III.5 Drawing and Photography
p. 71-77
Texte intégral
1Technical drawings and photography provide selected attributes of pottery useful for comparison and sharing among the scientific community. Technical drawings act as a reconstructed visualisation of an object, most often beginning with a single sherd, which allows to present manufacturing techniques, dimensions, surface treatments or decorations in combination with a reconstructed comparable shape.
2Photography forms a second layer of information expressing the present state of the object. Both techniques respect certain standards to which academics are subject, even though the method and specifics thereof can vary from one person to another according to their experience and to the publication specifications (for more details see Olin, Dillon 1987; Griffiths et al. 1990; Aston 1998, pp. 13-25; Banning 2000, pp. 282- 287; Collett 2012).
Technical Drawing
3Technical drawing of sherds is a matter of experience and practice. What can take half an hour or more at the beginning can be achieved in much less with a little practice. It is important to understand that technical drawing follows defined rules and has nothing in common with artistic drawing (see Section iv.1). The most important aspect is the accuracy of the drawing which reproduces the external characteristics of the sherd to be drawn precisely. The purpose of technical drawings is to illustrate the profile of the sherd—a view of its vertical cross-section, that is as if we were looking through it from the outside—and therefore to produce a comparable and shareable dataset (fig. 31). However, it should be noted that there are several ways of proceeding with the technical drawing of a pottery vessel. The faithful result is what counts, and any helpful tools are welcome.
Figure 31. From a ceramic to its technical drawing

Adapted from Banning 2000, fig. 16.8.
Equipment for Drawing
4The minimum set of equipment required by the technical draughtsman includes: Tracing paper, Graph paper, sharpened pencils or technical pens (0.5 to 0.3 mm with hard leads 2H to 4H), a rubber, one or two set squares with measurements beginning at the edge, vernier callipers, a diameter/rim chart and most importantly a profile gauge (comb). The latter is more expensive and sometimes difficult to find. The 15 cm metallic profile gauge with fine metallic teeth is preferable to replicate the profile (vertical section) of the pots with precision but it should be used with great caution on fragile or painted pottery.
Drawing Sherds with a Profile Gauge
5The first step of a drawing is to obtain the external vertical profile of the sherd (fig. 32). It can be easily taken with a profile gauge by holding it in one hand and applying it vertically to the sherd. A small wooden stick or your finger can be used to gently push the small metallic teeth of the profile gauge so that they follow any subtle changes on the external vertical section of the sherd (fig. 33 a). Then the profile gauge is placed flat down onto the tracing paper and, with the aid of a pen, the obtained profile can be drawn (fig. 33 b).
Figure 32. The various parts of a vessel

6The second step is to measure the thickness of the sherd with the calliper tool (fig. 33 c) at various points: at least one at the top edge, one at the bottom edge and one in the middle in the case of a simple shape and as many points as required in the case of a complex one with more extensive variability of thickness within the section.
7The measurements must be transferred onto the drawing with precision; it is recommended to use small dots drawn with the pen or by creating little marks with the sharp points of the callipers (fig. 33 d).
8The inner profile can now be obtained following the same procedure as for the external one. It can be drawn on a separate sheet of tracing paper as a draft and then copied in cleaner lines onto the final sheet after being aligned with the measured thickness landmarks or it can be directly included in the same drawing as the external profile. This last option entails supplementary manipulation of both the profile gauge and the tracing paper.
Drawing Sherds or Complete Pots without a Profile Gauge
9In the case of a complete pot or in the absence of a profile gauge, the drawing can be achieved with a triangle and a ruler only. First, the object must be correctly positioned (on its rim edge) against the triangle (figs. 33 e and 34). Once in the right position, measurements of each major point or each centimetre if the shape is quite regular can be taken. The calliper is used to draw the internal profile in the case of a sherd. For a complete pot, another ruler placed on the rim serves as the basis to define the lowest point of the inner profile (fig. 33 h). Without a profile gauge, the skill, measurement accuracy and the eyes of the draughtsman are put to more demand.
Figure 33. The different steps of the technical drawing

Orientation
10The orientation of the sherd is the next key element as it allows, when done correctly, to define the type of vessel (open or closed) and its group of reference (plate, bowl, etc.). Generally within a technical drawing, we are assuming that the rim is circular and that the pots have been placed upside-down whilst drying. In this latter process the whole diameter (horizontal of the rim area) is in contact with the ground, floor or a flat surface on which the pot has been left (fig. 34). This contact point of the vessel with a flat surface line forms what is called the orientation line (fig. 33 e). Consequently, no light is visible between the rim of a sherd and the flat surface if the rim is correctly oriented. The orientation should be checked several times in case of uncertainty.
Figure 34. The technical drawing with a triangle

11To record the measurements for the orientation, the actual orientated sherd is placed against a triangle and measures of its height and of the distance between some identified points (rim edge or bottom edge) and the triangle can be taken and transferred onto the drawing (as described for the thickness measurements). With all these collected measurements, the pre-prepared but still non-orientated section drawing acts as a one to one and the orientation line can then be established.
Determination of the Diameter
12In the following step the diameter will be determined. For this, a rim sherd is placed with the rim edge (again up-side down) orientated (as before for the determination of the orientation on the “flat surface”) on a so-called rim or radius chart (fig. 33 f). With the use of a rim chart a vessel’s rim or base radius or diameter, as well as their preserved proportions can be determined.
13The diameter or radius information will be added to the drawing where the orientation line acts as the virtual diameter. Now the external section can be mirrored to the other site and factually displays the so-called “reconstruction part” of the technical drawing (fig. 33 g).
Internal Lines and Shadow
14The internal lines reflect the vertical changes of the section and highlight the details that the draughtsman finds relevant for the illustration of the sherd. They provide the viewer with a sort of 3D effect and allow for easier comparison. Further pencil illustrations also act as representations of certain surface treatments and decorative elements etc.
Advice
15Careful verification should be carried out to ensure that all individual drawings include their ID number written clearly as well as the name of the draughtsman. Care must also be taken in numbering each drawing sheet and preparing a list of which objects are drawn on which sheet; this will make the later process of digitisation and publication easier.
File Format and Archiving
16The scan of the drawing sheets must be done thoroughly, as it forms the base for the catalogue and presents the actual framework of the pottery (or finds) analyses. It is advised to scan using 600dpi Tiff in greyscale. This permits an optimal “one to one” digital picture without any loss of pixels, maintaining measurements, and should be archived as such.
The Photography of Ceramics
17The ceramic specialist is rarely a professional photographer even if some of his pictures are usually published in academic papers. In this section, some recommendations are given to take suitable photographs without entering into the considerations a professional would take into account with his specific material. These aspects are developed in other dedicated manuals (See e.g. Dorrell 1994; Foster, Barker 1996; Riviera 2014; Verhoeven 2016).
Equipment for Photographing
18The minimum set required to take suitable photographs for publication would include: various scales of different shapes (5 cm, 10 cm, flat and right angle ones), an obligatorily matt background whether it be white, black, grey or even blue, a camera and, if possible, a tripod.
Setting up a Photo Lab
19A photo lab can be installed wherever suitable as long as the light conditions can be controlled. Natural sunlight usually gives good results but only during a few hours per day depending on the spot chosen (close to a window for example). Artificial lamps can be used at all times but require electricity or regular charging. Ideally, the camera is installed on a tripod to avoid any movement while shooting.
20Two light sources are placed at a 45-degree angle on each side and close enough to the object to minimise shading. In the absence of a lamp, a reflector (or a white paper) can be used to reflect the sunlight on the opposite side of the light source. The main source must always come from the top left-hand edge (as for technical drawings): this practice makes it possible to juxtapose images on a plate without the eye confusing the grooves and the ridges (fig. 35).
21A clean background is placed on the flat surface and equally behind the object in the case of horizontal view. A dark background can be favoured in the case of light-coloured/pale objects.
22The scale, adapted to the size of the object, is placed close to it, just below the object in the case of photographs from above or to the side when pictured horizontally.
Figures 35. A “photolab” installed at the Sfdas; 36. Example of ceramic viewed from profile

23The photographs must not be too dark or overexposed. The automatic mode on recent cameras is generally good enough to optimize the photographs.
What Kind of Shot for What Kind of Ceramics
24The photographer defines the view, details, quality, and quantity of pictures he wants to record so as to correctly adapt the adjustments and the position of the camera.
25Ceramics, either complete or broken, must be pictured in correctly orientated with their opening on top (fig. 37). Equal space should be left on each side above and beneath the composition (object with scale).
Figure 37. Examples of a ceramic sherd

26The complete record of a ceramic requires various views. It is important to take several photographs of the same object from different angles to enable understanding of the object as a whole. The angle of view must be adapted to the type of object. Sherds can be shot flat (camera above) while complete ceramics can be pictured from a lower angle to show their profile (fig. 36). Also, additional pictures of decorative details or fabrics should be considered.
File Format and Archiving
27The JPEG format is the most commonly used nevertheless TIFF or RAW offer much better quality and enable for later light/colour and size manipulation without any loss of pixels. As for the drawings, each photograph should be labelled immediately after the session according to the labelling set up for the mission.
Diameter chart

Persistent identifier: https://doi.org/10.34847/nkl.e4afk17d.
Download (pdf/332 kb): https://api.nakala.fr/data/10.34847/nkl.e4afk17d/0c68d0dc6f94ed3ed2bcbed0fdd9fe729712e464.
Auteurs
Associated member, Deutsches Archäologisches Institut, Berlin, Germany.
Researcher, Section française de la direction des Antiquités du Soudan, Khartoum, Sudan.

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