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barjohn

Skin Colors in LR

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One challenge is that the minimum luminance on the iMacs is very bright. Higher than the calibration want it to be.

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Thinking some more about the apparent inadequacies of the ACR/Lightroom engine.

 

The calibration for the M8 was performed in version 3.6 and obviously has some adjustments that we are not privy to, nor able to adjust - in this timescale there have been several firmware updates and widespread use of the IR cut filters - don't think that these are specified in the metadata of the DNG and not obvious if ACR selects profile depending on M8 menu options. Is it possible to request that Adobe perform another calibration and hopefully make a more accurate profile? Despite the most stirling efforts of members here to optimise settings - I fear that at least one of our hands is tied behind our backs on account of this Adobe 3.6 calibration and that endless variations of Hue/Saturation in each channel will have only limited success.

 

Clearly the sales of M8 have exceeded initial expectations and therefore it commands a market share that is admittedly much smaller than Nikon/Canon, but nevertheless has perhaps a disproportionate number of high profile users who need the best image quality possible.

 

Perhaps those who do use other digital cameras from Nikon/Canon might be able to testify whether it is easier to produce appealing images using ACR/LR? Some of the LR tools are very intuitive and offer creative control - I would prefer to be able to continue working on the DNG instead of a tiff which I have had to export from Capture One to achieve the colour fidelity and look of the image.

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The calibration for the M8 was performed in version 3.6 and obviously has some adjustments that we are not privy to, nor able to adjust - in this timescale there have been several firmware updates and widespread use of the IR cut filters - don't think that these are specified in the metadata of the DNG and not obvious if ACR selects profile depending on M8 menu options

 

Well, thanks to Baxter, I just learned something new:

 

Up till this morning, I would have automatically have responded that ACR and LR read the color matrix in the DNG, and since Leica has modified that post IR filters, ACR/LR's color calibration has changed. But then I thought, I've never actually checked that. So I did, by overriding the color matrix in a test DNG, which should give weird color. And it made no difference. Then I also overrode the camera name to unknown, and then, guess what, weird color, as expected.

 

So bottom line is, even if ACR/LR are reading a DNG, if they see a camera name they recognize, they will use a preset camera raw color calibration, not what's in the DNG. Only if they don't recognize the camera name will they use the DNG values.

 

To confirm this, I took a look inside the LR/ACR code, and "Leica M8 digital Camera" is indeed listed in there.

 

Sandy

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Hi Sandy,

 

I am glad it is not just me and thanks for looking under the bonnet in the code to confirm my empirical observations. Having given the matter some thought, I decided to go to the horse's mouth and open a customer support case with Adobe, requesting that they recalibrate the M8.

 

Text of my case is as follows: "I am (and have been for a number of months) trying unsuccessfully to obtain good colour with both LR1.3.1 and ACR4.3.1 with DNG files from a Leica M8. I have expended many hours running calibration routines to obtain settings for the 'camera calibration' module. Yes I know that colour is a subjective thing, but the colours which routinely come out of LR and ACR are not credible as opposed to incredible!

 

Since the Leica M8 was calibrated by your company, ACR 3.6 I believe, there have been a number of firmware updates for the camera and the majority of owners are using the IR cut filters to control the sensitivity the camera has in that part of the spectrum. Options exist in the camera menu to select whether these are fitted or not. They make a significant difference to the look of the image and therefore the settings needed by the RAW processor.

 

Would it be possible for your team to recalibrate the Leica M8 with and without these filters in place and update the algorithm settings which the user is unable to adjust in both LR and ACR.

 

If I use Capture One, then I am able to select a range of ICC profiles and easily obtain wonderful images.

 

I am not alone with my dissatisfaction with issues being widely reported by other Leica M8 users on web forums. Many thanks, Baxter"

 

I'll report back on progress, but inevitably it is one small voice trying to move a big organisation.

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So if we edit the name of the camera in the DNG we'll get the Leica color matrix being used by LR instead of their calibration which was done without IR filters ? Shouldn't that give better results ? The in camera jpg color tends to be rather good (often better that what LR gives without adjustment).

 

I am going to try it tonight to see what I can get.

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Having given the matter some thought, I decided to go to the horse's mouth and open a customer support case with Adobe, requesting that they recalibrate the M8.

 

 

Baxter/Sandy

 

Interested findings. I always felt something is wrong as Canon file does not have the same skin tone issues when I correct the WB shot along wth the M8.

 

Baxter, Please let us know what Adobe reponse it.

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Calibrating with i1 display or spyder 2pro hardware and using Color Eyes display pro software, I can get my i-Mac's display down further (even to 80 cd/m2) which I checked by measuring afterwards using x-rite software.

Brightness of screen and prints from Epson 3800 now are extremely close.

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I've looked further at LR's color handling. Here's what I found:

 

1. Lightroom's camera calibration in ACR 4.3.1 is identical to what's embedded in the later version of the Leica's M8 DNG calibration, the one that's been in place since 1.092 of the firmware. The color values match to the decimal point - best guess is that the ACR calibration is just taken from the Leica calibration

 

2. Calibration in the older (pre 1.092 firmware) DNGs is different, and there is a perceptible color shift if you override camera type to unknown. The attached files show a test chart with the new and old versions respectively. As can be seen even in the JPEGs, reds are less bright.

 

Numerically, looking at four of the GretagMacbeth patches, you get:

 

Blue Green Red Light Skin

New 35,30,75 55,76,45 75,37,27 87,79,72

Old 44,26,75 49,79,46 75,25,20 87,78,71

 

Its interersting to note that the light skin tone matches near exactly between old and new - presumably a design goal - but in other places red is toned down.

 

So, bottom line - so far as I can tell current LR calibration is exactly the same as the Leica calibration as embedded in current generation DNGs, but different to first generation firmware.

 

Sandy

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I love these skin tone discussions......as if everyone is caucasion with the same pigmentation.

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I love these skin tone discussions......as if everyone is caucasion with the same pigmentation. Get all the colors on the chart correct on a calibrated monitor and you will have accurate skin tones.

 

I couldn't disagree more. At present, no-one is caucasion with the current output from the camera.

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I couldn't disagree more. At present, no-one is caucasion with the current output from the camera.

 

 

The only point I am trying to make is that there is no "correct skin tone." I use an Expodisk to establish a color temperature when shooting the M8 and I have zero problems with color accuracy. I understand that your discussion involves the way the file is read by ACR after capture, but I haven't personally experienced any of these issues. For example, the shot below of my hand, taken just now, is straight from the camera with no adjustments in ACR. It may appear too yellow, but that is due only to the web compression. If you save it and open in PS, I think you would agree it has no abnormal cast. It was taken under fluorescent light.

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Adobe responded and said that it was a Technical support issue, for which I need a support plan and rejected it as a Customer Support case. I have just posted on the Lightroom user to user forum to see if there is any other way of getting the matter addressed.

 

Incidentally, I too use an expodisc Brent and whilst the skin tones look fine in your image, the wood looks like it has a greenish tinge.

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Here is the link to the thread which I started. lightroom user to user

 

So far I have been recommended to go to inside-lightroom calibration pages. The settings downloadable from there seem more extreme than those I have been using. Interesting feature on how to do the iterative procedure manually which Rags Gardner's script automates.

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Incidentally, I too use an expodisc Brent and whilst the skin tones look fine in your image, the wood looks like it has a greenish tinge.

 

As far as I know, it's not possible to have a color cast on only one part of an image. If the desk has greenish tinge, the hand would also have it.

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As far as I know, it's not possible to have a color cast on only one part of an image. If the desk has greenish tinge, the hand would also have it.

And so it has

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Colour calibrated monitors help... skin looks fine on mine.. and I don't see green in the desk...

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Colour calibrated monitors help... skin looks fine on mine.. and I don't see green in the desk...

To me the whole image has a green cast.

 

Has anyone had experience with adjusting the Hue and Saturation by eye on a calibrated monitor? maybe the only way of making a valid adjustment in ACR?

The key could be in finding the constant in the colors, by visible perception.

 

If I adjust for RGB value in tungsten or/and daylight the colors look bad in just about any scene, it looks like you can't really nail the Hue by measuring. But with eyes you might get some kind of perceptive consistency.

 

/Henrik

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