Some more tests.

Wow those are amazing. The very faint scratch pattern in the clock bells are perfect!

All these renders are great.

If you could, please share how your material was made on the clock bells to make the smudges look so real. It looks so good.

For the clock I would recommend using thin film for the glass on the front of the clock and making the model of the glass have no thickness. This should make it clear faster with virtually no change in how it looks.

Here is the map I used (although it's half size here, otherwise it was kind of big). I created this from some photos I took and mashed together to create a nice crusty grunge map. It kind of looks like the Shroud of Turin but it's just some pictures I took while walking by buildings, etc.

The gold material uses two bsdf layers, one very sharp the other fairly rough (I think 40%). The sharp layer uses and IOR value coupled with an extinction value (n.225 k2.95) or something close to that. Those are actual measured values I found on the interwebs.

The rough layer I just used a high Nd value (40). The mix between the two is 100/10 with this grunge map used in the rough/10 layer.

And for the sake of laziness I just applied it using cubic mapping.

That's it.

I agree with the smudge/sacratch map it looks fantastic, models and their detail are great too, very nice work mate.

I used a more organic HDRI for this one and also replaced the glass cover material with a basic thin film as suggested.

I messed around with translucency last night. What is the difference between the Basic material's translucency function and the SSS function?

Doing3D have you seen the tutorials here.
http://www.thearender.com/cms/index.php ... rials.html
Number 8 kind of explains the difference pretty well.

This one helped me get a better sense of material layering.