[Bonetools] Colouring bone

Wed Apr 16 21:21:25 CEST 2014

Green stains are normally caused by bronze objects or copper alloy scrap
associated with worked bones in the soil. Are the rivets all made from iron
or also from bronze?

Kordula

2014-04-16 17:15 GMT+02:00 Dave Constantine <dkconstantine at btinternet.com>:

>   Thank you all for your replies.
>
> Vincent, the green stained comb you linked is rather interesting. Do you
> know what the green pigment is? Also, looking at the images, it seems that
> it is no more than a surface colourant with little penetration, is this
> correct?
>
> Thank you for your suggestion of minium, I was at a loss about what it
> could be. It is not a fresh find, it was originally discovered in the 1960s
> (or possibly 1970s) and mounted on a card for display. To the best of my
> knowledge though, the colouring is original, though it is possible that the
> surface was also coloured and this has simply failed to survive.
>
> I have Arthur MacGregor’s book, and very useful it is too on the matter of
> colouring.
>
> Regards,
>
> David Constantine
>
>
>
>  *From:* Vincent Cattersel <vincent.cattersel at gmail.com>
> *Sent:* Wednesday, April 16, 2014 2:03 PM
> *To:* Mailing list for archaeologists of the research group for the study
> of object and waste of bone, antler. ivory and horn.<bonetools at listserv.niif.hu>
> *Subject:* Re: [Bonetools] Colouring bone
>
>  Dear all,
>
> this is a first where I might be able to contribute to this group, but I'm
> happy to do so:
>
> In 2008 I have conserved and restored 8 bone/antler combs from the
> Merovingian period at the Royal Institute for Cultural Heritage (Brussels,
> Belgium). These combs are currently preserved at the Royal Museums of Art
> and History in Brussels, Belgium.
> Here you can find pictures of a few of them (click on the pictures to get
> a zoomable high resolution image):
> http://balat.kikirpa.be/photo.php?path=X026849&objnr=20042741
> http://balat.kikirpa.be/photo.php?path=X035781&objnr=20052916 (green
> staining on the surface, carbon black in the circular motives)
> http://balat.kikirpa.be/photo.php?path=X026845&objnr=20052917
> http://balat.kikirpa.be/photo.php?path=X038388&objnr=20052919
> http://balat.kikirpa.be/photo.php?path=X035783&objnr=20052922
>
> Some of these where coloured and stained with green and carbon black. We
> used µ-XRF, µ-RAMAN and SEM(-EDX) to analyse the stains and the carbon
> black particles.
>
> So staining and colouring isn't that uncommon, as you probably already
> know.
>
> When I look at the picture, I can see that the red is slightly orange,
> which makes me think about the pigment lead red (also called 'minium' or
> lead tetra-oxide, Pb3O4). This isn't a surprise since it is one of the
> oldest known vivid red pigments (except for some iron oxide pigments
> derived from hematite and red earth or cinnabar (HgS), however they all are
> true 'reddish' in colour and lack the hint of orange).
>
>
> Some simple identification techniques for minium are:
>
>    - Ultraviolet fluorescence (if minium, it minium it should show a dark
>    red colouration);
>    - Infrared False Color which should gives the observed minium a
>    yellow-brown colour.
>
> Analytical techniques:
> In case you have the oppurtunity to analyse it with RAMAN, you can find a
> reference spectrum here<http://www.chem.ucl.ac.uk/resources/raman/pigfiles/redlead.html>
> .
> For a reference spectrum of minium using XRF: here<http://cameo.mfa.org/images/8/82/Slide16_FC199.PNG>
> .
>
>
> Another thing is the question whether this die was excavated and brought
> directly to your collection or was it once part of a (private)collection
> and excavated a long time ago.
> This is an important question since it could provide an answer to whether
> or not this colouration is original.
> I know from my experiences with the conservation of precious ivory objects
> that they are often repainted (repolychromed) throughout time, even though
> their iconography or typology gives us reasons to believe that they
> originally weren't polychromed or not polychromed in such manner as they
> are today.
>
> To get back on the minium pigment, more information can be found in:
>
>    - Eastaugh, N., Walsh, V., Chaplin, T., & Siddall, R. (2008). Pigment
>    Compendium - A Dictionary and Optical Microscopy of Historical Pigments.
>    Oxford: Butterworth-Heinemann.
>    - Feller, R. L., Gettens, R. J., & Chase, W. T. (1993). Vermilion and
>    Cinnabar. In R. Ashok, Artists' Pigments - A Handbook of Their History and
>    Characteristics. (Vol. II, pp. 159-182). Washington-London: National
>    Gallery of Art.
>
>
> Another book I can recommend on staining and colouring bone materials is:
> McGregor. A. (1985) Bone, Antler, Ivory & Horn: The Technology of Skeletal
> Materials Since the Roman Period.
> I don't have it here with me for the moment, but as you wish, I can always
> go through it to find more information on red staining or colouring.
>
> Yours,
>
> Vincent Cattersel
>
> Drs. VINCENT CATTERSEL
>
> *Doctoral researcher*Universiteit Antwerpen / University of Antwerp
> Faculteit Ontwerpwetenschappen / Faculty of Design Sciences
> Opleiding conservatie-restauratie / Conservation Studies
> Blindestraat 9
> B-2000 Antwerpen
> T +32 3 213 71 34 | F +32 3 213 71 35
> vincent.cattersel at uantwerpen.be
> www.uantwerpen.be<https://mail.uantwerpen.be/owa/redir.aspx?C=Gp6oB9zg6EOuD7R75-KaedCX7IvSydAI3RAu53oKfBVI3Qv2NuFbAdGDGuoXVIRgfT68F3LfWbc.&URL=http%3a%2f%2fwww.uantwerpen.be>
>
>
>
>
>
> On 15 April 2014 09:06, David Constantine <dkconstantine at btinternet.com>wrote:
>
>>  Hello All,
>>
>> Attached is an image of a (probably) Saxon bone/antler die. As can be
>> seen, there is reddish pigmentation in the decoration. I have looked around
>> for similar colouring and with the exception of a "lucet" from London I
>> cannot seem to find anything similar, just totally stained objects e.g. the
>> belt buckle from York. Does anyone here know of any Early Medieval dated
>> bone artefacts that are either entirely stained/dyed or have coloured
>> decoration such as this?
>>
>> Regards,
>>
>> David Constantine
>>
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>>
>
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