl1 its one of the cameras which has more saturated colours at high iso which sometimes it looks they are clipping channels).
By the way this is not something just related to these testfiles it happens in almost all high iso files i believe different colour rendereing/demosaic would do much better.
Here are the raw files, the first one is Olympus e-pl1:
http://hotfile.com/dl/117408120/41b0f01/P5109784.ORF.html
The second one is Olympus e-p1:
http://hotfile.com/dl/117408591/5eab708/P5107466.ORF.html
Notice in the blue trip Samsonite bag there are much more blue blotches with the chroma noise slider at 0 (even at 25 there is a difference in Dynamic range between e-p1 and e-pl1, when all review sites clearly say that e-pl1 is a little better at high iso even in raw, and its not just because it has more detail that you can use to kill a little grain and make things equal).
Please dont post or use this photos as examples as they are not flattering... they are just for Adobe engineers or private testing by users not for posting in other forums.
So Olympus cameras and Panasonic camera sensors all exibiht this problem but i have never seen something like this.... the cameras are quite good at iso1600 except all shadows have that tint even with chroma noise sliders at 40 they never disappear ... is it possible to solve the colour demosaicing and left intact the luminance one?
Please be kind to m43 cameras since they are selling very well and i think they dont have proper support... ( i bet if this was a problem with Canon or Nikon it would be corrected in a time... we dont have coustum profiles but there is a solution for that... although for this problem we dont have better solution since its too selective and only in shadows).
By the way in Rawtherapee i have made adjustments in channel mixer (the levels of green that the blue channel has are very high; so i took a little green (and just a tiny bit of red) and the shadow areas start getting rid of the green dots, so here it is a HINT) and there were many improvements almost making them disappear... however i want to use lightroom not rawtherapee with AMAZE demosaicing.
Oh by the way look at Rawtherapee way of removing colour moiré with AMAze algorithm its fantastic it gives you detail back and no colour moire which shows a lot with e-pl1 in lightroom (but i know its because of lighter AA filter and its not a priority).
Thanks for your help!

Well if you search in the middle of the image you will see at 100% that the open bag has those green spots where it should be gray! and near the door at bottom left of the image you will see those green spots that are very distracting because they happen in shadow areas... (and by the way the red cloth is not the same red as the e-p1 image and its noticeable even at small size).
What white balance did you use?
I know these are just test shots but they appear in people shots too..
Im going to prove that ACR interpretation of olympus auto white balance in olympus e-pl1 is just horrenduos with this raw file (by the way i use this one since its one of the ones with less publicity and with the most straight forward uploading, if you know one that is better to upload tell me please).
http://hotfile.com/dl/117520711/fceaefb/P4248867.ORF.html
Now try white balance at 2850 and tint at 0 (things improve).
Now look at the clock.. it has a contour with the wall that is green/yellow its that kind of problem (i have noise reduction in teh color at 50 and in the detail at 25 to try to mitigate its effect but still not much luck).
Next i will go to the HSL tools in lightroom and select yellow color and select saturation tab and dial in -30 for yellow and voilá! it has reached the kind of performance that i see with e-p1 (a little worse but almost unnoticeable),.. adobe should correct this problem in lightroom 3.5 please.
then i used the split toning slider and in the shadows i dial in hue at 340 and saturation at 10 and there was a bigger reduction in the yellow spots so its the default rendering that is a mess (by the way sometimes if i reduce saturation in the green and in the blue channel it helps a little too like -30 in each) so try to correct these please, if possible by not dessaturate the channels but with an algorithm that detects only those kinds of spots and not all yellow info like you do in the red channel so well!!
Thanks

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In FCP, go to the menu Final Cut Pro > System Settings and click on the Playback Control Tab.
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Also, to add to my misdemeanours, I previously posted the following (slightly amended here) in the LR forum - which again may be not the ideal place.
"I have been really impressed with the camera profiles - in my case the Standard NEF for a D3 - and posted a complimentary message to that effect on the Labs LR beta2 forum under the pseudonym Rockshead.
The revelation that each profile is camera specific raises a particular question about that for the D3. Whilst the conversions at 'normal' ISO ratings are - as I said - stunning; the same cannot be said of those for the very high ISO numbers available with the D3; compared to the conversion of the same in View/CaptureNX. Applying LR noise reduction - by the bucket load - cerrtainly aids the definition, but has little effect on the colour differences.
I suppose my question is, is this something that we have to live with; or is there hope for the future that this will be able to be sorted by further tweak of the profiles. I can quite understand if this is element of the conversion is another ingredient of Nikon's secret sauce, and therefore outside of Adobe's future thinking? Nevertheless, it would be interesting to know the thinking.
Let me hasten to say, I am content to live with it for the relatively few ultra high ISO pictures I deal with. No complaints at all from me on the brilliant way Adobe has tackled the camera profile upgrade. Nevertheless, regular use of high ISOs is coming, and so it is a legitimate question,"

> Whilst the conversions at 'normal' ISO ratings are - as I said - stunning; the same cannot be said of those for the very high ISO numbers available with the D3; compared to the conversion of the same in View/CaptureNX. Applying LR noise reduction - by the bucket load - cerrtainly aids the definition, but has little effect on the colour differences
1. Can if you can provide a documentation for such color differences in form of a raw file and pointing out some differences caused by the conversion?
2. "Very high ISO numbers" is not very specific. I wonder if you are aware of the fact, that your camera's highest real ISO setting is 6400. The settings 12800 and 25600 are eye-wash, meant only for those creating JPEG in-camera.

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I just posted this article about how to recover a dark picture with a heavy
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http://www.braintrove.com/article/58
Greg Collins
Microsoft MVP
Visit Braintrove at http://www.braintrove.com

None taken. I am unfamiliar with ACR and would love to see (compare) what it
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The results I achieved in the article took only a few minutes to
complete--though as I mention below, it took more than a few minutes to get
to the point where I could do it in a few minutes.
I happened across a web site one day discussing the techniques in Margulis'
LAB Color book, which interested me enough to purchase it. I found the book
very enlightening and have seen incredible results using the techniques he
describes as applied to my various images. I've also ready his Professional
Photoshop book which focuses more on CMYK, and found many techniques in
there just as enlightening.
Ultimately the tools and techniques used are irrelevant if you get the
results you want... but if you find one that works faster, easier or better,
then certainly you should employ it.
I have no problem working in RGB, CMYK or LAB and find benefits from each.
The particular sample image I used in the article was one that I've spent
(too much) time cleaning up in various ways and in various color spaces (or
combinations thereof). It became my "poster child" image to work on as I
continue to build my Photoshop skills. The approach I used in the article
was the one I found most to be the fasted with the most effective results.
The original was a 6MP JPG file. I reduced it to the size in the article and
then worked on that size for the remaineder of the article. The resutls are
equivelant in the fullsize file.
Greg Collins
Microsoft MVP
Visit Braintrove at http://www.braintrove.com

How to reduce number of colors in an image

I am fairly new to Photoshop and I'm learning as I go, so I apologize for using your time. I haven't worked with images that much - I've used MS Digital Image Suite with photos from my camera. That's the extent of my knowledge.
I am taking over a job from someone who is gone and I can't ask him how to do this. He used Photoshop to reduce the number of colors in an image (for example, a color drawing or clipart) to 2-6 colors. I haven't been able to figure this out. I've visited this site that explains how to reduce tones but it's still a lot of colors. I thought I might learn something from this link that explained how to make Photoshop cartoons, but I didn't. I've done a lot of searching but nothing seems to explain this. I know that the other guy had some knowledge of Photoshop but he wasn't a power user.
Thanks to anyone who will help me. (I am using CS5.)

Are you sure that he was using Photoshop? (see my third solution)
There are some plug-ins for Photoshop, but they basically do the same as the posterize or index mode: http://www.topazlabs.com/simplify/ (commercial) see this panel for colorizing comic art: http://vimeo.com/user3771002/videos
I would rather use posterize, as an adjustment layer, as you can control it.
Try with this layer stack, from bottom to top:
Convert the original image in a Smart Object, in order to use Smart filters and blur the image (Gaussian Blur, or noise>median or blur>smart blur or blur>surface blur could be interesting internatives) would be useful, to make smoother posterized areas.
A dodge/burn layers (a neutral gray layer in overlay mode) to adjust areas using the Dodge/burn tools.
the Posterize Adjustment layer, with very few colors
On top of it, put a gradient map adjustment layer, to control the posterized colors
Vectorizing in Illustrator can also be used to reduce the number of colors. Live Trace: http://help.adobe.com/en_US/illustrator/cs/using/WS714a382cdf7d304e7e07d0100196cbc5f-6229a .html
More on the topic: http://help.adobe.com/en_US/illustrator/cs/using/WS714a382cdf7d304e7e07d0100196cbc5f-622aa .html

How to correct for dual color casts?

It seems that I have a slight warm color cast from the top of my image down and a slight cool color cast from the bottom of my image up. The center area is color neutral. How to I correct for these color casts?
I tried an adjustment layer with linear gradients added of very pale red to transparent to kill the cool in the bottom half and a linear gradient of very pale blue to transparent to kill the warm in the upper half. The color was somewhat neutralized, but now the top and bottom are even darker, more saturated.
I'm thinking I need something like a gradient "photo filter" for Photoshop?
Anyone know the quick way to solve this problem?
Thanks,
J

I just answered my own question: I changed the color of the Dodge Tool to pale Red and took out the cool cast and now I'm going to change the color to a cool color and take out the warm cast.
Sorry.
J

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