Good morning
In Octane renderer it was quite easy to generate a stencil like effect where you just applied opacity to the standard shader so the texture underneath shines through like with a gray PP stencil foil:
Which comes close to a photo:
With cycles renderer there isn’t any opacity settings for the standard shader…tried to mix two principled BSDF shaders, but doesn’t look as good:
Any hints would be great (o;
thanks
Can’t you just texture map and remap that value, then send it into alpha?
So black and white texture -> possibly invert -> multiply 0.8 -> principled alpha.
Possibly also use it as a bump map.
Although for paper I usually use a more complex setup to get refraction and translucent effects; which here I would in the end simply mix with a transparency shader.
What would be the octane shader setup? You’re already using alpha (opacity), I don’t see what else effect is needed.
Principled doesn’t do translucency. My setup would involve mixing diffuse, translucency, refraction, transparency for the absorbent part, then fresnel mix that with glossy, the mix transparency at the end for opacity masking. If using IOR based fresnel, the IOR needs to be inverted (1/IOR) for the backface.
With Octane it is just simple as:
Though I prefer to use 2.80 as it has a better UI for a beginner like me (o;
And Otoy hasn’t published their 2.80beta to the public yet…
besides…almost no add-in is working with Octane (o;
If all it does is “opacity”, then it should be only principled’s alpha.
Hmm…you are right…what confused me is the in the 3d viewport preview the material is much darker as in the final rendering…
E-Cycles preview (64 samples):
E-Cycles rendering (128 samples):
Hmm…with regular blender 2.80 and cycles the preview is fine:
Okay…seems I have to report it to Mathieu (o;
How does the background appear through the real thing if you add some distance between them? Does a shadow appear from the backside? What’s its reflective properties? This is generalizing of course, and although I agree that everything doesn’t have to be generalized all the time, that is what I do, so… 
Although you may have you what you want for this particular case, I wish people could do some more observations on the real material - we’re supposed to use the tools we have to mimic what we see - but seeing seems to be a lost art. Also, in this case, why did it not occur to you to mention it was E-Cycles? I’m on AMD everything, so E-Cycles issues are not what I would get involved with.
