A question for EBII's experts about Roman mosaics

[Boogie Knight]

This question has recently been raised at work about mosaics. I work on an archaeological heritage site open to the public, a Romano-British villa that had its heyday in the mid-4th century AD but was begun (the site had pre-Roman Iron Age occupation) in the early 2nd and was re-discovered and excavated by the Victorians.

I posted this in the VV forum but as soon as I had, I realised this might be a better place as it can be passed on to EBII's researchers. Any help I can get is hugely appreciated. I realise this isn't related to the mod at all so if it's out of place here, let me know and I'll nix it.

There are conflicting theories among staff and volunteers over whether a substance such as oil or beeswax might have been used to "brighten" or "buff up" floor mosaics, in particular those found in the triclinium (dining room). Truth be told, most of us doubt this as the very idea seems odd; some substances would become sticky and attract all sorts of dust and grime, particularly in a dining area, and other substances would surely make the floor far too slippery. We suspect the theory is a Victorian creation. But despite a lot of looking (we're lucky to have a fairly extensive library of our own, plus the books in the gift shop) and trawling online, we haven't found a single source mentioning the subject. I've read from a wordpress site that aims to show people how to make authentic-looking mosaics that they often buff up their tessarae with various substances, but none of these are intended for walking on and seem to be wall decorations.

It is, of course, difficult to prove a negative but we haven't really found much (very fleeting mentions) even of tessarae being polished before being placed in the mortar; which makes matters even more tricky as it's hard to explain why some of our colours are so vibrant. We've got limestone, granite and what IIRC is either terracotta or pottery shards, possibly both; none of the blues and greens that you sometimes get in Romano-British mosaics but what we have is very vibrant. Obviously we clean our own properly (de-ionised water and the like) but the Romans obviously wouldn't have had that.

I'm looking for any sources on the subject at all, because right now we've got virtually nothing.

[Kravixon01]

I don't know a thing about historical evidence for mosaic cleaning. But another good place to ask is /AskHistorians on reddit. I'm always amazed at what obscure details people are knowledgeable about, and it's a larger pool of people to ask than the EBII historians. You might find someone who studies Byzantine mosiacs, for instance, which might shed some light on the question.

That said, I use beeswax for archery. It's rubbed on bowstrings to stick the individual strands together and protect them from the weather. It's inconceivable to me that anyone could ever use it for cleaning, as it's gunky and somewhat sticky.