Hi guys,
I am trying to create an image of a bottle of wine (cabernet) in the style of the high end ads you typically see for these sorts of things. I’m having a number of problems but the main one is this: it’s green.
Now bottles of red wine are usually green, but if you look at a full bottle of red wine it really looks a very deep blue/purple, almost black, with creamy coloured reflections:
And to prove this to myself I just bought one from the bottleshop. (I can always use it to console myself later if I can’t figure it out.) It’s hard to tell that it is green until you hold the edge up to the light. Unfortunately my CG bottle is green and looks green:
Now I’m pretty sure I’ve got the IORs correct. I followed the advice from here:
I have volume absorption on the wine and I have the actual colour swatch from the specs for a glass bottle of this type. Nor does the problem seem to have anything to do with how many samples I throw at it. The lighting needs a lot of work but regardless of how I change it it still comes out green.
What I think is happening here is you’re using the glass shader by itself, which colors the reflections in an inaccurate way, so your reflections come out green. Try using a layer-weight or fresnel node to drive a mix shader mixing a refraction shader and a glossy shader and see if you get more pleasing results.
Which is a big improvement. You can even make out the green of the bottle at the top where there is no liquid. Now if I can just throw more light into the scene I think I’ll be getting close.
I’m struggling to get the nice bright highlights down the edge of the bottles. If I turn up the lights I just blow everything out. In the photography videos I’ve watch they achieve this with bright softboxes or strobes emitting through vellum, but trying to mimic that approach in blender doesn’t produce the same effect. The glass just dosen’t seem reflective enough.
Your clamp settings on the render panel are completely wrong and they are clipping your direct lit highlights. You should never set them as low as 1 (I have seen a few people do this recently - I’d love to know where they are getting the idea from).
I usually set my direct and indirect clamp values to 10 and 3 respectively (direct should always be higher). You’ll need to adjust your lighting afterwards.
