I just updated to Poser 13.1.449, it has somehow applied a Gamma Correction to all my Cached Renders? Has anyone else encountered this?

Before

After

it must be set as a default for your Post FX. check to see if you have "Apply Post FX to Render" checked in your render settings

Thanks for the reply! No, that is not checked. Plus, that is for the Superfly Renderer and none of those cached renders are Superfly. Any new renders preview and export fine. It's just the previous renders that were in the 'Recent Renders' window from the previous version of Poser are affected.

Im having the same issue.

Also, some skin shaders are rendering very differently, with the same exact settings.

Or perhaps it's some crazy color correction Post FX that's being applied without me setting it.

Will open a ticket tomorrow.

Using the last Poser13 (13.1.469, I've noticed that the triple values I used to have in the PrincipledBsdf's SubSurface Radius input had to be divided by 10. Failing to do this, I' retrieve my skins with a similar ghost effect.
Wasn't the case with 13.1.449 and before.

My new skin shader seems to still be working. what are you guys doing with skin?

In my case, I'm using the same setup:

I just had to divide by 10 the three values for the SS-radius

And here is what Bondware tells on the Poser online doc:

I have my skin set to .11   .03    .015

In fact, even using my values, with this character, there's still a weak ghost effect:

Using yours:

But if I divide your values by 10, that's perfect:

So that there must be some something else that impacts that much the result

Speaking of the slight ghost effet: culprit found.
Now my values: 0.0482, 0.0169, 0.0109 are good, but a mystery remains: why divide by 10, be it my or your values, Ghostship.

I'm not sure what the heck is going on with your shader. Mine is a little less complicated and is working even if I plug the redfilter into the subsurf

Does the effect in the render change if a different skin texture is used?  Technically, we are assuming everything is working the same where the Material Room is concerned but are we expecting the same results when different character textures are exchanged?  I wouldn't think so if your redfilter node output yields a different red channel grayscale.

You are plugging the red channel of the diffuse into the strength of the SSS, which make the SSS multiplier entirely dependent on brightness red channel in the diffuse texture. Every face texture will have a different multiplier when doing that. Your SSS scale is to high, needing 10 times reduction. 

Basically, your blowing the SSS up. Cycles averages around 0.003 to 0.03 for scale (subsurface in the principled node).

If 0 is black, and 1 is white, 0.003 to 0.03 is a very dark color.

Your basically using 0.3-0.4, which is about 10 times to much on the max side......

That is my observation.  There is a very delicate balance between the SSS Scale and Subscatter radius values that needs careful optimization to achieve the ultimate render.

You are plugging the red channel of the diffuse into the strength of the SSS, which make the SSS multiplier entirely dependent on brightness red channel in the diffuse texture. Every face texture will have a different multiplier when doing that. Your SSS scale is to high, needing 10 times reduction. 

Basically, your blowing the SSS up. Cycles averages around 0.003 to 0.03 for scale (subsurface in the principled node).

If 0 is black, and 1 is white, 0.003 to 0.03 is a very dark color.

Your basically using 0.3-0.4, which is about 10 times to much on the max side......

You need to get the values going into the subsurface node under 0.1. Preferably lower. Then experiment with the distance of each color and tweak from there. I prefer to use an SSS map and all my upcoming characters for LF2 use SSS maps to modulate the SSS accordingly. You need different amounts of SSS in different areas, and you cant do that without a specific map to do so.

I would also uncheck use legacy scatter.... Unless your trying to match older versions of Superfly, there is basically no reason to use the old Cycles SSS algorithm in Cycles X.

In fact, after having read twice or thrice your last response, just to be sure that I got all details (lol) I've restarted from Ghosthip's thread on the skin, changed and corrected many details. Now, I will have to check with even lighter skin to be sure but to me that seems good enough:

Now, the SeparateRGB is again connected to the Subsurface Scale and to the Clearcoat inputs, without getting ghost effect, and the Radius values are (0.004820, 0.001690, 0.001090) which is what is on Poser's PrincipledBSDF node page.
I've unchecked the Legacy Scatter and I remark a slight difference on the nose: slightly more luminous, but that's subtil, so that I'm going to have more tests for this. Note that I haven't seen any difference in terms of speed. Unfortunately, Poser's Manual is silent on this point, the only thing we know is that it avoids SSS glow, but not if it's checked or not checked, so that I will see in the long run

Anyway, thank you so much for your help 

Just to give you a few more ideas. The is one my characters, SS Lorraine, for LF2. The scene is lit entirely with the Small Studio_05 from HDRIHaven rotated 180 degrees to put the light in the back in a custom background shader I whipped up for promos. I am using the Poser Physical surface node. The only thing done to the image is to overlay the partial SSS map and the arrow. The character render is a strait out of Poser using Optix, and Posers PostFX.

The scatter (scale) is set to 0.03. The depth of red, green, and blue, are all set to 5mm. No that is not a typo, 5mm

The difference? There is a depth map to control that 5mm depth, and lower it in a much more controlled manner than just using the red channel out of another image that has nothing to due with SSS at all.

This is one of the best ways I have found of doing SSS in just about every 3D program that supports it.  And it works just as well in Poser. This is basically the only way to control it properly; using a map that defines what is actually supposed to be going on under the skin, all over the character. You get full control over all 3 channels depths, up to the max depth you define (white would be 5mm in this case, full bore on all three channels). Other content uses the same approach, for a very good reason.

Keep in mind that I have Scatter Scale set to 0.03, (which is the same setting as Subsurface in the PrincipledBSDF node). And the depth at 5mm.......

You need a lot of nodes to do this with the Cycles root, and it is not very easy to do with the Principled one without node spaghetti either.

This skin shader has 5 nodes.  3 textures, a separate rbg, and the Physical root set to walk fixed. That's it...

The only better way I have found to do this, is with 2 layers of SSS, which requires one more map and a few more nodes.

Keep it simple, it actually works....

I understand, thank you for the explanations. Out of reach for me when it comes to draw a depth map. I'm unable to create decent make-up so that a depth map, wow 

It would be interesting to learn how you approached the creation of the SSS depth mapping layer.  I always contended that the Scatter Scale on human figures should be kept low, anywhere between 0.010 to 0.03.  Going above 0.05 causes over-SSS glowing problems.