I was playing with this last weekend. This is what I got:
I used a three layer shader, an just tweaked the diffuse texture in GIMP to get textures for the different subdermal/epidermal layers.
Interesting tests ben
Please, next time, covert them to a sRGB profile before posting. How do I know that these pink like lights are what you see in your monitor? I’m sure that you see something better there. This is a common mistake among posting users. Use always sRGB.
since we are still on colour management I thought I’d add these.
The first image is Baos version 5 with one instance of sss, colour corrected for skin tones. Notice that the head on the left has a plastic doll pink look while the head on the right has an english skin look ( bear in mind that the guy in the picture is english ). The skin tones are much closer to the original texture.
I find that whenever I apply a photographic skin texture to a model, blender always delivers it in dolly pink flavour. I don’t understand why!, the colours are there and almost always, can be pulled by tweaking the green and blue channels.
Perhaps it has something to do with how blender interpolates the original texture.
The second image is Baos version 5 rendered straight out of the box again it has that dolly pink look. Again the original skin tones can be pulled by tweaking the green and blue channels but not to the same extent because this file has three instances of sss.
Ofcourse the monitor, coloured lights, etc., will play a part in the final look, but look at the first image again and see just how much variation there is in the skin tones. All this colour is already there, notice that the yellows and tans are brought out while the pinks and red remain red, yet in the comparative image everything gets a pink wash.
Attachments
In post 113 you have my last render and you can download the last scene (version 7 if I remember well). Compare the color of the face in that post 113 to the lower left image in this collage below (and yes I was tempted to do this hell of hair but I realized it would look like a bad girl hair so I decided do a more normal one).
http://img690.imageshack.us/img690/4597/starwarsy.jpg
ben : I also find a little too pink your render don’t you think?
If what you’re trying to do is give your character a tan, then you’d probably be better to modify the skin texture or make a new one using photographs of someone who’s skin colouring matches those in the reference photo.
if possible can you make a render with all the light colors set to white, subsurface scattering disabled on any shader that use it.and the background set to a natural grey
@Tyrant Monkey
The centre image is rendered a you suggested. white light, no sss, 50% grey background.
I think you’ll agree ( all things being equal ). It has a definite pink quality to it.
Images on the left and right have a 20% sift in the blue and green channels and contrast shift for highlights and shadows.
The image on the left is in my opinion still pinkish the image on the right is bais towards the blue channel but the skin tones i.e. the pinks and tans are more congruent.
Attachments
Honestly I don’t think there is any red been added to the render at all, I downloaded the file that Bao provided and the colour map has a lot of pink in it already, I think his skin must be pretty pink to begin with. The color map look about the same as the middle render which is the render without subsurface scattering. A better way to test this is disable subsurface scatter and comp nodes and tweak you color map in GIMP desaturate it. I suspect if you did this and than sampled you render you will find that there is no bias as it will still be gray with no hint of pink to it. I have the file so let me go and carry out that experiment.
Okay I did my test I took the original color map and desaturated it in GIMP so it was essentially just a grey scale image. I disabled compositing, I also disabled SSS on all nodes and made sure the specular color was white on all nodes, the color map was been multiplied is also now multiplied by a gray value of RGB (0.93,0.93,0.93) the original shader had a slightly different blue channel. With all this done what I basically got was what I expected to get blender internal does not add any bias towards red. The skin that is rendered has true gray values
if you take a sample on any part of his skin you will find that the RGB are gray. But this skin shader that is been used to me is less than ideal its doing things that I feel are a little but unnecessary and I can’t seem to figure the principle that is been used to construct it, the logical of it is living me a little baffled.
Yes, I don’t see blender internal tints also (and I am also thinking it was excesive pink I used in last file).
What do you want I explain about the spaghetti node shader I used?
The shader has two SSS nodes (simulating epidermis and dermis) that are then overlayed with the color texture to give them color (other shaders don’t do that and I think in blender internal is a good thing and Jose Conseco was the one using it and I copied). Then it is added the backscattering (strangerman great backscatter) and several layers of speculars (as explained in a blenderart magazine about seven layers SSS shader).
The mixing of the SSS is done using a mask so you can have control of where you want each SSS (the ears and mouth have the greatest SSS for example).
Well, I was doubting if upload a luxrender image but I remembered yafray images were posted so this thread is not blender internal only I think. So here is my first luxrender image. I loaded the original render in gimp and duplicate the layer, blurred 5x5 pixel the upper layer and put its layer mode to overlay, that is called “the flow effect” if I remember well, it gives more depth to the shadows and makes more uniform colors. I usually don’t postprocess renders but with luxrender it is a must or you need very high render times to get rid of noise. This was a 20 minutes render.
Well, that was not really my first render in luxrender. This was the first one:
You can’t believe how difficult is to give SSS in luxrender. It lacks a very important feature to make it easy: abillity to mix two scatter materials (or two materials with two different “Interior” volumes). So instead I had to use Interior volume for the ears but the rest of the face is using “translucency” of a glossy translucent material. That is not a good solution but just a workaround, I will try cry sufficiently high to luxrender developpers implement a mixing of two Interior volumes now. 
An impressive render.
Should we find a different subject for testing now? LOL
Yeah, we need some scanned girl now definitely!!!. I also was thinking some days ago that I was never so much time near a head guy in my life!!! 
If someone from Weta Digital can post here some scanned 3D model of some well known actress with texture maps and such be welcome!!!
Jeanphi answered me and the ability to mix two volumes will be in next luxrender 0.9 but not in 0.8 final (they are just now in 0.8RC3). So some months yet to achieve a more realistic face in luxrender. The above is using only SSS in the ears, but in the face is using translucency (because you can’t have two SSS effects in luxrender in the same material at the moment). So the face has that yellow tone that is tricking a little our eyes believing it is SSS effect.
Posting a model of a black skinned, or dark skinned character would be good as it’s surprisingly hard to shade & light that kind of skin realistic.
Thanks on the explanation on your shader. If I remember correctly all the three layer skin shaders types that you see floating about in Blender where based off Maq’s shader were he tried to emulate mental ray’s fast SSS skin shader.
Just some questions about your shader is there any particular reason you use the bump map across so many nodes?
I was using a little displacement in the mesh (modifier) and a little bump to give detail. It could be done using only the modifier displacement but it would need a very high setting making the render much much slower. Just a little displacement and then bump I thought was giving similar result with less render time.
Bump in the four reflection layers is a must or you have a flat surface if there is no bumps in the reflections.
So your question would be about the bump in the two first layers. I think I deleted the bump here and then put it there again but I am not sure now if it can be deleted with a similar result. I think I did the test and decided it looked better using the bump also in the two first SSS layers.
I get it. But does it make it that much of a difference to use it because three 6K maps chew up a lot of memory I must play around and see if it is possible to just get rid of the bump maps.
but that Lux render head is pretty close for me its closer to the truth than the Blender ones so far I think if it had some SSS just to soften the bump map up and to add some color bleeding in the shadow terminates you would be there.
Vray has a killer skin shader so if someone has that it would be interesting to see some results from it.
Resample the maps to half or lower, is not needed 6k maps if you are going to render much lower image resolution. The correct way is two times what you get in the render. I mean: Render and look how many pixels the face has in height. Imagine it is 530. Well, then you need that the face in the map has at least 1060 in height (not the height of the entire map but the face in the map).
There are two ways:
First and correct: Using photographs from a black man to create the texture
Second and wrong but quick: Modify an actual texture of a white man.
I tried second just for practising. In gimp I created a void layer above set in multiply. With a black man photo as reference I was taking samples of his face and painting with a big brush in the void layer, I used around five different colors. Then set this multiply layer to 67% and collapsed. I found that the reference image had no pink areas at all but my image was having several areas very pinkish yet. So I color balanced giving a little green and mainly yellow. Then desaturated a little the image and luminosity a little less too. Used that image in the luxrender image and the image below is the result. Obviously the glossiness is not right, seems like wet so around half of the actual reflection would be sufficient for a black skin it seems. It seems also very reddish (seems more chocolat than a guy almost LOL). I usually sample the color I have in the render and compare with the color I want (sampled in a reference image). Substract both RGB values and I have an RGB value that I create a layer with in Gimp and then use mode Substract and render again using the corrected image and compare again how much near is then the new render. In this case I am not going to do this but obviously the image is reddish than a black man is, but I think it is because the material I am using; not the texture in this case.
Around 15 minutes cooking time:
I recooked the image in post 149 and this time just what the renderer outputs, without any modification in gimp:
It is 1 hour cooking time (but with 40 minutes I think is the same image quality too).
Download blender 2.57 - luxrender 0.8 RC3 file here: http://www.gamefront.com/files/20238543/Infinite_Head_Luxrender_7z (right click don’t works, you must click the link and then click the download button)
