1_README.TXT

The Effect of Selected Cleaning
Techniques on Berkshire Lee Marble:
A Scientific Study at Philadelphia City Hall


By Victor G. Mossotti, A. Raouf Eldeeb, Terry L. Fries, 
Mary Jane Coombs,
U.S. Geological Survey;

Virginia N. Naude',
Norton Art Conservation, Inc;

Lisa Soderberg,
Vitetta Group;

and

George Wheeler,
Metropolitan Museum of Art, New York


Professional Paper 1635

2002

U.S. Department of the Interior 
Gale A. Norton, Secretary 

U.S. Geological Survey 
Charles G. Groat, Director 

QUICK START

For those already familiar with Adobe Acrobat Reader and 
who have version 5.0 or greater of this program on their 
computer, go directly to the file pp1635.pdf.  


CONTENTS

This CD-ROM contains Portable Document Format (.pdf) files 
for the main text of the report (pp1635.pdf) as well as the 
individual folders of images, data tables, and software.

Files:
-- 1_README.TXT - this text file in ASCII format
-- pp1635.pdf - The text, figures, and tables for this 
     report presented in the form of an electronic "book" 
     using Adobe Acrobat Reader.
-- Autorun.inf and usgsid.ico - display files for Windows

Folders:
-- Acrobat - folder containing installer software
-- figures - A folder containing the individual graphic 
     files used in this paper.  These 156 files were made 
     from the authors' 300-dots-per-inch (dpi) .tif images 
     by saving them as 300-dpi PDFs using zip compression.  
     This technique allowed compression of the original 971 
     MB of data down to 198 MB with no data-quality loss.  
-- images - A folder containing three sub folders of 
     images:
     --core_surface_photos - .jpg files
     --pch_facade_and_detail - .jpg files
     --sem_cut_images - image files generated from the 
          scanning electron microscope 
-- index folder and index.pdx - items used for the Search 
     feature in Acrobat Reader
-- programs - A folder containing DOS software used to 
     analyze the images (EDGE.EXE, PROFILE.EXE, 
     SEM2BIN.EXE, and SHOWPIX.EXE)
-- tables - A folder containing the 42 tables used in this 
     paper. Data are presented in both comma-delimited 
     (.csv) and Microsoft Excel (.xls) formats


Three kinds of graphics files are located in the "images" 
folder.  Subfolders consist of:  "core_surface_photos," 
"pch_facade_and_detail," and "sem_cut_images."  The 
"core_surface_photos" subfolder contains 155 images in .jpg 
format.  The "pch_facade_and_detail" subfolder contains 11 
photographs of the facade and detail of Philadelphia City 
Hall in .jpg format.  These are each about 3072 by 2048 
pixels (six megapixels) and are numbered PCH01.jpg through 
PCH11.jpg.  PCH09.jpg was used for the label and PCH11.jpg 
was used for the cover of this CD-ROM.  The 
"sem_cut_images" subfolder contains images generated from 
the scanning electron microscope.  For information on 
viewing files from this folder, refer to 

Mossotti, V.G., Eldeeb, A.R., and Oscarson, Robert, 1998, 
     MORPH-I (Ver. 1.0), a software package for the 
     analysis of scanning electron micrograph (binary 
     formatted) images for the assessment of the fractal 
     dimension of enclosed pore surfaces: U.S. Geological 
     Survey Open-File Report 98-248, 74 p. 
     [URL http://geopubs.wr.usgs.gov/open-file/of98-248]

Four programs are contained in the "programs" folder:  
EDGE.EXE, PROFILE.EXE, SEM2BIN.EXE, and SHOWPIX.EXE.  These 
programs are part of a software package for the analysis of 
scanning-electron-micrograph (binary-formatted) images for 
the assessment of the fractal dimension of enclosed pore 
surfaces.  


SYSTEM REQUIREMENTS

This CD-ROM (pp1635) was produced in accordance with the 
ISO 9660 Level 2 standard and Apple Computer's(1) 
hierarchical file system (HFS) standard.  The data and text 
on this CD-ROM require either a UNIX(2) system-based or 
Linux(3) workstation, Macintosh or compatible computer, or 
an IBM(4) or compatible personal computer, all equipped 
with a CD-ROM drive and a color monitor that can display 
256 colors (16.7 million recommended).  

The PC should have:
-- Intel(5) Pentium(5) or compatible processor-based 
     personal computer
-- Microsoft(6) Windows 95 OSR 2.0, Windows 98 SE, 
     Windows Millennium, Windows NT(6) 4.0 with Service 
     Pack 5, Windows 2000, or Windows XP
-- 64 MB of RAM

The Macintosh should have:
-- PowerPC(1) processor
-- Mac OS software version 8.6, 9.0.4, 9.1, 9.2, or OS X; 
     some features of Acrobat 5.0.5 may not be available 
     for OS 8.6 and OS X due to OS limitations.
-- 64 MB of RAM

UNIX
-- Almost any UNIX system-based or Linux workstation 
     can read these files.

All platforms
-- Adobe(7) Acrobat(7) Reader 5.0 or higher (Acrobat Reader 
     5.0.5 for Windows and Macintosh are provided on this 
     CD-ROM in the "Acrobat" folder).  The PDFs can be read 
     with Acrobat 4 but without the re-wrap feature.

Optional software
-- Microsoft Excel(6) for reading the .xls files
-- Other spreadsheet or database-management software that 
     can read comma-separated-value (.csv) files

Optional hardware
-- An IBM or compatible personal computer that can run 
     in DOS mode to run the .exe files in the "programs" 
     folder


TO GET STARTED:

On a Macintosh, double-click on the CD-ROM (pp1635) icon 
and double-click on the file pp1635.pdf to open it with 
Acrobat Reader.  

On a PC system with Windows, the disc pp1635 should open 
automatically.  If not, double-click on My Computer, 
double-click on the CD-ROM (pp1635) icon and double-click 
on the file pp1635.pdf to open it with Acrobat Reader.  

On a UNIX or Linux workstation, mount the CD-ROM. If you 
are unsure about the process of mounting CD-ROMs on the 
workstation, see your system administrator for 
instructions.  Once the CD-ROM is mounted, use Acrobat 
Reader to open the file pp1635.pdf.


PORTABLE DOCUMENT FORMAT (PDF) FILES

Using Adobe Acrobat Reader, you can view, search, and print 
copies of the PDF documents in this report.  The main 
document PDF, pp1635.pdf, opens with "bookmarks" displayed 
that allow you to choose among the sections of the text and 
the figures.  The "Acrobat" folder contains installers for 
Adobe Acrobat Reader 5.0 for both Windows ("PC" subfolder) 
and Macintosh ("Mac" subfolder).  You can use the 
installers provided on this CD-ROM, or download the latest 
version of Adobe Acrobat Reader free via the World-Wide Web 
from the Adobe home page 
at 

     http://www.adobe.com/products/acrobat/readstep.html.  

Within the text, there are hyperlinks (or "hot links") 
built into each entry of the Contents and into each mention 
of a figure, table, section, appendix, reference, or 
footnote.  Hyperlinks become apparent as you hover over 
them with the mouse, as the cursor changes to a pointing 
finger.  As you read, you can use the hyperlinks by 
clicking on them with your mouse and you will be moved to 
that view.  To get back to the previous view, use the 
"back" button on the menu bar at the top of the Acrobat 
screen or press Alt + left-arrow (Windows) or Command + 
left-arrow (Macintosh).  World-Wide-Web URLs are also 
hyperlinks; clicking on them will launch your browser and 
you will be taken to that Web site.

This CD-ROM contains a full-text index ("index.pdx" and 
associated files in the "index" folder) that is for use in 
searching the PDF file on this disc for words or sets of 
words using the Search tool in Acrobat Reader.  To make 
best use of this CD-ROM, you will need to develop some 
familiarity with Acrobat Reader; an on-line guide is 
available within Acrobat Reader under "Help."  


ABSTRACT

This report describes a scientific investigation of the 
effects of eight different cleaning techniques on the 
Berkshire Lee marble component of the facade of the East 
Center Pavilion at Philadelphia City Hall; the study was 
commissioned by the city of Philadelphia. The eight 
cleaning techniques evaluated in this study were power wash 
(proprietary gel detergent followed by water rinse under 
pressure), misting (treatment with potable, nebulized water 
for 24-36 hours), gommage (proprietary Thomann-Hanry low-
pressure, air-driven, small-particle, dry abrasion), 
combination (gommage followed by misting), Armax (sodium 
bicarbonate delivered under pressure in a water wash), JOS 
(dolomite powder delivered in a low-pressure, rotary-vortex 
water wash), laser (thermal ablation), and dry ice 
(powdered-dry-ice abrasion delivered under pressure).

In the quasi-experimental design, a control sample, taken 
from an area of stone protected by epoxy adjoining an 
unprotected test area, was simultaneously cored with the 
test sample. In our study, approximately 160 cores were 
removed from the building for laboratory analysis. As a 
basis for differentiating the various cleaning techniques, 
we measured the changes in the structural properties of the 
stone on the microscale (0.1-100 micro meters), and in the 
esthetic features of the stone on the mesoscale (0.1-5 mm) 
and macroscale (greater than or equal to 0.5 cm), caused by 
each of the cleaning techniques.

The spatial distribution of particulate matter 
and salts on adjacent control and test surfaces was 
measured by electron microscopy on the microscale and by 
optical reflectance on the mesoscale to macroscale (0.1-20 
mm). We developed a computer program to analyze 
scanning-electron-micrograph (SEM) images for the fractal 
dimension and other morphologic parameters of the stone 
surface; the fractal dimension is a factor in the surface-
roughness test. The program also computed the near-surface 
fracture density of the stone.

An analysis of more than 1,100 samples cut from the cores 
provided a statistical basis for crafting the essential 
elements of a reduced-form, mixed-kinetics conceptual model 
that represents the deterioration of calcareous stone in 
terms of self-organized soiling and erosion patterns. This 
model, in turn, provided a basis for identifying the 
variables that are affected by the cleaning techniques and 
for evaluating the extent to which such variables influence 
the stability of the stone. The  model integrates the 
mutual dependence of processes controlling the primary 
deposition of soiling agents, the secondary mobilization of 
transportable materials, and the permanent alteration of 
the stone through critical feedback paths in the model 
system.

The model recognizes three classes of variables that may 
influence the soiling load on the stone, including such 
exogenous environmental variables as airborne moisture, 
pollutant concentrations, local aerodynamics, and so on, 
and such endogenous stone variables as surface chemistry 
and microstructure (fracturing, roughness, and so on). Our 
study showed that morphologic variables on the mesoscale to 
macroscale are generally not affected by the choice of a 
cleaning technique. For example, surface-recession tests 
indicate that differences in mass loss from technique to 
technique are virtually inconsequential over the long term. 
The model also explains the spatial distribution of 
particulate matter and salts over the building by the 
action of water on the stone surface. According to this 
mechanism, the soiling pattern on the building is 
controlled mainly by the macromorphology and orientation of 
the stone. Thus, the long-term soiling pattern on the 
building is independent of the cleaning technique applied.

This study also showed that micromorphologic variables are 
differentially affected by the various cleaning techniques. 
Although the extent to which surface microstructure and 
microchemistry influence the soiling load requires further 
study, we assumed in our evaluation that the long-term 
esthetic and structural properties of the stone are closely 
related to the lateral and vertical distribution of 
particulate matter and salts and to the mechanical bonding 
between calcite, phlogopite, and dolomite grains in the 
matrix. Contrary to our original conjecture, we found no 
evidence that soluble salts play a significant role in the 
deterioration of Berkshire Lee marble. Although salts were 
evident in cracks and fissures of the heavily soiled stone, 
such salts did not penetrate the surface to a depth of more 
than a few hundred micrometers.

Interestingly, we noted that the strength of the relation 
between the fracture density and the surface roughness was 
distinctly sensitive to the cleaning technique used, and so 
we used this relation as a measure of the marginal ability 
of each technique to clean the stone without causing 
collateral damage to the surface. Thus, the criteria used 
to differentiate the cleaning techniques were ultimately 
based on the ability of each technique to remove soiling 
without altering the texture of the stone surface. This 
study identified both the gommage and JOS techniques as 
appropriate for cleaning ashlar surfaces and the 
combination technique as appropriate for cleaning highly 
carved surfaces at the entablatures, cornices, and column 
capitals.


ACKNOWLEDGMENTS

This research was supported by the U.S. National Park 
Service (NPS)'s National Center for Preservation Technology 
and Training, the Philadelphia Historical Society, and the 
city of Philadelphia; development of the SEM image-analysis 
software (MORPH-I and MORPH-II) was specifically supported 
by the NPS. Susan Sherwood assisted in organizing the 
multidisciplinary project team of preservation architects, 
conservators, and scientists. We also thank Chandra Reedy, 
ElizaBeth Bede, Susan I. Sherwood, and Richard Tosdal for 
their reviews of the manuscript.


FOR SALE BY:

USGS Information Services
Box 25286
Denver Federal Center
Denver, CO  80225
Telephone: (888) ASK-USGS

The bibliographical reference for this publication is:

Mossotti, V.G., Eldeeb, A.R., Fries, T.L., Coombs, 
     Mary Jane, Naude', V.N., Soderberg, Lisa, and Wheeler, 
     G.S., 2002, The effect of selected cleaning techniques 
     on Berkshire Lee marble:  a scientific study at 
     Philadelphia City Hall:  U.S. Geological Survey 
     Professional Paper 1635 (CD-ROM).

ISBN 0-607-96243-7

This report and any updates to it are available on line at
http://geopubs.wr.usgs.gov/prof-paper/pp1635/

     Library of Congress Cataloging-in-Publications Data

The effect of selected cleaning techniques on Berkshire Lee 
  marble [computer file] : a scientific study at 
  Philadelphia City Hall / by V.G. Mossotti ... [et al.].
  1 computer optical disc ; 4 3/4 in. -- (Professional 
  paper ; 1635)
  Title from disc label.
  Audience:  Geologist, monument curators.
  Summary:  A scientific investigation of the effects of 
eight different cleaning techniques on the Berkshire Lee 
marble component of the facade of the East Center Pavilion 
at Philadelphia City Hall.  The eight cleaning techniques 
evaluated were power wash, misting, gommage, combination, 
Armax, JOS, laser, and dry ice.
  ISBN 0-607-96243-7
  1. Building stones--Cleaning--Software.  2. Marble--
Cleaning--Software.  I. Mossotti, V. G. II. U.S. Geological 
Survey Library.  III.  Series:  U.S. Geological Survey 
professional paper ; 1635.
TH5520
691--dc13
                                                 2001016528
                                                        CIP


DISCLAIMERS

This Compact Disc Read-Only Memory (CD-ROM) publication was 
prepared by an agency of the U.S. Government.  Neither the 
U.S. Government nor any agency thereof, nor any of their 
employees, makes any warranty, expressed or implied, or 
assumes any legal liability or responsibility for the 
accuracy, completeness, or usefulness of any information, 
apparatus, product, or process disclosed in this report, or 
represents that its use would not infringe on privately 
owned rights.  Reference therein to any specific commercial 
product, process, or service, by trade name, trademark, 
manufacturer, or otherwise does not necessarily constitute 
or imply its endorsement, recommendation, or favoring by 
the U.S. Government or any agency thereof.

Although all data and software published on this CD-ROM 
have been used by the U.S. Geological Survey (USGS), no 
warranty, expressed or implied, is made by the USGS as to 
the accuracy of the data and related materials and (or) the 
functioning of the software.  The act of distribution shall 
not constitute any such warranty, and no responsibility is 
assumed by the USGS in the use of these data, software, or 
related materials.

Any use of trade, product, or firm names is for descriptive 
purposes only and does not imply endorsement by the U.S. 
Government.


REGISTERED TRADEMARKS

(1) Apple Computer, Inc.
(2) The Open Group
(3) Linus Torvalds
(4) IBM Corp.
(5) Intel Corp.
(6) Microsoft Corp.
(7) Adobe Systems, Inc.