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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I will echo what Christian has said and add that ammonium chloride coating is relatively easy and inexpensive. It also works on a variety of 3D objects where
the surface morphology is in need of enhancement. We have coated not only invertebrate fossils, but vertebrate fossils (especially teeth), and neontological collections including egg shells, herpetology scales, fish scales, and, as mentioned, archaeological
lithic artifacts. A short video that includes ammonium chloride coating may be seen here:
<a href="http://www.youtube.com/watch?v=g-FiFtBQthY&list=UUtNiqiI7zdCFS8QGiiYYRfw">
http://www.youtube.com/watch?v=g-FiFtBQthY&list=UUtNiqiI7zdCFS8QGiiYYRfw</a>.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Roger<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Roger J. Burkhalter<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Collections Manager, Invertebrate Paleontology<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Sam Noble Oklahoma Museum of Natural History<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">University of Oklahoma<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Norman<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><a href="http://www.snomnh.ou.edu">www.snomnh.ou.edu</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><a href="http://commonfossilsofoklahoma.snomnh.ou.edu/">http://commonfossilsofoklahoma.snomnh.ou.edu/</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""> nhcoll-l-bounces@mailman.yale.edu [mailto:nhcoll-l-bounces@mailman.yale.edu]
<b>On Behalf Of </b>Christian Baars<br>
<b>Sent:</b> Wednesday, August 20, 2014 3:21 AM<br>
<b>To:</b> 'nhcoll-l@mailman.yale.edu'<br>
<b>Subject:</b> Re: [Nhcoll-l] Dusting/powdering skeletal elements prior to photographing<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">David,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">In palaeontology, invertebrate fossils are routinely dusted with ammonium chloride (</span><span lang="EN">NH<sub>4</sub>Cl</span><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">)
prior to photography to enhance contrast (often following blackening of the fossil), and in archaeology to eliminate reflection on shiny objects. The ammonium chloride is actually evaporated onto the specimen, which gives a very fine coating, much finer than
you could achieve with any powder. <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Ammonium chloride does not harm most types of objects and washes off easily with water, but will also evaporate from specimens/objects when left
in a fume cupboard (no need for solvents in case of sensitive objects, just takes longer). Please let me know if you need guidance on the technique of applying ammonium chloride to the specimens.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I have had some very good results photographing fossils using polarizers. Commercially available polarizers can be very expensive; have a look
on eBay for polarizing film which is very cheap, available in all sorts of sizes, and you can quickly and easily build your own purpose-made polarizer for any camera/microscope.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Kind regards<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Christian
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D">Christian Baars<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:8.0pt;font-family:"Tahoma","sans-serif";color:#1F497D">Senior Preventive Conservator<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:8.0pt;font-family:"Tahoma","sans-serif";color:#1F497D">National Museum Cardiff<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:8.0pt;font-family:"Tahoma","sans-serif";color:#1F497D">Cathays Park<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:8.0pt;font-family:"Tahoma","sans-serif";color:#1F497D">Cardiff CF10 4NP<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:8.0pt;font-family:"Tahoma","sans-serif";color:#1F497D">029 2057 3302<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:8.0pt;font-family:"Tahoma","sans-serif";color:#1F497D"><a href="mailto:christian.baars@museumwales.ac.uk"><span style="color:#0563C1">christian.baars@museumwales.ac.uk</span></a>
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">
<a href="mailto:nhcoll-l-bounces@mailman.yale.edu">nhcoll-l-bounces@mailman.yale.edu</a> [<a href="mailto:nhcoll-l-bounces@mailman.yale.edu">mailto:nhcoll-l-bounces@mailman.yale.edu</a>]
<b>On Behalf Of </b>David Katz<br>
<b>Sent:</b> 19 August 2014 22:34<br>
<b>To:</b> <a href="mailto:nhcoll-l@mailman.yale.edu">nhcoll-l@mailman.yale.edu</a><br>
<b>Subject:</b> Re: [Nhcoll-l] Dusting/powdering skeletal elements prior to photographing<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-GB"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-GB">Rachel,<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-GB"><br>
That is what I expected. I'm working on developing a developing a photogrammetry protocol for making digital models of skeletal elements. Photogrammetry does a good job capturing bone shape when the bones have texture or topography, or preferably both. However,
some bones, particularly cylindrically shaped bones that have been treated so that they are smooth and shiny, really offer photogrammetry software no noticeable topography from which to find overlapping points between a set of photographs. <o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-GB"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-GB">One option was to try coating the bones. It seemed to me this wouldn't be workable for the vast majority of collections. Francisco suggested a polarizer, and I will look into this. I hadn't heard
of it before, but I've now found some reports that polarizers and photogrammetry software work fine together. The final possibility that shiny long bones shouldn't be modeled using photogrammetry software.<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-GB"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-GB">... We'll see.<o:p></o:p></span></p>
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<span lang="EN-GB"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-GB">On Tue, Aug 19, 2014 at 12:50 PM, David Katz <<a href="mailto:dckatz@ucdavis.edu" target="_blank">dckatz@ucdavis.edu</a>> wrote:<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-GB">Hello,<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-GB"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-GB">I've been told that in order to photograph elements that tend to reflect light strongly (teeth, highly polished bones), people sometimes coat them with a reflection-reducing powder. I was even
told that baby-powder is often used.<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-GB"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-GB">Realistically, what do natural history curators permit? Specifically, are there types of powder coating that are particularly acceptable and non-destructive? Are standards different for recent
vs. ancient skeletal materials?<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-GB"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-GB">Thanks for you input.<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-GB" style="color:#888888"><br>
David<br clear="all">
<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-GB" style="color:#888888"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-GB" style="color:#888888">--
<br>
David Katz<br>
Doctoral Candidate<br>
Department of Anthropology--Evolutionary Wing<br>
University of California, Davis<br>
Young Hall 204<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-GB"><br>
<br clear="all">
<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-GB"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-GB">-- <br>
David Katz<br>
Doctoral Candidate<br>
Department of Anthropology--Evolutionary Wing<br>
University of California, Davis<br>
Young Hall 204<o:p></o:p></span></p>
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