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Author Topic: D800 clipping red channel ? Any possible solutions  (Read 8024 times)
Lorenzo Pierucci
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« on: February 03, 2014, 01:34:33 AM »
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Hi everybody Smiley

I just come across on the net what seems to be the cause of my mayor "dislike" of my D800: skin rendering. Looks like the D800 have a certain tendency to blow up the red channel pretty quickly.

Many time when i shoot in studio i had perfectly expose ( exposimeter on my hand ) shoots, that produce burned skin tones. Also when i use it as day by day camera, shooting family and friends, the skin always turn in a yellow no detail tone, if i expose for the scene. There is no compare to Portra 400 or my Leaf DB.

So i start look around, and i saw some wedding photographer that achieve pretty nice skin tones with my same camera... But still some complain about this D800 blowing red channel.
I had a 5D II for years and i never had such problem, also seems that many big studio photographer are shooting with 5Ds ( as far i can see from back stage of Testino and Leibovitz ) when they don't use their Phaseone or Hassy backs.

I played with those files on C1, Craw and LR a lot, but there is not a fix workflow so far to me, as shoot portra with a 81A and expose for shadows Smiley

Anyone had similar experience or even better willing to share solutions?

Thanks to everyone that put time on this
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BartvanderWolf
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« Reply #1 on: February 03, 2014, 02:22:39 AM »
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I just come across on the net what seems to be the cause of my mayor "dislike" of my D800: skin rendering. Looks like the D800 have a certain tendency to blow up the red channel pretty quickly.

Hi Lorenzo,

The question is, is the Red channel really blown in the Raw data, or does it get clipped after White-balancing? Most Raw converters only show a histogram of the RGB channels after demosaicing and White-balancing, so that won't help to find the cause. A Raw converter like RawTherapee does allow to switch the histogram to show Raw data, and it allows to remedy an issue like White-balance induced clipping. For Raw data analysis you can also use RawDigger.

Once you know whether the Red channel is really clipped, you can take precautionary measures that reduce the Red channel exposure level (cooler lightsource, filter, reduce overall exposure). If the Red channel is not clipped, then it is probably an imbalance in the Red channel sensitivity, perhaps caused by IR. Human skin diffusely reflects IR reasonably well, so the camera should filter it to avoid contamination.

Then it is also possible that it is just a matter of getting a better profile, something you can achieve relatively easy with Capture One Pro, because you can adjust an existing profile in the Color editor (which has some very useful skin correction capabilities) and save that as a new profile.

Cheers,
Bart
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ErikKaffehr
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« Reply #2 on: February 03, 2014, 03:16:41 AM »
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Could you post a raw file showing the problem?

Best regards
Erik


Hi everybody Smiley

I just come across on the net what seems to be the cause of my mayor "dislike" of my D800: skin rendering. Looks like the D800 have a certain tendency to blow up the red channel pretty quickly.

Many time when i shoot in studio i had perfectly expose ( exposimeter on my hand ) shoots, that produce burned skin tones. Also when i use it as day by day camera, shooting family and friends, the skin always turn in a yellow no detail tone, if i expose for the scene. There is no compare to Portra 400 or my Leaf DB.

So i start look around, and i saw some wedding photographer that achieve pretty nice skin tones with my same camera... But still some complain about this D800 blowing red channel.
I had a 5D II for years and i never had such problem, also seems that many big studio photographer are shooting with 5Ds ( as far i can see from back stage of Testino and Leibovitz ) when they don't use their Phaseone or Hassy backs.

I played with those files on C1, Craw and LR a lot, but there is not a fix workflow so far to me, as shoot portra with a 81A and expose for shadows Smiley

Anyone had similar experience or even better willing to share solutions?

Thanks to everyone that put time on this
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Justinr
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« Reply #3 on: February 03, 2014, 10:34:57 AM »
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I find skin tones notoriously difficult with any digital camera and the paler the skin the worse it gets.
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Ellis Vener
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« Reply #4 on: February 03, 2014, 11:10:53 AM »
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Up until the 5d mark III and 1D X I found the Canon DSLRs to have far worse problems with skin tones than Nikon's DSLRs and I've never seen the problem you are encountering with your D800.

First things first: what are you using as lighting?

Are the red channels blown on your camera's histogram ( see http://www.ppmag.com/web-exclusives/2007/12/what-is-a-histogram-and-how-do.html to explain why that might be) or in your raw processing software's histogram?

Are you sure you are not over-exposing? The "Expose To The Right" mantra can be overdone you know.

Have you tried creating a custom camera profile for Lightroom or ACR to use?

I'd really want to see some examples before thinking this is not really a Canon lover's FUD in the guise of a complaint.
« Last Edit: February 03, 2014, 11:16:59 AM by Ellis Vener » Logged

Ellis Vener
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ErikKaffehr
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« Reply #5 on: February 03, 2014, 11:27:53 AM »
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Hi,

There were some discussion on one of the MF-threads recently. I would be much interested to see some raw images with problematic skin tones, to see what it is about.

Personally I shoot Sony and no skin. So I have no samples of my own.

Best regards
Erik


Up until the 5d mark III and 1D X I found the Canon DSLRs to have far worse problems with skin tones than Nikon's DSLRs and I've never seen the problem you are encountering with your D800.

First things first: what are you using as lighting?

Are the red channels blown on your camera's histogram ( see http://www.ppmag.com/web-exclusives/2007/12/what-is-a-histogram-and-how-do.html to explain why that might be) or in your raw processing software's histogram?

Are you sure you are not over-exposing? The "Expose To The Right" mantra can be overdone you know.

Have you tried creating a custom camera profile for Lightroom or ACR to use?

I'd really want to see some examples before thinking this is not really a Canon lover's FUD in the guise of a complaint.
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LKaven
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« Reply #6 on: February 03, 2014, 12:34:05 PM »
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I just come across on the net what seems to be the cause of my mayor "dislike" of my D800: skin rendering. Looks like the D800 have a certain tendency to blow up the red channel pretty quickly.

One important question is what capture parameters are you using.  (This aside from questions about light sources, and other important questions also worth asking.)

If you are using C1, then for best skin tone results, I'd recommend using the "neutral" profile, which is really the linear profile.  First of all, it gives you the unpolluted color as well as the unmodified linear data.

If you use one of the tone curves, you will risk bunching up colors and color transitions, especially in skin tones.  The "standard" profile is the worst offender.  The "portrait" profile was created to mitigate some of these issues, but it also has some problems.  Also, if you use the standard/portrait tone curves, you will lose about .5 to 1 stop in highlight headroom, due to the way the tone curve boosts the highlights.  Some of the overexposure you mention just might be the result of this artificial boosting.
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Some Guy
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« Reply #7 on: February 03, 2014, 05:20:11 PM »
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Red is an easy one to blow out if you over expose it in the Nikon.  Would be nice to see a RAW image you have done to analyze it.

Personally, I process NEF files with Nikon's Capture NX2 since their own processing engine takes all the camera's settings and uses them along with the "Nikon Adobe RGB 4.0" color space.  I'm not fond of other RAW converter's since they do not read the camera's settings as well.  In the camera's menu, I have the Saturation down a notch from normal, and maybe -0.6 as my default exposure as well.  I know the Sharpness is up a lot over the default as Nikon is normally soft there over Canon, but don't recall the Contrast I am using.   Some of this was trial and error using the x-rite ColorChecker and just trying to get the thing's default settings to reproduce that chart without a lot of post processing work in various converters.  Put that red channel too far to the into right on the histogram and it is difficult to pull any detail out of it, hence my tendency to underexpose a bit.  I prefer to call it "Expose for the Red."  Bright red neon-like cloths can be very hard to deal with once over-exposed. I output as TIFF from Capture NX2 also.  Any other post-work gets whatever other program I use past that point.

Fwiw, I get really nice skin tones out of that camera over my older Canon 5DII which seemed to like yellow.  The two companies do seem to have a difference when it comes to skin tone color out of their cameras.  The dynamic range is quite high and you can hold back exposure a bit, just look around for reds in the scene and figure out how much to negative exposure to apply to the default.

SG
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Lorenzo Pierucci
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« Reply #8 on: February 04, 2014, 10:49:46 AM »
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Hi everybody

First of all: i know that this seems a hell of troll post but is not ( that's what a troll will says anyways…. )

I really have this things buzzing me for a while. First was look like that the LCD of the D800 ( mine is one of the first one produced as i bought as soon was come out ) had some color problems, and many seems agree of the yellowish colorcast. Then also when i bring images on the my desktop them looks not correct to me.

My issues is that when shooting outside, normally exposed scene turn to have skin tones usually burned, in order to avoid it, i got to underexpose. If I'm shooting in a studio, skins looks yellowish and hilights area have less details. I might be wrong, and if so feel free to correct me.

Thanks to all the people that share some workflow, I'm tying now all those technique both in C1 and this new ( to me ) Rawtherapee. Im also attaching 2 RAW:

1- is a studio shoot: skin turn out so yellow to me, she had a nice pink russian skin.
https://www.dropbox.com/s/9kbmec1oyc7bf9p/DSC_9837.NEF

2- my "girls" picking up strawberry, i had to turn exposure down a notch to get the skin workable.
https://www.dropbox.com/s/gkk7j2vr3xhdojp/DSC_2102.NEF

What I'm doing wrong? what is the best "recipe" to get a constant output that will look like kodak portra simile?
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Vladimirovich
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« Reply #9 on: February 04, 2014, 11:24:25 AM »
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1- is a studio shoot: skin turn out so yellow to me, she had a nice pink russian skin.
https://www.dropbox.com/s/9kbmec1oyc7bf9p/DSC_9837.NEF

not sure where did you get that "pink russian skin" thing ? are you talking about a girl (not a woman) outside in -10C after running around for a while ?

looks normal to me for an adult trying to watch her weight and sitting inside

http://imageshack.com/a/img838/4672/fs24.jpg

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BartvanderWolf
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« Reply #10 on: February 04, 2014, 12:04:02 PM »
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1- is a studio shoot: skin turn out so yellow to me, she had a nice pink russian skin.
https://www.dropbox.com/s/9kbmec1oyc7bf9p/DSC_9837.NEF

This image is exposed 1.14 stops below clipping of the Green CFA channels, and the Red CFA channel is 2 stops below clipping. So there are no exposure clipping issues to be expected. Skin color looks perfectly normal to me (no jaundice). Camera and lighting quality is fine, no extreme IR contribution beyond design specifications. So if you see a yellow skin, it must be created  after Raw conversion and applying a profile and color balance. Time to check your Raw converter settings and check display calibration.

Quote
2- my "girls" picking up strawberry, i had to turn exposure down a notch to get the skin workable.
https://www.dropbox.com/s/gkk7j2vr3xhdojp/DSC_2102.NEF

The Green CFA channels are 0.22 stops below clipping, so perfectly Exposed-To-The-Right (ETTR), and the Red and Blue CFA channels are below that, so not clipped either. Again, check the Raw converter settings and Display calibration.

Cheers,
Bart
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Lorenzo Pierucci
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« Reply #11 on: February 04, 2014, 12:16:47 PM »
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Thanks guys for the time put on this, and great that images looks good to you.

Ergo => i might facing some display problems….
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ErikKaffehr
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« Reply #12 on: February 04, 2014, 12:23:38 PM »
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Hi,

Thanks for posting the images.

I am no expert on skin tones but both look good to me. I checked both for channel clipping using raw digger and they are OK. My conversions are also well within sRGB so I don't think you have a clipping issue.

Best regards
Erik

Ps. :-) I am not familiar with nice pink russian skin, unfortunately. :-)

Hi everybody

First of all: i know that this seems a hell of troll post but is not ( that's what a troll will says anyways…. )

I really have this things buzzing me for a while. First was look like that the LCD of the D800 ( mine is one of the first one produced as i bought as soon was come out ) had some color problems, and many seems agree of the yellowish colorcast. Then also when i bring images on the my desktop them looks not correct to me.

My issues is that when shooting outside, normally exposed scene turn to have skin tones usually burned, in order to avoid it, i got to underexpose. If I'm shooting in a studio, skins looks yellowish and hilights area have less details. I might be wrong, and if so feel free to correct me.

Thanks to all the people that share some workflow, I'm tying now all those technique both in C1 and this new ( to me ) Rawtherapee. Im also attaching 2 RAW:

1- is a studio shoot: skin turn out so yellow to me, she had a nice pink russian skin.
https://www.dropbox.com/s/9kbmec1oyc7bf9p/DSC_9837.NEF

2- my "girls" picking up strawberry, i had to turn exposure down a notch to get the skin workable.
https://www.dropbox.com/s/gkk7j2vr3xhdojp/DSC_2102.NEF

What I'm doing wrong? what is the best "recipe" to get a constant output that will look like kodak portra simile?

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digitaldog
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« Reply #13 on: February 04, 2014, 12:47:07 PM »
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Ergo => i might facing some display problems….

Perhaps. The image looks fine on this end and in Lightroom follows what I'd consider a good skin tone ratio*

At least with Adobe raw converters, you can get a decent idea of color clipping based on it's histogram (either Melissa RGB or ProPhoto, close enough). The NEF shows nothing close to color or tone clipping, the skin tone values look good as a default starting point.

*
Here's a video on correcting skin tones without having to resort to CMYK using Adobe raw converters:

Low Rez (YouTube)
http://www.youtube.com/watch?v=dWaFDKrNrwc

High Rez
http://digitaldog.net/files/SkinToneVideo.mov
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Some Guy
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« Reply #14 on: February 04, 2014, 12:51:02 PM »
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Couple of things in your NEF files.

One is that you are all over the place in your "Picture Control" settings.  The woman is set for "Monochrome" (??). The girls are set as "Landscape" (Which is far more vivid.).  Also, you might want to pull the red back to the left in the histogram of girls shot by setting using your camera's Active-D lighting set to "Low" in Capture NX2.  This is done using Capture NX2 which you should be using to see what you are doing as you are all over the place in settings.  None of the other RAW processors are going to see this, nor know how to deal with it.  There is a difference and why Nikon recommends their software for initial post work.  I would hope their engineers know a bit more than the other software converter makers, Adobe included.

For fun, I also opened the woman's image in Capture One 6 and it is really saturated on color (and heavy towards an orange) verses Capture NX2 which looks far more natural.  Not a pleasant way to go on initial processing.  Adobe's 8.3 RAW and DxO Optics Pro 9 aren't as heavy on color saturation as CO, but both are warmer and more saturated than Capture NX2 which seems very neutral and natural.  No doubt there could also be an issue with Apple's Colorsync too if you use a Mac which always seems to mess up something or some driver matter with each version.

Aside, I'll agree with the D800 camera's LCD not being all that pleasant to look at over the Canon's LCD screen.  In studio it looked awful on the LCD prior to the last firmware update.  The Canon looked far better side-by-side.  My D800 had a sickly cyan/green color under studio lights, but the images were always good in post.  It looks warmer since the firmware update.  But I don't rely on it for an accurate representation as it cannot do that.  It ain't an Eizo screen!

These were out of the D800E.  The girl's costume is a bright red Shantung satin fabric that has a faint texture. The texture is still there.  Just have to watch exposure and the Active-D lighting control (and utilization in Capture NX2) to keep it there.

http://24.media.tumblr.com/2c8ef2fcbbbd6f7408c296a6e21ee626/tumblr_mp6h4dmzjH1s9g2zzo2_1280.jpg

Her skin coloring, although powdered by a MU person:

http://24.media.tumblr.com/2b3df062647757df7f0ca003f9d11adb/tumblr_mp6gtjvk441s9g2zzo2_1280.jpg

Try and standardize your shooting control (maybe "Normal"), check your camera's exposure to see if it is leaning towards overexposure (All my Nikon's do for some reason so I set a minus value into them.), and use a decent converter that shows you what the camera was set on and doing (i.e. Capture NX2).  Capture NX2 has a new release out today that is further tuning their RAW converter's color balance too.  If you want odd coloration's, use another conversion program.

Interesting learning experience, and made me more apprehensive of using Capture One as well.

SG
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Justinr
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« Reply #15 on: February 04, 2014, 01:30:33 PM »
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Couple of things in your NEF files.

One is that you are all over the place in your "Picture Control" settings.  The woman is set for "Monochrome" (??). The girls are set as "Landscape" (Which is far more vivid.).  Also, you might want to pull the red back to the left in the histogram of girls shot by setting using your camera's Active-D lighting set to "Low" in Capture NX2.  This is done using Capture NX2 which you should be using to see what you are doing as you are all over the place in settings.  None of the other RAW processors are going to see this, nor know how to deal with it.  There is a difference and why Nikon recommends their software for initial post work.  I would hope their engineers know a bit more than the other software converter makers, Adobe included.

For fun, I also opened the woman's image in Capture One 6 and it is really saturated on color (and heavy towards an orange) verses Capture NX2 which looks far more natural.  Not a pleasant way to go on initial processing.  Adobe's 8.3 RAW and DxO Optics Pro 9 aren't as heavy on color saturation as CO, but both are warmer and more saturated than Capture NX2 which seems very neutral and natural.  No doubt there could also be an issue with Apple's Colorsync too if you use a Mac which always seems to mess up something or some driver matter with each version.

Aside, I'll agree with the D800 camera's LCD not being all that pleasant to look at over the Canon's LCD screen.  In studio it looked awful on the LCD prior to the last firmware update.  The Canon looked far better side-by-side.  My D800 had a sickly cyan/green color under studio lights, but the images were always good in post.  It looks warmer since the firmware update.  But I don't rely on it for an accurate representation as it cannot do that.  It ain't an Eizo screen!

These were out of the D800E.  The girl's costume is a bright red Shantung satin fabric that has a faint texture. The texture is still there.  Just have to watch exposure and the Active-D lighting control (and utilization in Capture NX2) to keep it there.

http://24.media.tumblr.com/2c8ef2fcbbbd6f7408c296a6e21ee626/tumblr_mp6h4dmzjH1s9g2zzo2_1280.jpg

Her skin coloring, although powdered by a MU person:

http://24.media.tumblr.com/2b3df062647757df7f0ca003f9d11adb/tumblr_mp6gtjvk441s9g2zzo2_1280.jpg

Try and standardize your shooting control (maybe "Normal"), check your camera's exposure to see if it is leaning towards overexposure (All my Nikon's do for some reason so I set a minus value into them.), and use a decent converter that shows you what the camera was set on and doing (i.e. Capture NX2).  Capture NX2 has a new release out today that is further tuning their RAW converter's color balance too.  If you want odd coloration's, use another conversion program.

Interesting learning experience, and made me more apprehensive of using Capture One as well.

SG


Having seen those two images (esp the first one) it looks as if I'm going to have to stop messing about with freebie convertors and and do a proper job with NX2. Lovely work.
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« Reply #16 on: February 04, 2014, 03:22:51 PM »
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The picture of the woman is actually significantly underexposed. In RT setting it on neutral moves the clipped edge of her fingernail below the 3/4 line on the histogram. Setting Auto levels moves exposure to +1.12

More importantly for your red clipping, the only way I can get it to do that is to set temp to cloudy which moves it to over 6000 kelvin. Then the red clips and she looks orange. If you set your color to camera she has a mild tan. If you set it to AWB she looks more typical for pale far north skin.

You need to fix your settings.
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Vladimirovich
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« Reply #17 on: February 04, 2014, 03:58:45 PM »
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This image is exposed 1.14 stops below clipping of the Green CFA channels
PS: one Iliah Borg does not like moving close to clipping with D800(e), something like not within 1 stop of that...
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LKaven
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« Reply #18 on: February 04, 2014, 06:44:34 PM »
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The picture of the woman is actually significantly underexposed. In RT setting it on neutral moves the clipped edge of her fingernail below the 3/4 line on the histogram. Setting Auto levels moves exposure to +1.12

More importantly for your red clipping, the only way I can get it to do that is to set temp to cloudy which moves it to over 6000 kelvin. Then the red clips and she looks orange. If you set your color to camera she has a mild tan. If you set it to AWB she looks more typical for pale far north skin.

You need to fix your settings.

Again, I suspect the choice of tone curve and profile has something to do with what the OP is getting.  A "standard" curve will not only push the highlights, but make the bunch up a bit.  The "portrait" profile is better in just this one way.  But the "neutral" or "linear" or "camera linear" profile is the only one that tells you what the real exposure was, and will deliver neutral tones.
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Lorenzo Pierucci
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« Reply #19 on: February 05, 2014, 09:37:57 AM »
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Great for this! Thanks so much
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