[Nhcoll-l] Dusting/powdering skeletal elements prior to photographing

Wed Aug 20 15:55:14 EDT 2014

Thanks!  I am thinking of giving the following sources a try...if they
don't work out I'll go the glass blower route.

http://www.crscientific.com/dryingtubes.html

http://www.avogadro-lab-supply.com/item.php?item_id=838

Cheers,

VRR

Vanessa R. Rhue
Assistant Collections Manager
Department of Vertebrate Paleontology

Natural History Museum of Los Angeles County
900 Exposition Blvd
Los Angeles, CA 90007
Tel. (213) 763-3248
Fax (213) 746-7431
www.nhm.org

On Wed, Aug 20, 2014 at 11:45 AM, Burkhalter, Roger J. <rjb at ou.edu> wrote:

>  We are having drying tubes made by our chemistry department glass
> blower. I have not found a current source of Pyrex straight drying tubes so
> we have them made from quartz glass.
>
> Roger
>
> Sent from my Windows Phone
>  ------------------------------
> From: Vanessa Rhue <vanessa.rhue at gmail.com>
> Sent: ‎8/‎20/‎2014 11:32 AM
> To: Janet Waddington <janetw at rom.on.ca>
> Cc: nhcoll-l at mailman.yale.edu; Burkhalter, Roger J. <rjb at ou.edu>
>
> Subject: Re: [Nhcoll-l] Dusting/powdering skeletal elements prior to
> photographing
>
>   Does anyone have a suggestion on a supplier for the glass receptacle to
> sublimate the NH4Cl?  We've been wanting to get our ammonium chloride set
> up operational again for photographing vertebrate fossils. It was
> recommended that we have the glass receptacle custom made by a local glass
> blower.  Any other suggestions?
>
> In the interim, one of our curator's has used Spotcheck Developer SKD-S2
> manufactured by Magnaflux (see portion of MSDS copied below).  It's a talc
> spray used for spot checking welds.  I wouldn't recommend the product since
> it can be difficult to remove (especially if a fossil has been
> consolidated) and it can be tricky to achieve a light, even coating that
> doesn't obscure the morphology.  A dry rag with water or ethanol has been
> the most effective at removing the residue after photography. Nonetheless,
> it is quick and easy to apply.
>
> SPOTCHECK® DEVELOPER SKD-S2
> 1. IDENTIFICATION
> Company: MAGNAFLUX
> Address: 3624 West Lake Avenue, Glenview, Illinois 60026
> Telephone No.: 847-657-5300 (Off-Hour Emergency Number - CHEMTREC -
> 1-800-424-9300).
> Product Use: Penetrant inspection developer
> Packages: 1 gallon can, 5 gallon pail, 55 gallon drum, aerosol
> NFPA Rating: Health 1, Flammability 3, (aerosol 4), Reactivity 0
> PIN (Canada): UN 1993
> Revision Date: September 5, 2007
> 2. COMPOSITION/INFORMATION ON INGREDIENTS
> Ingredient Wt./Wt.% CAS# TLV PEL LD50 LC50
> 2-propanol 40 – 70 67-63-0 400 ppm 400 ppm 3.6 g/kg(oral/mouse Not
> available
> 2-propanone 10 – 30 67-64-1 750 ppm 750 ppm 6 g/kg (oral/rat) Not available
> Isobutane (propellent –aerosol only)
> 30 75-28-5 Not available 1000 ppm Not available Not available
> Talc 1 - 3 14807-96-6 Not available 2 mg/me Not available Not available
>
>  Cheers,
>
>  VRR
>
> Vanessa R. Rhue
> Assistant Collections Manager
> Department of Vertebrate Paleontology
>
> Natural History Museum of Los Angeles County
> 900 Exposition Blvd
> Los Angeles, CA 90007
> Tel. (213) 763-3248
> Fax (213) 746-7431
> www.nhm.org
>
>
>
> On Wed, Aug 20, 2014 at 7:06 AM, Janet Waddington <janetw at rom.on.ca>
> wrote:
>
>> Aplogies if this went out more than once.  My webmail can be quirky.
>>
>>
>> I agree with Roger, ammonium chloride sublimation can enhance surface
>> details.  It takes some practice and skill to get an even coating,
>> especially with larger objects. (That is an excellent video by the way)
>> One caution - this is a sublimate, not a powder.  In humid conditions the
>> resultant very fine coating will quickly dissolve leaving a fine invisible
>> film of nitric acid on the surface of the object, which could be
>> problematic. On a humid day it sometimes doesn't even make it to the object
>> in solid form.  Just because you can't see it does not mean it has
>> "vanished into thin air". It can also end up in the air of your storage
>> cabinet if it subsequently evaporates off the object.
>>
>> I would worry about not removing it especially if the object is sensitive
>> to acid. If the object is not sensitive to water, it can simply be rinsed
>> with a fine stream or quick dunk into water.  I have used EtOH on specimens
>> that do not like getting wet (e.g. shales) but don't know how effective
>> that really is.
>> Also, be aware that the black coating cannot be completely removed.  It
>> is used to give a uniform background colour so any colouring is not a
>> distraction, and to give contrast to the white coating. But if you plan to
>> use your object for display it might not be as pretty afterwards.
>> That said, sublimation is still a superb tool for studying surface detail
>> and has been used for decades in palaeontology.
>>
>>
>> Janet Waddington
>> Departmental Associate
>> Department of Natural History - Palaeobiology
>> Royal Ontario Museum
>>
>> >>> "Burkhalter, Roger J."  08/20/14 9:11 AM >>>
>>  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:
>> http://www.youtube.com/watch?v=g-FiFtBQthY&list=UUtNiqiI7zdCFS8QGiiYYRfw.
>>
>> Regards,
>> Roger
>>
>> Roger J. Burkhalter
>> Collections Manager, Invertebrate Paleontology
>> Sam Noble Oklahoma Museum of Natural History
>> University of Oklahoma
>> Norman
>> www.snomnh.ou.edu
>> http://commonfossilsofoklahoma.snomnh.ou.edu/
>>
>>
>> From: nhcoll-l-bounces at mailman.yale.edu [mailto:
>> nhcoll-l-bounces at mailman.yale.edu] On Behalf Of Christian Baars
>> Sent: Wednesday, August 20, 2014 3:21 AM
>> To: 'nhcoll-l at mailman.yale.edu'
>> Subject: Re: [Nhcoll-l] Dusting/powdering skeletal elements prior to
>> photographing
>>
>> David,
>>
>> In palaeontology, invertebrate fossils are routinely dusted with ammonium
>> chloride (NH4Cl) 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.
>>
>> 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.
>>
>> 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.
>>
>> Kind regards
>> Christian
>>
>>
>>
>> Christian Baars
>> Senior Preventive Conservator
>> National Museum Cardiff
>> Cathays Park
>> Cardiff CF10 4NP
>> 029 2057 3302
>> christian.baars at museumwales.ac.uk
>>
>>
>>
>>
>> From: nhcoll-l-bounces at mailman.yale.edu [mailto:
>> nhcoll-l-bounces at mailman.yale.edu] On Behalf Of David Katz
>> Sent: 19 August 2014 22:34
>> To: nhcoll-l at mailman.yale.edu
>> Subject: Re: [Nhcoll-l] Dusting/powdering skeletal elements prior to
>> photographing
>>
>> Rachel,
>>
>> 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.
>>
>> 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.
>>
>> ... We'll see.
>>
>>  On Tue, Aug 19, 2014 at 12:50 PM, David Katz > wrote:
>> Hello,
>>
>> 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.
>>
>> 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?
>>
>> Thanks for you input.
>>
>> David
>>
>> --
>> David Katz
>> Doctoral Candidate
>> Department of Anthropology--Evolutionary Wing
>> University of California, Davis
>> Young Hall 204
>>
>>
>>
>> --
>> David Katz
>> Doctoral Candidate
>> Department of Anthropology--Evolutionary Wing
>> University of California, Davis
>> Young Hall 204
>>
>>
>>
>>
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>
>
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