If Evelyne is saving slag micrographs as grey-scale JPG's of 150 kb,  
then these must be reflected light images only.  What I had in mind  
was a more comprehensive teaching collection of annotated colour  
images in both reflected and transmitted light that would provide for  
a single frame (a) both PPL and XPL images in transmitted light; (b)  
at minimum, PPL in reflected light, augmented for anisotropic opaque  
minerals (like haematite) with two XPL images, one rotated 90 degrees  
from the other and (c) where appropriate (as in distinguishing  
fayalite and hercynite in reflected light) PPL and differential  
interference contrast images side by side.  These would be augmented,  
where appropriate, by microprobe data on individual phases (since the  
reflectivity of some common slag-forming minerals like magnetite  
varies greatly with solid solution of other elements), microhardness,  
and perhaps backscattered SEM images (which can look different from  
optical images because of atomic number contrast).  This teaching  
collection would be restricted to slags, refractories and partly  
reduced ores, and be explicitly modelled on the approach used by Paul  
Duller and Rob Ixer in their colour atlas of  ore minerals - i.e.  it  
would show how to identify particular minerals found in these  
materials (including corrosion products), and also to show specific  
associations of minerals that are commonly encountered in both  
ferrous and non-ferrous archaeometallurgy.  It  would be distributed  
on CD/DVD for better image quality than is currently feasible through  
the web.

Since this is rather different in scope from what Evelyne proposes, I  
view the two projects as complementary. We'll continue our efforts to  
find financial support for a slag atlas, which would be a  
collaborative and open-ended venture - a sort of Wikipedia for  
prehistoric and historic slag analysis! We (myself and my graduate  
students) will be very interested in hearing from those who have good  
examples to contribute.

Dave Killick

On May 1, 2006, at 7:47 PM, Evelyne Godfrey wrote:

> Hi again,
>
> With regard to images: we can provide 14 Gb of space for the  
> database for now, with a limit of around 2 Mb of space per entry,  
> so that would accommodate 7,000 entries.
>
> The quality and quantity of the images will be decided by the  
> contributor: you could, for example, choose to upload one ok  
> quality macro photo of the object at around 800 kb, plus one higher  
> quality micrograph of the sample section at 1.2 Mb; so your total  
> database entry would be two images, equaling 2 Mb.
>
> I've been saving ancient slag micrographs as grey-scale JPGs of  
> around 150 kb each, and the resolution is perfectly fine for  
> interpretation, especially for on-screen reference, which is what  
> the database is designed to provide. So in a 2 Mb entry, I could  
> upload a dozen slag microstructure images.
>
> There are a lot of problems with promising to provide CDs.....apart  
> from time/cost burning and mailing out the things, they will keep  
> getting out of date with a database that continually has entries  
> added. But most of all, there are copyright issues: the images on  
> the database, and all related uploaded material, will remain  
> copyright of the contributor. Once something is burned onto a CD, a  
> second party has become a 'publisher', and they would need to get  
> permission from each individual contributor to copy and re- 
> distribute their data. So we won't be making CDs; if you want  
> higher resolution copies of the images, you would have to contact  
> the contributor directly. There are fields in EMMA for  
> "Contributor", "Published (yes/no)", and "Reference".
>
> Compositional analyses: spreadsheet lists of numerical, elemental  
> data on the thousands of metal artefacts that have been generated  
> over the years don't present a data storage problem.... if all you  
> have is a verbal description of the object and the analytical data  
> in Excel for example, that might amount to just 50 kb of data. So  
> descriptions plus compositional analysis of 80,000 artefacts could  
> be accommodated in 4 Gb of space.... or less, if there aren't  
> separate speadsheets. EMMA has the facility to accept Excel files,  
> Word docs, or PDF's attached to a verbal description entry (i.e.  
> you don't need to have a picture file, although of course a picture  
> is what ideally would be preferred).
>
> So I guess the funding resources question is not about numbers of  
> objects or storage space really, but about data-entry time. Our  
> student aide here will scan hard copy submissions and upload, but  
> of course he/she will have to be provided with the descriptive  
> information to enter (e.g. object from which the sample was taken,  
> material, date, provenance, etc). What we could look at for the  
> future would be some scheme of data-entry grants to incorporate  
> existing collections into EMMA.... as with the long-term storage  
> and migration of digital data, this is a general Information  
> Science matter really.....
>
>
> Cheers,
>
>
> Evelyne
>
>
>
>
>
> ++++++++++++++++++++++++++++++++++
>
> Evelyne Godfrey,
> Assistant Professor of Conservation,
> Department of Historic Preservation,
> University of Mary Washington,
> 1301 College Avenue,
> Fredericksburg, Virginia, 22401-5300 USA
>
> Office: 121 Combs Hall
> Tel: 540-654-1312   Mobile: 540-429-3767
>
>
>>>> [log in to unmask] 5/1/2006 11:03 AM >>>
> Dear Evelyne,
>
> Not to be downbeat about web resources of archaeometallurgy,  
> especially
> images of microstructures, but the expanding activity worldwide in  
> this
> field means that the number of compositional analyses and images  
> is, by
> any standards, huge. From Europe, including Russia and European CIS
> countries there must be upwards of 80,000 analyses of Bronze Age
> metalwork alone. A current publication project which will collate all
> available analyses of Early Bronze Age metalwork from the British  
> Isles
> will have almost 2,000 analyses. While metallographic data are much
> scarcer I have probably some 3,000 metallographic samples from  
> European
> prehistory in my own collection. This is on my mind at the moment as a
> change in personal circumstances means I have to draw up a new  
> will, and
> my will contain my wishes for the future of these samples and  
> associated
> data and images. One thing is certain is that the primary archaive is
> the samples themselves and hard copies of data and photographs so  
> as not
> to be overreliant on the continuing forward compatibility of database
> software. Plus, I simply do not have the resources to digitise all  
> this
> - does anybody.
> Yours
> Peter Northover
>
> -- 
> Dr Peter Northover,
> Materials Science-Based Archaeology Group,
> Department of Materials, University of Oxford
> Tel +44 (0)1865 283721; Fax +44 (0)1865 841943 Mobile +44 (0)7785  
> 501745
> e-mail [log in to unmask]