Dear Chris,

The list has provided you with some excellent advice.  i am skeptical that this will be very interesting in the long run, but that is exactly what makes it interesting to do now! I wrote an entire MS thesis after a professor (like me) told me (as a student like you) that some technical study of historic ceramic wouldn't work.  It worked fine and was interesting.  He was wrong.  I may very well be wrong.

I would add this advice for you-
The standardization of color is critical in industrial pottery manufacture.  Consistent color is required for matching sets of tableware.  Those that came from the kiln whole, but slightly off, were sold as seconds, thirds, fourths, or even fifths or sixths.  Consumers ideas about the closeness of color matching changed over time.

Once you understand this, you can expect that the industrial process engineers that work with ceramic have probably used tools like these for many decades.  While antique collectors will swear to you that they can tell the difference in two Spode china plates that were fired with North Sea Gas vs. gas from the continent, engineers tend to be more data driven.

I expect that if you dig into the ceramics engineering literature, you will find some comparative data on the variability of color by kiln load by factory.

I don't think IUP has any engineering faculty.  You could get advice by contacting Dr. William Carty, Ceramic Engineering Program Chair and Professor of Ceramic Engineering at Alfred University in New York.  He would probably be able to direct you to someone who knows that part of the business.
http://engineering.alfred.edu/facultyandstaff/
Be sure to explain your research question by email, since most engineers and materials scientists that work in ceramics can study everything from superconductors to nanoscale glass!

Cheers,
Tim


On Feb 20, 2012, at 2:39 PM, John Chenoweth wrote:

> Dear List,
>  
> A friend just pointed this thread out to me.  I’m sorry I haven’t chimed in earlier.
>  
> As it happens, I’ve just been working on this question over
> this winter, spending some time collecting about 2,000 points of data with a
> spectrophotometer on cream, pearl and whitewares.  
>  
> Spectrophotometers are much like colorimeters, but whereas
> colorimeters simplify color to tristimulus values (L*a*b* values often, akin to
> hue, chroma, and value that we all know from Munsell) spectrophotometers
> capture the full spectrum of reflectance at each wavelength.  These can produce tristimulus values through
> a simple conversion, but the latter are not as accurate because of the
> phenomenon of “metamerism” in which two different colors look the same (i.e.
> produce exactly the same colorimeter results) as a result of the light used to
> examine them.
>  
> I obtained a portable spectrophotometer that was extremely
> easy to use, although its cost is prohibitive for normal analysis.  That shouldn’t be an issue, really, since I
> don’t think the goal of this work will be everyone using machines to identify
> the color of every ceramic: rather, we need a better understanding of the
> actual variations of color present and some statistical analysis that can point
> us to how to deal with that variation.  So, for instance, we can ask if divisions into cream, pearl, and white
> are “real” and what kind of margins of error there are in these determinations.
>  
> In addition to the divisions (or lack thereof) of cream,
> pearl, and whitewares, I’ve been looking at the question of if metamerism is an
> issue, and how much of an issue (we never see people discuss the conditions
> under which they make their identifications, do we?  Yet artificial f. natural light makes a huge
> difference in appearance!).  These values
> can also be converted to precise Munsell values (no margins of error between
> the chips; these are mathematically produced so you get values like 3.4Y
> 8.9/1.71), so that we can consider earlier attempts to define ceramic color
> (but without the well-known problems of Munsell, such as source-light variation
> and large differences between each individual’s determinations).  Also, we know that color can vary across vessels,
> yet we haven’t quantified by how much.
>  
> Of course, George Miller’s comments are very central to
> this discussion (not surprisingly!).  I
> think, as he will probably agree, the question of defining a “master” value for
> each of these types is probably not going to happen: as he points out the
> potters all did different things, resulting in a range of values.  Ultimately, Carl Steen is also right that
> many other factors go into determinations.
>  
> BUT, and here is why I think projects like this are
> worthwhile) we can actually measure most of these factors using repeatable (I’m
> too much of a post-modernist to say “objective”) procedures and equipment:
> spectrophotometers, glossimeters, durometers, etc.  We all make all these determinations all the
> time, but, as Bill Liebeknecht points out with his yellowware story, we aren’t
> always sure of what we’re talking about.  Fifty years of experience can produce consistency, but it can’t
> reconcile with another person’s fifty years of experience.  The conversation has been too long about “is
> that yellow enough to be…” and can now be a discussion of what a particular
> level of yellow (repeatably measured) means.  This doesn’t solve our problems, but it means we’re speaking the same
> language when we have our discussions, at least.
>  
> Finally, I’m sorry to say that all this is prologue,
> since I collected the data in question two months ago, but have yet to finish
> the statistical analysis (must meet up with a friend who is better at
> multivariate stats than me!).  At first
> glance, the data rather suggests that there are no clear distinctions between
> cream, pearl, and whitewares on the basis of color alone, but the issue of
> exactly how meaningful those classifications are is yet to be settled.
>  
> I look forward to reporting the results soon!
> Best,
> John
> ----------
> John M. Chenoweth, PhD, RPA
> Post-Doctoral Fellow, IHUM
> Stanford University
> [log in to unmask]
> 
> 
> 
> 
> ________________________________
> From: sent <[log in to unmask]>
> To: [log in to unmask] 
> Sent: Monday, February 20, 2012 9:20 AM
> Subject: Re: [HISTARCH] Colorimeter for ceramics
> 
> All depends on the questions you wish to ask.
> Once ceramics enter secondary contexts these sort of distinctions become 
> less important
> As they decline in importance with context change then essential material 
> attribute description becomes more important.
> 
> Conrad Bladey
> 
> -----Original Message----- 
> From: Bill
> Sent: Monday, February 20, 2012 8:25 AM
> To: [log in to unmask]
> Subject: Re: Colorimeter for ceramics
> 
> I agree with Carl.  When looking at an assemblage you should be more
> concerned with the larger picture.  What are the other ceramics found in
> association.  You can take a piece of white paper and layout the pearlware
> and creamware sherds and make divisions rather quickly.  Creamwares or CC
> wares were being produced in Trenton as late as 1905, specifically
> chamberpots.  This just goes back to my point about the association of the
> wares in context.
> 
> Bill Liebeknecht, MA RPA
> Hunter Research, Inc.
> 
> -----Original Message-----
> From: HISTORICAL ARCHAEOLOGY [mailto:[log in to unmask]] On Behalf Of Carl
> Steen
> Sent: Monday, February 20, 2012 7:59 AM
> To: [log in to unmask]
> Subject: Re: Colorimeter for ceramics
> 
> Glaze tint varies for many reasons. While early cream and pearlware do have
> distinctive colors, this varies due to a number of factors ranging from the
> potters glaze formula, and firing conditions, to use and deposition history.
> Also, don't forget that blue and cream tinted wares were intentionally
> produced throughout the 19th and 20th centuries. I can't tell you how many
> times I have seen single sherds of creamware or pearlware identified in
> otherwise late contexts. Glaze tint is only one of many characteristics
> (density, firing, decoration, vessel form etc) you have to look at to
> accurately date a vessel or sherd, so micro-analysis of glaze tint is
> something I wouldn't get too hung up on, personally. But do keep us apprised
> of your results! Carl
> 
> 
> 
> 
> Carl Steen
> 
> 
> 
> 
> -----Original Message-----
> From: Conrad Bladey <[log in to unmask]>
> To: HISTARCH <[log in to unmask]>
> Sent: Mon, Feb 20, 2012 7:49 am
> Subject: Re: Colorimeter for ceramics
> 
> 
> Color is often formed my after market environmental conditions I would
> suggest
> chemical analysis more helpful but that too. Would be modified by soils and
> heat
> etc.
> 
> Conrad
> 
> ----------------------------
> This message has been written by fingers that are too big!
> 
> On Feb 20, 2012, at 6:56 AM, Bob Genheimer <[log in to unmask]>
> wrote:
> 
>> Chris
>> 
>> I just completed a large scale examination of Cincinnati-area yellow ware,
> and
> utilized a full-color Munsell book(s) for color comparison.  The Munsell is
> not
> fully adequate, because there is still a small range of color within each
> chip
> match.  I recognized that a colorimeter was the way to go, but taking
> hundreds
> of vessels to the colorimeter was just not an option.  I would be very
> interested in comparisons of colorimeter data with Munsell matches.
>> 
>> Bob Genheimer, RPA
>> George Rieveschl Curator of Archaeology
>> Cincinnati Museum Center
>> 1301 Western Avenue
>> Cincinnati, Ohio 45203
>> 513-455-7161 office
>> 513-846-4898 mobile
>> 513-455-7169 fax
>> 
>> 
>> -----Original Message-----
>> From: HISTORICAL ARCHAEOLOGY [mailto:[log in to unmask]] On Behalf Of
> Christopher Nicholas Marini
>> Sent: Sunday, February 19, 2012 3:47 PM
>> To: [log in to unmask]
>> Subject: Colorimeter for ceramics
>> 
>> Dear List,
>> I am a graduate student at Indiana University of Pennsylvania and I am
> currently looking to begin work on my master's thesis. The project I am
> considering involves using a device called a colorimeter, which measures
> color,
> to develop a scale for identifying ceramics, most notably creamware,
> pearlware,
> and whiteware, as I have had personal experience with the difficulty in
> identifying these artifact types.
>> 
>> I have done some research into this topic, but am unsure whether or not
> anyone
> else has already attempted it. I have looked through several major journals
> and
> have not found any reference to such a project. If anyone knows of work of
> this
> type that has been done, please let me know of it so that I may incorporate
> it
> into my project or switch thesis topics.
>> 
>> Thank you for your time,
>> Chris
>> 
>> 
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