Giannis vs Polinik on the color of bronze :)

[Paullus Scipio]

Christian wrote:

Dear Paul,
1. well, you said the reddish bronze didn´t exist. That´s why I was arguing. However, items like Haltern #385 are not exceptions, they exist in large numbers (manly in pre-Caesarian context). I just took out one example from which I posted the complete met. analysis / alloy.
I didn't say that at all- so I think you may have misunderstood......I said this:-

whilst ancient bronzes varied, they were closer to modern 'yellowish' brass in appearance than modern 'reddish' bronze.....

note that I referred to variation, and later gave the varying percentages of ancient bronze.....and the most common are around 10%, and note I also said that the colour was 'closer' to brass than modern coppery/red bronzes, not identical and elsewhere said they could be hard to tell apart with the naked eye ( especially in differing light conditions!) I also said:-

it should be noted that 'modern' reddish bronzes such as phosphor bronze did not exist in ancient times

....in response to your reference to phosphor bronze - and you agreed that phosphor bronze did not exist back then !

2. Basically yes, that would be what we would expect, but again there are not enough examples of which we have an analysis to back up such a statement.

3. Oh, I think this is important. You were using the helmet as an example for the hypothesis that there were many "yellowish" helmets, plus that the coppery bronzes are rather a modern thing. In fact all these factors I named may have indeed changed the bronze from a reddish to a yellowish tone. IIRC these things are discussed in detail in the publications of the bronzes of the Mahdia shipwreck. As I said above, to find out what colour there was originally, we need to re-cast the alloy. It doesn´t help to look at the item as it is now.
True, I was using that helmet as an example of a 'yellow' looking bronze helmet - which it is, as even your photos demonstrate. There are many more examples I could have used, though few quite so good as hat one. If one wishes to see examples of re-cast alloys around 10% or so tin, then a look at Jeroen's site, posted by Greg, shows 'gold/yellow' bronze new-cast artifacts. Jeroen does point out, as Dan Howard did here ( and with which I agreed) that to a trained or discerning eye yellow 'bronze' can be distinguished from yellow 'brass' because one has a slightly 'warm' or 'rosy' hue and the other a 'cold' or greenish tint, but the distinction is subtle and a layman can easily mistake one for the other ( or even gold for that matter)......... and neither bears a resemblance to the coppery colour that we moderns associate with 'bronze' due to modern bronzes.....

[Paullus Scipio]

It gets more confusing. I just checked a book on metallurgy. It states that
1. brass under 20% zinc normally has a brownish-reddish colour.
2. bronze under 20% tin normally has a brownish-reddish colour.

only when the proportion of copper goes below 80% the red / copper turns into a yellow tone, on both metals.
I cannot verify this empirically, since I never made alloys with over 10% tin, zink or lead, but all the ones I made were rather reddish / coppery when cast and cleaned.

However, I see no reason to question metallurgical tables, I assume those statements are correct. To me it perfectly makes sense in regard of my experience in mixing Roman alloys.

A look at the two sites posted by Greg - Jeroen's and Neil's would seem to provide empirical evidence that 'ancient bronze' of around 10% tin is a decided gold/yellow colour ( which may have a rosy tint under certain lighting conditions). I also attach an actual example of a bronze sword found - which again is 'gold/yellow' coloured. The statements you have quoted would seem to be plainly wrong, since brass and bronze around 10% tin or zinc are 'gold/yellow' when new and polished - certainly not brownish-reddish! One need only look at Jeroen's and Neil's re-creations to see that. ( My father used to make brass artifacts when I was a boy, and used several types of brass, and coppery modern bronze, but I never saw anything a 'brownish-reddish' colour). Are those statements made in a different context perhaps??

What does this mean, then? As far as we can see from the Haltern finds, where we have a metallurgical analysis for (I think) all items, only a small amount was actually in a yellowish tone. The question is, in the end: Weren´t many / most of these items tinned anyway?
I don't believe you can extend a single find on a Roman site to cover Greek equipment of a different time period. Certainly only a small minority of helmets found show signs of 'tinning' - designed to give a 'silver' impression, and as Jeroen points out, one reason for using 'yellow' bronze is to give a 'gold' impression

And, following: Would a tinned surface on a helmet like the one from Sicily result in a yellowish colour nowadays? Hmmmm...
I'm afraid the tinned surface generally looks quite different due to the different oxidation, and because of wear patterns - see attached photos of a tinned Chalcidian helmet - note the bronze appears 'yellow/gold', with the remains of the tinning showing as dark patches - I've included one taken under a 'warm' light as well, so as to show how the bronze looks 'rosy' or warm under different lighting !! The photographer used a reddish light because everyone knows bronze is supposed to be reddish, :roll: but in the more natural lighting conditions of the other two photos, the truer 'yellow/gold' colour is visible.......

Besides:
In regard of low copper part in alloys, I think you forgot the mirror-bronzes in Antiquity, Paul. I just thought of them, and IIRC these often have below 70% copper.
Yes, quite right......if we are going to extend the scope of ancient bronze beyond Greek armour, perhaps one should note the many bronze objects from Chinese tombs, many untarnished, of 5-15% tin content - which again are predominately 'yellow/gold' coloured......

See
Friedrich Tabellenbuch – Metall- und Maschinentechnik, (Troisdorf 2008).
C. J. B. Karsten, System der Metallurgie: geschichtlich, statistisch, theoretisch und technisch (Berlin 1831).

[caiusbeerquitius]

1. well, you said the reddish bronze didn´t exist. That´s why I was arguing. However, items like Haltern #385 are not exceptions, they exist in large numbers (manly in pre-Caesarian context). I just took out one example from which I posted the complete met. analysis / alloy.
I didn't say that at all- so I think you may have misunderstood......I said this:-
whilst ancient bronzes varied, they were closer to modern 'yellowish' brass in appearance than modern 'reddish' bronze.....
note that I referred to variation, and later gave the varying percentages of ancient bronze.....and the most common are around 10%, and note I also said that the colour was 'closer' to brass than modern coppery/red bronzes, not identical and elsewhere said they could be hard to tell apart with the naked eye ( especially in differing light conditions!) I also said:-
it should be noted that 'modern' reddish bronzes such as phosphor bronze did not exist in ancient times
....in response to your reference to phosphor bronze - and you agreed that phosphor bronze did not exist back then !

Hi Paul!
I was, of course referring to this:

it should be noted that 'modern' reddish bronzes such as phosphor bronze did not exist in ancient times

The "such as", as you probably agree implies that you also mean all other reddish bronzes. Since this is not what you actually meant, we have had a nice misunderstanding.

True, I was using that helmet as an example of a 'yellow' looking bronze helmet - which it is, as even your photos demonstrate.

Well, I gave a lot of arguments why it may be not. Instead of repeating your argument, it might be better, i.e. more interesting for this discussion, for you to take position on those.

to a trained or discerning eye yellow 'bronze' can be distinguished from yellow 'brass' because one has a slightly 'warm' or 'rosy' hue and the other a 'cold' or greenish tint, but the distinction is subtle and a layman can easily mistake one for the other

I fully agree.

or even gold for that matter

I don´t agree. Gold is quite distinct.

A look at the two sites posted by Greg - Jeroen's and Neil's would seem to provide empirical evidence that 'ancient bronze' of around 10% tin is a decided gold/yellow colour ( which may have a rosy tint under certain lighting conditions). I also attach an actual example of a bronze sword found - which again is 'gold/yellow' coloured. The statements you have quoted would seem to be plainly wrong, since brass and bronze around 10% tin or zinc are 'gold/yellow' when new and polished - certainly not brownish-reddish! One need only look at Jeroen's and Neil's re-creations to see that. ( My father used to make brass artifacts when I was a boy, and used several types of brass, and coppery modern bronze, but I never saw anything a 'brownish-reddish' colour). Are those statements made in a different context perhaps??

Statements are bout how the metals reflect which wave lenghts of light at a full light spectrum.


How about this: I´ll make a 15% tin 85% copper bronze over christmas, and I´ll make a pic under natural light, after it is polished. Then we´ll see.

I don't believe you can extend a single find on a Roman site to cover Greek equipment of a different time period. Certainly only a small minority of helmets found show signs of 'tinning' - designed to give a 'silver' impression

What single find? There are quite a lot of finds there. But of course one cannot make this exemplary for the whole of antiquity... but then we don´t have that many sites, where we have hundreds of met. analyses, like Haltern.

As any restaurator will be able to tell you, tinning normally wears off in the ground. Most items that once were tinned show no or just few traces of tinning when found. I was just trying to include this as a possibility, which also has to be taken into account for our considerations.

The photographer used a reddish light because everyone knows bronze is supposed to be reddish, but in the more natural lighting conditions of the other two photos, the truer 'yellow/gold' colour is visible.......

Note that most lighting used (flash) has a certain light spectrum, which becomes even more visible when you make a picture. So any photographies made not under natural light are quite useless for a discussion of highly polished objects with an often mirror-like quality, methinks.
For a good explanation look here:
[url:2zycyvob]http://www.photoxels.com/tutorial_white-balance.html[/url]

[Dan Howard]

There is no point using photos on this forum to try and prove your point. Especially since quite subtle hues and tints are involved.
1.It is very difficult to get the same colour in a photo as the real item
2. the colour distorts as soon as you save it in a compressed format such as jpeg
3. the colour distorts even more when viewed on a computer screen. Every single person viewing the image will see a different colour depending on the video card, the monitor, and the settings of both.

The best you can do is to find various examples and use the same camera and lighting to photograph all of them and then post them all together in a single image. The colours still won't be right but at least a comparison can be made and differences noted.

[hoplite14gr]

To make matter worse:

A friend of mine (mining engineer) said that the composition of the ore extracted also affects metal color.

Copper ore from Larymna is very different from the Cypriot ore not to mention imported staff
Same applies to tin and zinc.

Ancient Greeks spoke of "oreichalkos". I am not awarw if any description for its composition comes from ancient source.
So I cannot be certain if only brass or only bronze is being defined by this word.

Kind regards

[Giannis K. Hoplite]

And since this thread has my name in there,here i join too.
I will post many photos side by side,just to demonstrate how bronze colour can look different according to the lighting,or the camera settings.

These are all photos of the same helmet,and you see how it can look "golden" or redder,and you can compare with that other MI armour which is the same alloy,and under white lighting it looks pink!

That said,completely polished ancient greaves that i have seen in Thessaloniki museum were very yellow.
http://i118.photobucket.com/albums/o118 ... eapons.jpg
http://i118.photobucket.com/albums/o118 ... C02268.jpg
http://i118.photobucket.com/albums/o118 ... C02271.jpg

Note that these have no patina,like the Munich helmet and greaves,they are highly polished and reflective! They have a different shade that common brass. Especially highly polished modern brass has a white-green hue which no bronze has. But they didn't have any red hue either. Now,problem is these are the only ancient bronze items that have maintained that high gloss. Certainly,many helmets have a fine yellow patina,but still,it's a patina. In fact,oxidisation from my fingerprints on my phosphor bronze helmet leaves a yellower mark! But other helmets have a fine red patina. So neither can be used to determine the exact shade of the polished item. But i've found that those greaves i posted,those two pairs from Macedonia,are exceptional. I checked if they were guilded or something,but no,it was the actual polished bronze!
Khairete
Giannis

[Paullus Scipio]

It is a curious thing, but a quick survey reveals that whilst there could be a variety of shades of bronze, depending on the exact mixture in the alloy, most ancient bronzes are around 10% or so tin, and are distinctly 'yellowish' rather than coppery red. The British Museum, for example, refers in its various literature to "the bright golden colour of bronze", and a Chinese museum, when creating a 'virtual new' representation of a cauldron from 800 BC refers to "returning the bronze to its original shiny gold colour", and between these two are many more references to 'golden' or 'yellow' being the normal most common colour for ancient bronze....

Ancient literature and iconography too refers to 'yellow' and 'golden' bronze, and in painting bronze is almost invariably depicted in yellow, not orange or red.....

In looking at various modern shades we find that 20% tin gives a very golden colour, 10% a distinctly golden yellow colour, but at 8% tin the bronze starts to take on a distinctly 'pinkish' tone quite suddenly.....

[unfounded ad hominem remarks culled by moderator]

I don´t agree. Gold is quite distinct.

I think that depends on the experience of the beholder - after all, we have the fact of Helots believing gold was bronze, and in Giannis' post he refers to asking if the shiny 'yellow' bronze greaves were gilded, and I have even seen museum descriptions describing 'yellow' bronze armour as "gilded" when it is not.....

[unfounded ad hominem remarks culled by moderator]

What single find? There are quite a lot of finds there. But of course one cannot make this exemplary for the whole of antiquity... but then we don´t have that many sites, where we have hundreds of met. analyses, like Haltern.

Apologies for any confusion - I meant that Haltern is a single site from a fairly narrow period ( even if many artifacts are found there), and as you yourself point out, it can hardly be regarded as exemplary for the whole of antiquity, and certainly not for the Greek/Hellenistic period.

Note that most lighting used (flash) has a certain light spectrum, which becomes even more visible when you make a picture. So any photographies made not under natural light are quite useless for a discussion of highly polished objects with an often mirror-like quality, methinks.

I think we are all in agreement on this - see my earlier post, and also Dan and Giannis' posts....

[Giannis K. Hoplite]

One more demonstration.
This is my DSC phorsphor bronze illyrian helmet when it was finished,but hadn't received the final polishing. It shows what i said in the previous post. That oxidisation from fingerprints makes a yellowish colour. If i could find a chemical to apply on my helmet and achieve an homogenous such patina,i would certainly try it on my helmet. For some reason my bronze is much more sensitive to fingerprints than my brass one! :evil:

Khairete
Giannis

[caiusbeerquitius]

Let´s call this the "much-more-civilized-than-the-tunic-colour-debate-metal-colour-debate" (mmctttcdmcd)

Hah. There was me, hoping... I´m out of this discussion.

[KrimzonKnight]

any chance that ancient bronze had silicon? I came across an armorer who claimed that ancient greek armor was made from silicon bronze. Iv seen photos and it does have a golden color to it. I was just wondering because this is the only place where iv ever heard that and wanted to check its validity.

[Dan Howard]

IIRC silicon wasn't deliberately added to copper alloys until the 20th century but it might be present as an impurity in some ores.

[KrimzonKnight]

So what your saying is thats it theoretically possible for ancient greek armor to be made of silicon bronze? would it be any more accurate than phosphor bronze? I believe it was states earlier in the forum that ancient bronze didnt contain phosphor, but it seems the best available helmets are made from that.

[Giannis K. Hoplite]

The best availlable helmets are made of phosphor bronze, because their makers cannot find better material in big enough pieces easily. It is also a matter of taste, but many people (me included) prefer it to commercial brass, which neither has the correct metal allow nor a closer percentage of copper to the originals than phosphor bronze.
There are better alloys out there, but too difficult to find and especially in sheets of a reasonable size to make helmets and armour.
Khaire
Giannis

[Dan Howard]

So what your saying is thats it theoretically possible for ancient greek armor to be made of silicon bronze?

No. Greek armour was tin bronze. Some examples had a small percentage of silicon and other elements as contaminants. It would in no way be accurate to make a replica of Greek armour from modern silicon bronze.

[KrimzonKnight]

ohh alright I see. Thank you Giannis. would you say that phosphor bronze is close to the ancient bronze greeks used in terms of toughness?