The physical arrangement of space and facilities in an archaeological laboratory is important to the efficient use of staff and resources. Although academic and private-sector archaeological laboratories differ in some respects, such as the need for teaching space in some of the former, they have many needs in common.
General Space and Furnishings
A general archaeological lab, in both academic and CRM settings, needs to be spacious enough and have adequate facilities to accommodate a large variety of archaeological analyses and curatorial needs. In general, the lab needs to be dry, clean, and secure, with moderate and stable temperature and humidity. Storage and work areas should be away from major traffic but easily accessible by lab carts. The layout of the lab should be amenable to the work flow, minimizing the chance that lab carts or personnel will interfere with one another. Work areas should be well lit yet avoid excess direct sunlight, while storage areas should usually be dark or have low-UV lighting. Work and storage areas, and individual cabinets, should be lockable and only authorized lab personnel should have access to keys or combinations.
The most critical furnishings for a general archaeological lab are tables or lab benches for working space and shelving, cabinets, or both, for both temporary and long-term storage.
Many archaeological labs have benches identical to those used in chemistry or biology labs, with a smooth, washable work surface at a height that is suitable for working while standing (37-38 in), while seated on a stool (38-40 in), or while seated at a computer keyboard (c. 28 in). Cabinets and drawers beneath the work surface provide space for storage of small equipment and supplies, and sometimes also for the temporary storage of artifacts or other samples that are in the processing or analytical queue. To accommodate the legs of seated workers, the cabinetry needs kick spaces at intervals, while the fact that the benches are permanently fixed in place makes them unresponsive to changing spatial requirements.
Other labs have tables in lieu of, or in addition to, lab benches. Tables have two principal advantages: they provide more leg room for seated workers, and one can move the tables around as needs change. However, they also have the disadvantage of lacking space to store items out of the way, except to stack boxes on the floor underneath. Consequently, many archaeological labs employ mixtures of benches and tables, of varying heights.
Both benches and tables should be deep enough to accommodate the trays or removable drawers used in the laboratory storage cabinets without hanging over the table edge. Otherwise there is risk of bumping into a tray and upsetting the artifacts or other specimens on it. Since bench and table tops are hard, they should be equipped with padded sheets, such as thin sheets of polyethylene foam, both to protect their surfaces and especially to guard against breakage of fragile artifacts dropped on surfaces.
Where cleaning very dirty artifacts is a substantial laboratory activity, some labs employ specially built tables or racks with heavy mesh in place of the table top. This allows loose dirt to fall through into a basin below during artifact cleaning, or facilitates drying of artifacts after washing. In some cases, compartmen-talization of such mesh tables or racks by adding a raised grid of wood or metal both strengthens it and allows easy sorting of artifacts or prevents the mixing of artifacts from different bags or contexts.
Since archaeological analysis is often timeconsuming and the quantities of material to analyze are often very large, the laboratory needs to be able to accommodate at least temporary storage of material waiting for, or in the process of, analysis. Storage systems should organize specimens in a way that facilitates their location, retrieval, and return; minimizes physical jostling and friction; discourages theft or unauthorized access; facilitates monitoring of contents and their condition; and maintains a stable, safe environment.
One excellent means of accomplishing this is by equipping the lab with secure cabinets with numerous shallow trays. Particularly when the materials needing storage are sensitive to fluctuations in humidity and temperature, and also to minimize dust levels in the lab, the cabinets and drawers should ideally be of metal, with lockable doors that close and seal tightly. The contents of such metal cabinets will thus be somewhat isolated from the laboratory’s airspace. Wooden cabinets or shelving may be acceptable in some circumstances - for example, storage of chert and other very stable artifacts - where conservation issues are forgiving, but the acidic fumes that some wood and glues will slowly exude are particularly damaging to metal artifacts. Putting any wooden shelving in a well-ventilated area, rather than keeping it airtight as in the metal cabinets, will help prevent fumes from accumulating.
Other things to consider in planning shelving or cabinetry for storage of artifacts pertain to both conservation and practicality. Repeated sliding of drawers or trays in and out shifts specimens so that friction and rattling can damage fragile artifacts and bone fragments. Lining the drawers or trays with a membrane made of an inert material, such as polyethylene foam, will help reduce this friction effect. Meanwhile, drawers or trays should be sturdy, easily removable, reasonably light (particularly given the weight of the specimens they will carry), and not unduly large. It is helpful if the cabinets allow very flexible spacing of the trays or drawers, to accommodate both small and large specimens. Each tray or drawer should have drawer pulls, to facilitate withdrawal while also helping to orient the drawer on its return from a bench top. Trays or drawers should also have slots on front to hold labels that indicate their contents.
In general, the storage system should make sense archaeologically and conservationally. Often, this means organizing collections in a way that separates specimens that we need to access frequently from ones in long-term (‘dead’) storage, and often it also means separating specimens by their various environmental needs. For example, very unstable materials, such as iron, need close environmental control and monitoring in sealed containers, while less sensitive materials have less restrictive but still real requirements.
Each laboratory should have a wheeled table, lab trolley, or cart with which to move trays and boxes of artifacts. In order to minimize the chance of dropping and damaging artifacts, lab staff should always use this cart rather than carrying large or multiple artifacts by hand. For moving heavier boxes, it is also a good idea to have a decent dolly or hand-cart with good tires.
Generally, the laboratory will need at least one large bookshelf unit to keep field notes, photo logs, slides, and other hard-copy documentation, as well as laboratory manuals and reference books.
Stools and chairs are also essential furnishings. Given the long hours that some staff will spend seated, it is essential to take proper ergonomics into consideration. Make sure that the chairs’ heights are adjustable to make work comfortable at the particular tables or benches in the lab. Good lighting is also an essential aspect of laboratory furnishings, particularly considering the close and detailed work that lab staff must carry out. Typical fluorescent lighting is not very satisfactory, unless supplemented with many table lamps and with natural light from large windows. It is important to position the work spaces for particularly eye-straining work, such as drafting or lithic recording, close to such windows, both to ensure adequate light and to allow those carrying out the work to look out of the window periodically. Changing the focus of ones’ eyes from time to time in this way reduces eyestrain. Small, goose-neck table lamps with halogen bulbs make it easy to direct light onto small objects and to cast shadows that make it easier to observe small details of relief.
Most archaeological laboratories also need at least one deep sink and faucet, which is useful for washing artifacts, washing up some of the tools, beakers, and pens used in the lab, and for lab staff to wash their hands. If artifact washing or sediment processing is among the lab activities, it is important for the sink’s drain to be equipped with a silt trap. Most often, the sink will be set into a cabinet to allow storage of basins and the like below. It is also good to have some wall shelving above the sink.
Many archaeological laboratories also need some kind of refrigeration. Zooarchaeology labs that carry out skeletal preparation, for example, will either need several large deep-freezes or a walk-in freezer to store animal carcasses prior to their preparation. Others will instead need a cool-room or small refrigerator to store film, some kinds of specimens that would degrade faster at room temperature, or even archival photographs.
Even though archaeological projects have been moving increasingly toward digital imagery, it is still almost essential for an archaeological lab to have at least one steel map cabinet. This serves to store oversized maps and drawings flat, which is generally preferable to the alternative of keeping rolled-up maps and illustrations in plastic tubes. Archaeological labs also sometimes have a drafting table (often still used at least to prepare preliminary drawings of artifacts for later digitizing) or a light table (useful for sorting slides and transparencies, as well as for object photography and tracing maps and drawings).
Since most of today’s archaeological labs are thoroughly computerized, it is necessary to ensure that some of the cabinets or, alternatively, dedicated computer workstations are set up for data entry and analysis. These should be positioned in such a way as to minimize glare on the monitor, have chairs and keyboard surface set at ergonomically appropriate heights, and ideally have high-speed Internet access and their own, surge-protected electrical circuits or uninterruptible power supply. Where there are several computers, it is good to set up a local area network with a shared laser printer and scanner accessible to all users.
Some archaeological laboratories, especially those that employ hazardous chemicals, require at least one fume hood and an explosion-proof chemical-storage cabinet.
Small Equipment
Specialized archaeological laboratories have their own needs, but most archaeological labs require a number of basic tools and instruments. These include electronic balances with a variety of capabilities in terms of the maximum mass they can measure and the precision of measurement (e. g., up to 6 kg to nearest 2 g or up to 500 g to nearest 0.1 g). The lab should have standard brass weights with which to calibrate the balances. They also include several inexpensive manual calipers and usually at least one electronic caliper, preferably able to interface with a computer for automatic uploading of measurements. The ‘jaws’ of the calipers, if made of steel, could damage the surfaces of fragile artifacts, so plastic ones are preferable. Putting masking tape on the jaws to cushion the hard metal is unacceptable because of the bias it causes, except in the case of electronic calipers that one can re-zero. Other small tools include dental picks and tweezers for fine work. Most archaeological laboratories also need at least one low-power binocular microscope and a number of hand lenses, such as jewellers’ loops. Table lamps, including swing-arm lamps with magnifiers built-in, and a fiber-optic light source for each microscope are essential, even where there is fairly good natural light. A tripod and copy stand with a pair of strong lamps is very useful for object photography. Some labs will have a power drill, Dremel tool, or geological saw for removing samples from artifacts or bones for chemical analysis or thin sections. Munsell soil-color charts, standard mineral sets for determining hardness, and pH meters are also common items of small equipment in archaeological labs. Routinely, the lab will have at least one desktop computer, flatbed scanner, printer, backup (removable hard drive, CDs, flashcards), and fast Internet connection.
Laboratory Supplies
The most common archaeological laboratories require a variety of basic supplies for the storage, cleaning, recording, and maintenance of collections, and safety of lab personnel (Table 1 ).
Temporary storage, unpacking, and sorting When artifacts and other archaeological samples arrive at a lab, a first step is to move them into a space where lab workers can unpack them, do preliminary sorting, and carry out a kind of ‘triage’: deciding which items need immediate attention and which can be moved into longer-term storage.
These activities require something like a staging area near the lab entrance, tables or lab benches where staff can open boxes, sort artifacts, and arrange them on trays. Either spacious and sturdy shelves or cupboards under the benches are essential for temporary storage and to help sort unopened boxes.
Note that it is important, at this stage and throughout the analysis process, to minimize the chance of breaking or damaging artifacts as they are moved, sorted, or handled. Consequently, staff should always use a lab cart, rather than just their hands or arms, to move trays and artifacts from one part of the lab to another.
Basic processing Apart from samples that can safely wait in longer-term storage, most materials that arrive at the lab require fairly immediate attention by way of sorting, cleaning, and labeling.
Measurement Diameter charts for pottery
Measuring charts for lithics
Recording forms pH litmus paper Calibrating tablets for pH meter
Office and Drafting
Printer paper
Printer toner
Writable CDs or DVDs
Writing pads
Clear tape, masking tape
Staples
Pens, pencils, technical pencils Erasers
Drafting vellum or mylar film
File cards Manilla envelopes Rubber stamps and ink pads
Table 1 Basic supplies commonly needed in an archaeological laboratory
Health and safety First-aid kit (esp. bandages)
Dust masks
Goggles or face shields Spill kits
OSHA or WHMIS manual, material safety sheets, hazard labels Latex gloves (several boxes)
Work gloves
Lab coats and/or aprons
Collections management Polyethylene bags, various sizes Silica gel
Humidity indicator strips Plastic boxes with see-through lids Polyethylene foam sheets Pens with stable ink Artists’ paint brushes Acryloid B72 and Acetone Stick-on labels
Printed labels for cabinet drawers
Staples
Binders
Archival photo pages Small brushes for cleaning artifacts Acetic acid for removing CaCOs Distilled water
Cleaning and labeling are critical in an archaeological lab. Archaeologists are well aware of the importance of archaeological context; consequently, any sorting that might separate an artifact from its original bag or label would be disastrous unless an accurate label accompanied it. In addition, while cleaning and labeling, staff will pay close attention to any adverse preservation issues associated with samples, so that they can send them for conservation before they proceed to analysis.
Ideally, the ethics of artifact conservation call for us to alter artifacts only in ways that are reversible. At the same time, the priority on preservation of contextual information calls for us to ensure that any labeling we use is reasonably secure and permanent. We do not want labels that are easily separated from the artifact or likely to wear off. In order to balance these competing demands, a good practice is to apply a strong yet reversible base layer to a clean, dry surface on each artifact, apply a label on top of this surface, and then seal the label with another transparent layer. Traditionally, archaeologists used India ink and a crow-quill pen to apply the labels, but today they tend to favor fine-point commercial pens, whose ink composition is often unknown because of patent protections. A commonly used material for the base and cover layers is 10% acryloid (paraloid) B72 in acetone, which is soluble in acetone and therefore easy to remove. The main drawback to its use, especially for the top coat, is that most of the commercially available inks that archaeologists use to write labels on the base coat are also soluble in acetone, so that the labels tend to smear or get erased when we apply the top coat of B72. If we are unable to use suitable inks that are stable in acetone (India ink is one), possible solutions to this problem are to adhere small, printed paper labels to the bottom layer of B72 and seal them with the top coat, or to use a transparent top-coat that is soluble in mineral spirits instead of acetone.
One of the reasons for cleaning at least a portion of the surfaces of artifacts is to ensure strong cohesion of the label. Cleaning is also necessary to allow some kinds of analysis, while, at the same time, there are also many circumstances in which analysis demands uncleaned and uncontaminated surfaces. During the ‘triage’ stage, lab personnel must separate out any items for which cleaning would not be appropriate, including ones that cleaning might damage, and ensure that each gets its own labeled polyethylene bag. A labeled bag is not as secure a labeling medium, since there is always the risk that the artifact and bag could be separated, or different artifacts get mixed up, but careful use of labeled bags is often our only reasonable alternative to direct labeling of artifacts and other samples. Furthermore, it is important to avoid condensation inside the bag. Where this is a possibility, pierce the bag with small pinholes to allow excess moisture to escape.
Basic conservation and cleaning As mentioned above, it is not appropriate for all artifacts and samples to undergo cleaning. One of the most common reasons to avoid cleaning is to avoid contamination that would undermine chemical or isotopic analysis, including radiocarbon dating and analysis of chemical residues on lithics or in pottery fabrics. Another is to preserve microscopic traces for use-wear analysis. In addition, cleaning, especially cleaning that involves immersion in water or ultrasound, could damage or even destroy fragile specimens, and some artifacts, such as metal ones, should only be cleaned by trained conservators.
Most artifacts, however, can withstand careful, gentle brushing to remove loose dirt, and many artifacts can withstand immersion in water and cleaning by gentle brushing. Lab personnel should avoid vigorous brushing, as it can erode artifact surfaces or even cause breakage. If they use water-washing, they should also take care to ensure that they do not leave some artifacts, especially smaller ones, at the bottom of the water basin. This is especially important if they reuse the basin to wash another batch of artifacts from a different context, thus risking contamination of one batch with artifacts from another.
Note that there can be special requirements for the disposal of dirt removed from artifacts, notably if the artifacts are imported from another country. Rather than disposing of removed dirt down the drain or in regular garbage, preventing possible import of crop diseases requires its disposal by incineration or after baking in a kiln.
Sometimes dripping a mild acid (e. g., 5% acetic acid) on the surfaces of artifacts that have calcareous encrustations will loosen these and make them easier to remove mechanically. Take care, however, not to damage the artifact’s surface below. Also make sure that you neutralize any remaining acid afterward or rinse the artifact thoroughly with distilled water.
Some classes of artifacts that casual cleaning could severely damage include most metallic ones, such as coins, wood, textiles, and even bone tools. They almost always require consultation with a trained conservator.
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