i've been using snarlygribbly's wonderful ezskin 2, not enough to be more than a newbie with it...  but in my last scene, i used the special effect  "very wet skin high bump."  it looked great with my preview renders to the scene window, but when i changed the render to 1600x2600, some of the water drops picked up a red tint.  (the tint is more blackish if i dont use sss to render.)

   i'm using the 'office stairway' HDR light set, to give a blue tone to the scene.  i have blue-tiled walls, and white, grey, and slightly bluish light.  i thought maybe there was something whacky with the reflections, so i added the EnvSphre to the scene, but that didn't change anything.

   does anybody know why the water drops are changing colour?  and how to fix it?

do the colored drops change position if you use a different camera angle ?  some drops look fine while others are colored.

What happens if you render without displacement?

There are bugs with SSS and displacement at higher render resolutions that don't appear readily at smaller resolutions. This doesn't look like the same thing. But I'm curious anyway.

Turn off all your lights.  Render with each of your scene lights on individually to isolate when the spots are appearing. 

@marks

   yes, only the upward facing drops seem to be affected.   that's why i think it's some sort of reflection or... refraction, maybe?  i want to check these other tests before i muck with the camera. 

@moriador

   if i render without SSS, the drops are still discoloured, but more black instead of red.

@h:

   okay, rendered with just my main light (it's a point light), still red.

   well, the specular-only light only gave me a greyscale rendering.  it looks okay for what it is...?

  HDIBLVFXwhatever light only.  still red.

uh... what does that mean?  :/

okay, more tests...

moving the camera...

   well, the drops on the top of the arm there seem more white/clear, but i do see red edges towards the top/back.  and those vertical ones behind the hand, those still look like knife cuts.  :X

rendering with no displacement...

   well...  ah, there is no displacement.  it's a bump of 0.000127.

let me try turning off the reflection...

  no... still red.

i'm stumped.

okay!

   i did the stupid backwards thing and switched the bump to displacement, and now it's fine.  well, on the arm.  we'll see how the full render actually goes...

go figure.

okay, hold the phone....

  i plugged the bump into the displacement node, but i didn't turn on displacement rendering on the side. 

i'm rendering the displacement now, and its making the edges of the figures jaggy.  sooooo.... um, i'd really rather use the bump setting instead of displacement, but not have it turn red.

any other ideas??

Lower the displacement value.  Displacement maps will alter the mesh whereas bump maps will not.  BTW, which Poser version are you using and what are your Poser measure units?  Pro or regular, inches, centimeters, or other?

thanks, h...

   um, but i want to use the bump, instead of the displacement.  i did lower the displacement value.  i lowered it until the water drops facing forward had a decent dimensionality (and weren't, like, 2" spikes).  oh, you mean turn it down even lower?

ah, i have poser pro 2012, with the latest sr i think.  3?  3 something?  and measurement units?  hellifiknow, let me look...

  um... since i can't find it in preferences... default?  poser units, as far as i know; i've never had any reason to change it.

oh wait i found it!  meters.  sorry.

Are you using gamma = 2.2 in your render settings?  And if so, are the gamma settings in your bump/displacement maps set to 1?

gamma = 2.2; it is not turned on, however.  i've never touched that setting.

gamma settings in bump/displacement?  uhmm.... no?  there's no gamma settings.  that i can find.  i'm using the ezskin2 'bump blend.'  it's blending... a blender of some math functions (noise), with another math function (looks like 'add 80% to 0%' and comes out white), blended with a fractal blend.

oh, did you think the bump/displacement map was an image?  i don't see any gamma settings anywhere on those, either.  sorry.

On displacement/bump/transparency nodes, click on the field which loads the associated image.  This action opens the texture manager.  It is there that the gamma settings for the images reside.  Now, if you are not actively using gamma in your render settings then this becomes a mute point.

ah, okay, i see it.

it appears to default to 'use render setting gamma.' 

and right, i'm not using gamma, and these bump nodes aren't using image maps, so.

   we're stumped?

   i'll poke snarly for some insight.

Try changing the SSS node from Skin 2, too Skin 1 or milk.

heyas; thanks for checking in, david.

   well... the SSS node was Skin 1. 
Skin 2 had the same result.
WholeMilk had some darker colour.
SkimMilk had some paler, rusty colour.

   still all discoloured. 

   i also tried taking out the colour for the HSV on the skin, and the base colour chip.  still blood drops.

Would it be possible to see a screencap of the material room?

As hborre says, a screen shot of the shader in use would be very helpful...

but here's the shaders.  i didn't unroll them all-- let me know if there's anything pertinent i missed.  below are the bump shader bits.

okay, there's a buncha math functions that are making that dotty bit.  blended with that math function that seems to be 80% white.  blended with the fractal thing that makes the water drop shapes.

okay, i was looking at the reflection shader, and wondering if the red came from some reflection colour.

it isn't. 

i changed the 'background' reflection colour to hot pink, and the render came out exactly the same as using black, there.

so i don't know what it is.

Clearly, the displacement is picking up the skin color.  Note the image on the PoserSurface, the displacement around the legs are picking up red from the skin texture.  There is something going on with the shader nodes.