X-ray Fluorescence Analysis of Iron Gall Inks, Pencils and Coloured Crayons
Oliver Hahn, Birgit Kanngießer and Wolfgang Malzer
The qualitative and quantitative investigation of historical writing materials using micro X-ray fluorescence analysis (micro-XRF) a suitable method for obtaining 'composition fingerprints' of different inks and coloured crayons. The quantitative analysis is based on a model that lakes into account the heterogeneity and the layer structure of historical samples. Starting from these
imposition fingerprints, it is possible to distinguish between different iron gall inks used by an individual artist in order to establish a chronology of their use and, furthermore, to date unknown fragments that have not been integrated into the ocuvre of an artist until now. Qualitative and quantitative analyses of'several manuscripts of Johann Wolfgang von Goethe clarify the chronology within the genesis of these works. Investigation of Achim von Amim's manuscript
'Sludien zu Xalurwisscuschaften' indicated that various degradation mechanisms of iron gall inks could also be related to different inorganic compositions. Further measurements on coloured crayons in Friedrich Nietzsche's notebooks reveal thai it is possible to distinguish between different notes written by Nietzsche and his successors. Finally the analyses of two different pencils from Goethe's work shows that it might be possible to distinguish between sketches completed before and after 1800.
INTRODUCTION
Archaeological and art historical research is usually concerned with questions of origin, dating or attribution of cultural objects. Stylistic and art historical considerations n combination with the investigation of technological treatises and recipes can answer many questions, but in several cases the analysis of the physical properties and the chemical composition of the artifacts is essential. Investigations concerning the chemical composition of cultural objects are also important for their conservation. Not only is it fundamental for archaeometric studies to document the current state of cultural artifacts, as subsequent restoration processes may change this state — for example, change of chemical composition of iron gall inks during washing of manuscripts — but in general it would be advisable to supervise restoration processes by noninvasive analytical methods. The authors started is kind of control with mass deacidification methods. A particular requirement for the investigation of cultural and historical objects is the use of techniques that are non-destructive or only need minimal sampling. The methods should also be fast, easily accessible, versatile, sensitive, and multi-elemental [1 ]. As X-ray fluorescence analysis
(XRF) meets most of these requirements, analyses of objects of artistic or archaeological value by
XRF, total reflection X-ray fluorescence analysis (TXRF), synchrotron X-ray fluorescence micro analysis (SYXRF) and also by particle induced X-ray emission analysis (PIXE) [2] are fairly common. The importance of X-ray techniques for archaeometric investigations has increased immensely in recent years. Indeed, they represent one of the most suitable ways to obtain qualitative and quantitative information on many different materials, such as pigments, metals, glass, or even organic materials like ivory and bones. Numerous publications (for example, the special millennium edition of the journal X-Ray Spectrometry on cultural heritage) emphasize their relevance [3, 4]. This article presents the application of XRF to the study of different writing materials, namely iron gall inks, pencils and coloured crayons, which will be described briefly below.
Iron gall ink
A mixture containing iron salts and tannins to prepare a writing material has been used since antiquity. Although carbon inks were widely used from the third millennium B.C., the colouring power of an iron gallate complex had been known for a long time. In the second century B.C.
, Philo

of Byzantium, for instance, published a recipe for an invisible ink that was prepared with the extract of gall nuts [5]. The cipher becomes visible after treatment with iron salts. Pliny mentions the reaction as an indicator for the detection of iron salts as an adulteration of alum [6] and describes shoemakers rubbing freshly tanned boots with atramentum to stain them black [7]. Atramentum is iron vitriol (iron sulphate). From the fifteenth century onward, it was also a popular drawing ink, favoured by many artists like Rembrandt and Lorrain. Due to the development of various useful synthetic inks, which were based on aniline dyes, iron gall ink lost its importance during the nineteenth century.
Iron gall ink is produced from four basic ingredients: galls, vitriol, gum arabic as a binding medium, and an aqueous medium such as wine, beer or vinegar. By mixing gallic acid with iron sulphate, a water-soluble ferrous gallate complex is formed. Due to its solubility, the ink penetrates the paper surface, making it difficult to erase. When exposed to oxygen, a ferric gallate pigment is formed.
This complex is not water-soluble, which contributes to its indelibility as a writing ink. Normally, the presence of oxygen leads directly to the formation of the ferric gallate pigment when mixing gallic acid and iron sulphate. Gum arabic acts like a suspension agent tor the insoluble pigment particles. It also modifies the viscosity of the ink. Due to the variety of different recipes and the natural origin of these different materials, there is a wide range of different components and impurities in historic iron gall inks that may cause a diversity of distinguishable degradation mechanisms involving changes in colour, occasionally resulting in iron gall ink corrosion [8].
Vitriol, the main inorganic compound of iron gall inks, was obtained from different mines and by various techniques [9]. Therefore the iron sulphate is contaminated to varying degrees with many other metals like copper, aluminium, zinc and manganese, which do not contribute to colour formation in the ink solution but possibly change the chemical properties of the inks. In Goslar
(Germany), for instance, a large concentration of natural vitriol supplied a great deal of the Middle
European market [10], Liquid was collected in large iron pans as it trickled out of the rock in mine shafts. Crystallized salts would form after the water had evaporated. The liquid was also collected in a barrel, and vitriol crystals developed on a rope hung into the barrel as the water evaporated. To increase the iron sulphate content, scrap iron was added to the solution. Iron sulphate that contained aluminium as the primary impurity could also be obtained as a by-product from alum manufacturing.
Pencils
The natural product graphite has been known since time immemorial. The name derives from graphein, the Greek term for 'write' or 'sketch'. But the Latin term plumbago caused confusion between the material, graphite, that contains only carbon and the term plumbum, which means lead.
Findings from the fifteenth century provide evidence that pencils made from graphite were used.
The material was cut into rods and preserved in so-called porte crayons. The pencil itself owes its invention to Jacques Louis Conte. He used graphite that was pulverized and purified and then mixed with slip to prepare a writing material of consistent quality. The ratio of graphite to clay defines the characteristics of the writing tool that could be manufactured in a consistent grade. The pencil was patented in 1795 and replaced more and more other writing materials, such as pure graphite [11].
Coloured crayons
Coloured crayons (coloured pencils) are manufactured in a similar way to pencils. The leads of the crayons contain kaolin and inorganic pigments such as Prussian blue, chrome yellow, chrome green, ultramarine, and cinnabar or organic colourants (eosin, Helio fast red). The pigments were wetrefined with kaolin, and then dispersed with tragacanth or similar binding media. This paste is pressed into strands, dried, cut in pieces and, like pencils, furnished with a mixture of wax and fat
[12]. Starting from the recipes it is often not possible to distinguish different crayons by means of

the main colouring pigment, but this can be achieved by investigating different inorganic admixtures.
A FINGERPRINT MODEL
The different chemical composition, which varies remarkably from one ink, pencil or crayon to another, is a characteristic property of different historical writing materials. On the one hand, there are qualitatively distinguishable components or impurities. Pencils and crayons, in particular, reveal different amounts of varying elements. On the other hand, they appear in different quantities [13]. The qualitative and quantitative investigations of the inorganic ingredients, for instance, lead to exact characterizations of the different materials, summarized by means of 'fingerprints'. Based on these fingerprints, it should be possible to date fragments that have not been integrated into the oeuvre of an artist until now. Furthermore, it is possible to study the genesis of manuscripts by separating later corrections and amendments from the first sketch. For a demonstration of the versatility of this fingerprint model the authors published recently the investigation of different Faust manuscripts by Johann Wolfgang von Goethe [14]. The iron gall inks were found to contain iron (Fe), copper (Cu), zinc (Zn) and manganese (Mn) in noticeable quantities; thus, the composition fingerprint is expressed by three relative amounts of weight concentrations of Cu, Zn and Mn in relation to iron (Figure 1). It is obvious that the two manuscripts investigated, which were written with the same ink, belong to the Faust I complex. The iron gall ink used for the Faust II manuscript is a different ink. But the ink used to add some corrections to a Faust I text passage seems to be the same ink used for the writing of Faust II.
Regarding these first samples, it could therefore be assumed that Goethe continued his work on the manuscript of Faust I while writing the second part of his drama.
Finally, this method might permit distinction between original and falsification. Of course, it is not possible to date manuscripts absolutely with this method.
Figure 1 Representative composition fingerprint values W
Mn,
W
Zn
and W
Cu in a ternary diagram obtained from different inks used in 'Faust I + II' by Goethe [14 ] .
However, the analyses show that it is not necessary to perform absolute dating of writing inks to obtain essential contributions to historical or archaeometric research. The fingerprint method relies

on the determination of characteristic elemental compositions in samples. These kinds of investigations are well-established methods for provenance and dating studies of glass objects [15,
16] as well as for the chronological classification of alloys [ 17]. The present micro-XRF measurements for iron gall inks were quantified using the composition fingerprint model, which is based on fundamental parameter procedures leading to the value W i
(relative amount of weight concentration of the element i relative to Fe). The composition fingerprint value W i
mainly involves three different parameters: the experimentally determined transmittance of the entire layered system, the penetration depth of the writing material into the paper (in the case of iron gall inks) and a normalized absorption coefficient, taking into account the matrix composition. The respective calculations are based on a model ink containing a certain amount of iron sulphate as a constant parameter [18]. However, small variations of any other parameters do not essentially affect the value of W i
To further ensure the correctness of this approach, the thicknesses of the ink layer on the paper and in the paper and the thickness of the paper itself were also obtained by performing scanning electron microscopy/energy dispersive X-ray microanalysis (SEM/EDX) on very similar samples. In view of the importance of the mass deposition of the ink (i.e., the amount of ink on the paper in grams of ink per square metre of paper) for the interpretation of W i
it may be emphasized that the influence of the paper background (Figure 2), and therefore the uncertainty of W i increases with decreasing mass deposition of the ink.
INSTRUMENTATION
The paper objects investigated in this study are very fragile and have to be kept in a controlled environment. Therefore they are not movable. The investigations have to take place without taking samples and without touching the surface of the manuscripts (Figure 3). Analyses were therefore carried out with the ArtTAX® mobile energy dispersive micro-X-ray spectrometer (Rontec GmbH,
Berlin, Germany), which consists of an air-cooled low-power molybdenum tube, polycapillary Xray optics (measuring spot size 100 urn diameter) [19], an electrothermally cooled Xflash detector, and a CCD camera for sample positioning. Furthermore, additional open helium purging in the excitation and
Figure 2 Representative XRF spectrum of a historical iron gall ink on rag paper, showing that the paper Packground also contains the same elements as those occurring in the ink. detection paths enables the determination of light elements (11 < Z < 20) without vacuum. The silicon drift detector with high-speed, low-noise electronics permits an energy resolution of 160 eV

for Mn K
α radiation at a count rate of 10,000 cps. It has an active area of 5 mm
2
and an 8 urn-thick
Dura-beryllium window. The geometry between primary beam, sample and detector is fixed at
0°/40° relative to the perpendicular of the sample surface [20]. All measurements were made using a 30 W low-power Mo tube, 45 kV, 600 µA, and with an acquisition time of 12 seconds (live time) to minimize the risk of damage. For better statistics, at least 10 single measurements were averaged for one data point, presented in each of the diagrams in the following discussion.
RESULTS AND DISCUSSION
Results of the application of the fingerprint model are summarized shortly in different sections, each of which takes into account a special point of interest. The first example focuses on conservation aspects concerning iron gall inks by assuming a correlation between ink colour and chemical composition. Further examinations demonstrate archaeometric questions regarding the characterization of distinguishable iron gall inks used by one artist. The last two examples demonstrate the distinction between different red crayons and pencils. Nevertheless, all the analytical results have to be evaluated against historical reflections.
Figure 3 Experimental set-up, showing the measuring head of the portaPle X-ray fluorescence spectrometer at a distance of 0.5 cm above the paper surface.
Achim von Arnim: 'Studien zu Naturwissenschaften'
The influence of the composition on the corrosion of iron gall inks has already been discussed [14].
The manuscript of Achim von Arnim, dating from 1798-1800, contains several notes on lectures about the natural sciences. All lettered folios are bound into one book. The visual characterisation shows that Arnim used a variety of different inks. Some inks are deep black whereas other inks are dark or light brown (Figure 4). Due to the very short genesis of this manuscript, it has to be assumed that differences in colour of the inks are not due to the fact that they aged for different periods of time, but to differences in chemical composition. The measurements with micro-XRF seem to support this

Figure 4 Black and brown inks in 'Studien zu Naturwissenschaften' by Achim von Arnim (GSA
03/354). assumption (Figure 5). It is noticeable that the brown inks contain a high amount of copper (in comparison to iron). It is already known that copper catalyses the oxidative degradation of organic material [21]. So it may be concluded that the brown inks may contain a higher amount of decomposition products. Measurements will be performed using X-ray absoiption near edge structure (XANES) experiments, to elucidate the ratio of Cu(I)/ Cu(II) during the iron gall ink corrosion process. This may contribute to the overall understanding of the iron. gall ink corrosion process [22].
Johann Wolfgang von Goethe: letter to his publisher Johann Christian Kestner (14 April 1773)
Figure 6 shows the X-ray fluorescence spectrum of the original iron gall writing ink in comparison to that of another ink that was used for large-area deletions in the

Figure 6 X-ray fluorescence spectra of two different inks in a letter from Goethe to his publisher
Johann Christian Kestner. The first is the original iron gall ink from 1773 whereas the second was
used for large-area deletions in the letter. letter. Visually, both inks have the same colour, but the XRF analysis shows that the inks are quite different. The presence of chrome in the second ink indicates that it was not applied before the beginning of the nineteenth century, when the use of substances containing chrome (e.g., as pigment) was proposed for the first time (after L.N. Vauquelin had discovered the element chrome in the mineral crocoite in 1797). It may be concluded from this that the deletions were not only done with a different ink but also at least 30 years later. The former assumption that Goethe modified his letter before sending it to Kestner has to be rejected.
Johann Wolfgang von Goethe: two letters to his sister Cornelia
Several early letters from Goethe to Cornelia, mainly written in French, still exist. They survived thanks to Goethe's father, Johann Caspar Goethe, who not only collected these letters but also
'improved' the texts. So the letters contain different corrections and amendments, made by Goethe himself and by his father. For literary historical research it is necessary to distinguish Goethe's amendments from those that were added by his father or by his tutor. Former literary historical research has not considered such distinction sufficiently.
Figure 7 shows representative fingerprint values obtained from different inks from two letters written by Goethe to Cornelia in 1765 and in 1766. The investiga-

Figure 7 Representative composition fingerprint values W
Cu
= (K
Cu
W
Cu
) / (K
Cu
W
Cu
) obtained from different inks from two letters written by Goethe to Cornelia, showing a definite distinction between two main ink types (type I and type II). tions demonstrate a definite distinction between two main ink types (type I and type II). The inks under analysis only contain Cu and Fe in noticeable quantities (with one exception, see data point no. 4). Thus, the composition fingerprint is expressed by the relative amount of Cu in relation to iron, W
Cu
.
The analyses reveal that Goethe mostly used one iron gall ink (type I) for both letters. Two corrections (see data points no. 11 and no. 12) were executed with the same ink and therefore added during the writing process. All the other amendments were done with another ink (type II) at a later date. The results corroborate the literary historical assumption that these amendments were inserted by Goethe's father.
Investigation of coloured crayons in notebooks of Friedrich Nietzsche
In the context of a new edition dealing with the literary heritage of Friedrich Nietzsche, his work and notebooks were published in a differentiated transcription. That means that only those additional notes and amendments ascribed to Nietzsche were represented in the new publication, whereas the others were simply annotated descriptively. Regarding the complex variety of differentcoloured corrections such as crosses, lines, etc. in the texts, it is visually not possible to distinguish between different authors. In order to differentiate coloured notes, the chemical composition of several coloured crayons used in the manuscripts was investigated by XRF analysis (Figure 8). On the basis of different inorganic admixtures, the crayons should be characterized by means of qualitative and quantitative fingerprints.
For a pilot study, the investigations were carried out in three different notebooks. The results for the red crayons are presented in Figure 9. Even without a quantitative evaluation it is possible to distinguish precisely between four different types of red crayons (red 1 - red 4). It is worth mentioning that each crayon was used in more than one notebook. The qualitative fingerprint results in a characterization which is much more accurate than using visible spectrophotometry [23]. For a first semi-quantitative interpretation, without consideration of the paper background, the group 'red
2', containing mercury (Hg) and lead (Pb) in noticeable quantities, is of special interest. The measurements reveal that the ratio of Hg to Pb is constant, so it may be concluded that the same

type of crayon was always used. These first measurements on coloured crayons in Nietzsche's notebooks reveal that it is possible to distin-
Figure 8 Friedrich Nietzsche, notebook with coloured marks.
Figure 9 XRF spectra of four different types of red crayons. Each crayon was used in more than one notebook. guish between different notes written by Nietzsche and by his successors. Because of the multitude of diverse markings, further measurements are necessary for a comprehensive interpretation.

XRF analysis of two pencils used by Johann Wolfgang von Goethe
In view of the qualitative XRF analysis of iron gall inks and coloured crayons respectively, as well as the application of the fingerprint method to these materials, it has to be asked if it is possible to distinguish between different pencils based on their chemical composition. As described before, pencils usually consist of the main component carbon, which is not detectable by XRF. The second main component contains iron (Fe), aluminium (Al), silicon (Si) and sodium (Na), but these elements do not seem to be significant to distinguish between different pencils. So the analyses focus on minor components or trace elements to attain distinctive characterizations.
In a pilot study, two different pencils, again used by Johann Wolfgang von Goethe, were investigated. The first one was analysed in a manuscript and showed no
Figure 10 Representative XRF spectra of two different pencils used by Goethe. The first one was analysed in a manuscript originating before 1800. The second one belongs to a retractable pencil originating from the early nineteenth century. characteristic elements (see the dashed line in Figure 10). XRF analysis of the paper showed that the iron comes for the most part from the paper itself. However, investigation of a retractable pencil from the early nineteenth century reveals a distinct amount of chrome compared to other admixtures. Again, this element indicates an application occurring not before the nineteenth century. Based on these results it could be possible to distinguish between Goethe's sketches completed before and after 1800. Further measurements concerning other admixtures will allow a more precise distinction.
CONCLUSIONS
In this paper the authors employed a micro-XRF method for the investigation of different writing materials. It is the first time that pencils and coloured crayons have been investigated in this way.
The method takes into account both the heterogeneity and the layered structure of historical samples. As shown in this paper, it can provide essential contributions to historical and archaeometric research without taking any samples.
In the case of iron gall inks the qualitative and quantitative investigations of the inorganic compounds lead to exact characterizations of the different inks, summarized by means of

fingerprints. These composition fingerprints allow us to distinguish between various inks and therefore to establish a chronology of ink types used by one artist, as well as to study the genesis of manuscripts by separating later corrections and amendments from the original sketch. Finally, this method might permit distinction between an original and a falsification. Further measurements on coloured crayons and pencils demonstrate that it is possible to use the fingerprint model on other writing and colouring materials to cany out chronological classifications.
ACKNOWLEDGEMENTS
The authors thank Dr Jochen Golz, Elke Richter, Marie-Luise Haase, Nicole Stiebel and Karin
Ellermann. Goethe- und Schiller-Archiv, Weimar. Special thanks to Dr Katherine Roegner (Berlin), for her valuable suggestions in correcting drafts of this paper. We are also grateful to Ulrich
Waldsehlager (Rontec GmbH, Berlin) for his versatile support.
MANUFACTURERS AND SUPPLIERS
Portable X-ray fluorescence spectrometer: Rontec GmbH, Schwar/schildstr. 12. 12489 Berlin,
Germany.
REFERENCES
1 Lah.inier. Ch.. Anisel, G., Heitz, Ch.. Menu, M., and Andersen. H.H.. 'Ion beam Analysis in the arts and archaeology", Nuclear Instruments and Methods in Physics Research B 14 (1986) 1—5.
2 Pirolo. P., Truixi, I., Del Carmine, P.. Lucarelli, F., Mando, P.A., Galluzzi, P.. Damerow, P.,
Renn.J., and Rieger, S., Pilot
Study for a Systematic PIKE Analysis of the Ink Types in Galileo's Ms. 72, Project Report No. 1,
Preprint 54, Max-Planck-lnstittit fur Wissenschaftsgeschichte. Berlin (1996).
3 Mantler, M., and Schreiner, M., 'X—ray fluorescence spectrometry in art and archaeology",
X-Ray Specirometry 29 (1) (201)0) 3-17.
4 Janssens, K.. Vittiglio, G., Dereadt. I., Aerts. A., Vekemans, B., Vincze, L., Wei, F.. Deryck, I.,
Schalm, O., Adams, F., Rindby, A.. KnScliel, A., Simionovici. A., and Snigirev, A.. 'Use of microscopic XRF for non-destructive analysis in art and arche.omer.ry'. X-Ray Spcctromeiiy 29 (1)
(20(10) 73-91.
5 Muspratt, H.. llucyclopiidisches Handhuch der technisclien Chetnie, Vol. 8, Braunschweig,
Vieweg (191)5) 1278.
6 KSnig, R-. and Winkler, G.. Gains Pliniits Seciiiidns. nannalis historia, XXXIW Miinchen (1978)
I 12.
7 Konig, R.. and Winkler. G.. Gains Plinius Secnndns. naumdis historia, XXXI'. Miinchen (197S)
184.
8 Fuchs, R.. H.ihn, O.. .md Oltrogge. D., 'Geisr und Seele smd verwirret...l)ic TintcnfraB —
Problematik der Bach-Autographe". Restanm 2 (2000) 116-121.
9 Hickel, E.. Ghemikalieu im Ar~neischat: deutscher Apoiheken des 16. Jahrhunderts nnter besouderer Beriicksichtioung der Metalle. PhO thesis, University ot Brunswick (1963).
10 Kraschewski, H.-J.. "Vitriole aus dem Rammclsbcrg' in Der Ramntclsberg. TansendJidirc
Mensch
—
Natur
—
Technik. Ber^lum als Knllnrlriigcr (Band 2). ed. R. Roseneck. Verlag
Goslarschc Zeitung Karl Krause, Goslar (2001) 344-356.
11 Koschatzky. W.. Die Knnst der Zeicltnuno
— Technik. Geschichte, Meisterwcrkc, 8. Aufl.
DTV-Verlag, Miinchen (1996) 46.
12 Ullmann, F., Enzyhlojhidic der Technisclien C.hcmic, Vol. 8. 4th revised edition, Berlin.
Wemheim (1972-1984) 600-604.

1.3 Hahn, O., and Gorny. H.E.. 'Zerstorungsfreie Charakterisier-ung historischer Eisengallustinten mittels Roiitgenfluores-zenzanalyse', Zeitschrift lur Kunsttechuolo^ie mid Konsciviennitf 14 (2000)
384-390.
14 Hahn, O., Maker. W.. Kanngiel'.cr, B., and Beckhoff, B.. 'Characterization of iron gall inks in historical manuscripts and music compositions using X-ray fluorescence spectrometry', X-Ray
Spectrometry 33 (2oo4) 234-239.
15 Hoffmann, K., Bichlmeier, S.. Heck. M.. Theune, C. and Callmer. J.. 'Chemical composition of glass beads of the Merovingian period from graveyards m the Black Forest, Germany", X-Ray
Spectrometry 29 (2000) 92-100.
16 Werner, A.E.. Bimson. M.. and Meeks, N.I).. 'Use of'replica techniques and scanning electron microscopy in the study of ancient glass'. Journal of Glass Studies 17 (1975) 158-160.
17 Rye, O.S., 'Amgama — the art of uncertainty". Ceramics, An and Perception 10 (1993) 39-42.
18 Malzer, W.. Hahn, O., and KanngieBer, B., 'A fingerprint model for inhomogeneneous ink paper layer systems investigated with micro X-ray fluorescence analysis', X-Ray Specirometry 33
(2004) 229-233.
19 Arkadiev, V.A., Bjeoumikhov, A.A.. Gorny, H.E., Schiekel, M., and Wedell, R., 'Use of polycapillary structures for X-ray fluorescence analysis'. Journal of Trace and Microprohc
Techniques 14 (1) (1996) 131-135.
20 Hronk, H., Rohrs. S.. Bjeoumikhov, A., Langhoft", N., Sehmalz. J.. Wedell. R.. Gorny,
H.E.. Herold, A., and Waldsehlager, U., 'ArtTAX": .1 new mobile spectrometer for energy dispersive micro X-ray fluorescence spectrometry on art and archaeological objects', l-reseuius
}ourtnil of Analytical Cliemistry 371 (2001) 307-316.
21 Krekel. Ch., 'Chemische Struktur historischer Eisengallustinten'. Werkhefte der Staatlichen
Archivvcrwaltung Badeu-Wiirtetnbeix, Serie A, Landesarchinlirektion 10 (1998) 25-36.
22 Kanngiel'.er. I!.. Hahn, O., Wilke. M., Nekat, B., Malzer, W. and Erko, A., 'Investigation of oxidation and migration processes in ink corroded manuscripts', Spectrochimica Acta B 59/10-11
(2004) 1511-1516.
23 Colli, G., Montinari, M.. Miiller—Lauter, W., Pestalozzi. K., and Haase, M.—L., (eds.).
Friedrich Nietzsche H'erke, Kritische Gesamtausgabc, Abt. 9. Bd. 1-3, Xotizhefl N I'll I; Notizheft
N 1 11 2: Notizhefte i\" 1 11 3. .V I II 4 (2001).
AUTHORS
O
LIV
E
R
H
AHN received his PhD in chemistry and art history in 1996. After employment as research associate m the Department tor Restoration and Conservation of Books, Graphic Arts and Archival
Materials at the University ot Applied Sciences in Cologne, he is currently working at the Federal
Institute tor Materials Research and Testing in Berlin. Address: Federal Institute for Materials
Research and Testing, Lab. I]'.22, Unter den Eichen 44—46, 12203 Berlin, Germany. Entail: oliver.hahn @bant.dc
B
IR
G
IT
KANNGIEßER received her PhD in physics in 1995. After employment as research associate at the University in Bremen, she was granted scholarships sponsored by the Deutsche
Forschungsgemeinschaft (DFG). She is currently working at the Technical University of Berlin,
Institute for Atomic Physics and Teacher Training. Address: 'Technical University of Berlin,
Institute for Atomic Physics and Teacher Traininc;, Harden-bcrgstr. 36, 10623 Berlin, Germany.
Email: bk@atom. physik.tu-berhn.de
W OLFGANG M ALZER graduated in physical technics in 1988. He is currently working as research associate and doing his doctorate at the Technical University of Berlin, Institute for Atomic Physics and Teacher Training. Address as for Kaunc;ie(lcr. Entail: u>olf@atom. physik.tu-berlin.de

Résumé —
L'investigation quantitative ci qualitative de documents historiques au moyen de la
mkrqfluorescence X (micro-XRF) est une méthode fiable pour obtenir la composition précise (« empreinte digitale ») de différentes encres et crayons de couleur. L'analyse quantitative est basée sur un modèle prenant en compte l'hétérogénéité et la structure des couches des échantillons historiques. Fin partant de ces comparaisons il' « empreintes digitales », il est possible de faire la différence entre diverses encres
fenogalliques utilisées par un artiste pour établir une chronologie de leur usage et, par la suite, pour dater les fragments inconnus qui n'auraient pas pu être intégrés jusqu'ici dans l'œuvre de cet artiste. Les analyses qualitatives et quantitatives de plusieurs manuscrits de Johann Wolfgang von
Goethe clarifient la chronologie de leur genèse. Les investigations sur le manuscrit d'Achim von
Arnim 'Studien zu Naturwissenschaften' montrent que divers mécanismes de dégradation de l'encre fcrrogallique pouvaient également être reliés à différentes compositions inorganiques. Des mesures faites sur des crayons de couleur dans les carnets de notes de Friedrich Nietzsche ont montré qu 'il est possible de distinguer entre les notes écrites par Nietzsche et celles écrites par ses successeurs.
Finalement, les analyses de deux crayons différents de Goethe montrent qu'il peut être possible de faire la distinction entre ses croquis exécutés avant et après 1800.
Zusammenfassung
—
Die qualitative und quantitative Untersuchung historischer
Schreibmaterialien mit Hilfe der Mirkroröntgcnfluoreszenzanalysc (Mikro-RFA) ist eine geeignete
Methode, anhand derer „fingerprints" der Zusammensetzung verschiedener Tinten und Buntstifte erhalten werden können. Dabei basiert die quantitative Analyse auf einem Modell, daß die
Heterogenität und die Schichtenstruktur ¡1er historischen Proben in Betracht zieht. Ausgehend von der Zusammensetzung der "ßngcrpnuts" ist es möglich, zwischen verschiedenen
Eisengallustinten zu unterscheiden und so eine Chronologie der Verwendung durch einen Künstler
zu entwickeln.. Damit können unbekannte Fragmente, die bisher nicht in das Oeuvre eines
Künstlers integriert werden konnten, datiert werden. Die qualitative und quantitative Analyse einiger Manuskripte von Johann Wolfgang von Goethe erlaubte es, die Chronologie deren
Entstehung zu klären. Die Untersuchung des Manuskriptes 'Studien zu Naturwissenschaften' von
Achim von Arnim zeigte verschiedene Abbaumechanismen durch die Eisengallustinte, die jeweils mit unterschiedlichen Zusammensetzungen der Tinte korreliert werden konnten. Messungen an den
Farbstiften in Nietzsches Notizbüchern zeigten, daß es möglich ist, zwischen seinen eigenen
Notizen und denen seiner Nachfolger zu unterscheiden. Nicht zuletzt war es durcit die Analyse
zweier von Goethe verwendeter Stifte möglich, zwischen Entwürfen zu unterscheiden, die vor und nach 1800 entstanden sind.
Resumen — La investigación cualitativa y cuantitativa de materiales históricos de escritura usando micro fluorescencia de rayos X (micro-XRF) es un método apropiado para obtener composiciones típicas de las diferentes tintas y tizas o barras de color. El análisis cuantitativo se basa en un modelo que toma en cuenta la heterogeneidad y estructura en las capas de las muestras históricas.
Comenzando a partir de estas 'composiciones tipo' es posible distinguir entre las diferentes tintas ferro gálicas usadas por cada individuo para establecer cronologías de uso y, lo que es más, datar fragmentos desconocidos que no pueden de otra manera ser integrados en la obra de un artista.
Los análisis cualitativos y cuantitativos de diversos manuscritos de Johann I ( olfgang von Goethe clarifican las cronologías de su génesis. La investigación del manuscrito de Achim von Arnim
'Studien zu Naturwissenschaften' indica que los diversos mecanismos de degradación de las tintas ferro gálicas pueden ser relacionados con su diversa composición inorgánica. Mediciones adicionales realizadas a las tizas coloreadas empleadas en los cuadernos de notas de Friederich
Nietzsche revelan que es posible distinguir entre las notas realizadas por el propio Nietzsche y las de sus seguidores. Finalmente, los análisis de dos diferentes lápices de Goethe revelan que podría ser posible distinguir entre sus esbozos realizados antes y después de 1800.