3 STANDARDS#

3.1 STRUCTURE#

3.1.1 This document is structured in line with the organisation of an archive, so documentary, digital and material elements are considered separately. This approach has been taken because although not all projects produce finds or environmental materials, those that do invariably produce a documentary archive, and it would be repetitive to try to organise this document in line with different types of project. Links are made throughout to the processes that inform archaeological projects, as shown above, including monitoring of a project and the receiving and care of the archive.

3.1.2 The documentary archive includes documents and digital material, and each requires different standards in creation and care. Digital material is therefore presented in a separate sub-section of the documentary archive.

3.1.3 If one purpose of a project is to produce a stable, ordered, accessible archive, then that aim must be recognised at the outset. Consistent use of this Guide at all stages of a project will facilitate recognition of this aim, and it is intended that it will increase people’s awareness of their responsibilities towards the archive.

3.1.4 The bibliography lists relevant, detailed standards that should also be consulted and understood.

3.2 THE DOCUMENTARY ARCHIVE#

3.2.1 COMPOSITION#

The documentary archive consists of

• written material eg correspondence, contracts, specifications, notes, records, indexes, catalogues, reports
• drawings; printed, or in pencil or ink
• photographs; eg negatives, contact prints, prints, transparencies, x-radiographs
• digital material

3.2.2 PAPER#

3.2.2.1 SUMMARY OF STANDARDS

1. all paper-based material must at all times be stored in conditions that minimise the risks of damage, deterioration, loss or theft
2. permanent or high quality paper/card and writing materials must be used.
3. all documents must be marked with the project identifier (eg site code) and/or the museum accession number
4. all types of record must use a consistent terminology and format
5. use non-metal fastenings, and packaging and binding materials that ensure the longevity of documents, especially in preparation of the archive for long-term deposition
6. copies of reports and appropriate drafts, with associated illustrative material, must be submitted for inclusion with the archive

3.2.2.2 PLANNING

1. Correspondence, contracts, project proposals, project designs, reports and similar documents will normally have been created on, and printed from, a computer. It is difficult to set standards relating to this process, although it should be noted that printer paper and inks are not recognised as stable. Although it is desirable that such documents are submitted in hard copy, they also form part of the digital archive and can be curated as such. Any documents vital to the functioning of the archive as a reusable resource, and submitted in hard copy, must be printed or copied in a way that offers longevity.
2. The agency involved in the execution phase must demonstrate, to the satisfaction of monitoring agents, that they will work to procedures that ensure the production of a consistent record. This includes use of field manuals that make proper reference to the format of record sheets, plans, etc and the terminology to be applied in recording.
3. It is recommended that project proposals, project designs etc refer to this document as an accepted approach for archive delivery.
4. Intellectual property rights and copyright to all elements of the documentary archive must, if possible, be established at the beginning of a project.

3.2.2.3 DATA-GATHERING, ANALYSIS, REPORT-WRITING

1. It is advisable that all primary records are made on paper of recognised archival quality, of neutral or mildly alkaline pH, and in media, either printed or hand-written, that are equally long lived. It is recognised, however, that this cannot always be achieved. Always use high quality paper for records intended for archiving. Photocopies have a short life-span and must not be used. Pro-forma should be printed, not photocopied, and completed using black ballpoint pen or permanent black ink. Recycled paper also has a short lifespan and is not recognised as permanent for archive purposes.
2. All project records must be produced to a consistent format. It is recommended that pro-forma are used for recording primary data. There are no national standards for the lay-out of record sheets, nor in every case for the information they require, but the following must apply
   1. all record sheets must include the site identifier and/or similar location information
   2. reference to national standards, particularly in the specialist recording of finds information. Use these to ensure that the recognised level of information is recorded, eg in designing record sheets or databases
   3. consistent terminology must be used throughout, so that the same term is applied to the same thing every time (eg do not record some metal objects as copper alloy and others as bronze). Include a definition of terms with the archive if necessary. In some instances local terminologies have been developed, and their use required, eg pottery type series
   4. records must be written legibly and using clear language/terminology
   5. the date of completion of a record, and author, must be included
3. All archive material in the temporary care of project teams or specialists must be kept in the best conditions possible, ensuring protection against fading, damage, damp and loss. It is highly desirable that archives are retained in temporary storage for as short a time as possible.
4. A security copy of written records may be required in the Project Proposal or by the archive repository. This may include microfilming or digitisation. Ensure that these requirements are understood at the outset of a project.

3.2.2.4 PREPARATION FOR ARCHIVE TRANSFER

1. All elements of the paper archive must be classified to identify their function. This is especially important for pro-forma, which must have an identifier and/or title (eg context record sheet).
2. There must be indexes for all parts of the paper archive. Some of these are compiled on pro-forma during data collection, eg running lists of context numbers, but others, such as lists of correspondence included in the archive, will be completed as part of the archive preparation process.
3. The paper archive must be accompanied by an overall contents list.
4. At all stages of management of the written archive, the use of non-metal fastenings, such as plastic paperclips is recommended. Do not use metal fastenings or bindings such as staples and ring-binders, or adhesive tape, when preparing the paper archive for long term storage. Documents of the same type should be bundled together, using the following criteria
   1. fasten paper using plastic treasury tags or plastic paperclips
   2. use a separate title page to mark groups of documents
   3. do not use self-adhesive labels (or such things as stick-on notes)
   4. organise documents of the same type in a logical order (eg record sheets in context order; correspondence in chronological order)
   5. do not fold documents
   6. store documents in acid-free, dust-proof, cardboard boxes, do not store documents vertically

3.2.2.5 CURATION

1. the paper archive must be stored in dark conditions
2. the ideal temperature is a fixed point in the range 13ºC to 19ºC
3. the ideal relative humidity is a fixed point in the range 45% to 60%

3.2.3 DRAWINGS#

3.2.3.1 SUMMARY OF STANDARDS

1. all drawings must, at all times, be stored in conditions that minimise risks of damage, deterioration, loss or theft
2. use polyester based film for drawings
3. all drawings must be marked with the project identifier (eg site code) and/or museum accession number
4. all drawings must identify the subject, and include a scale and, where appropriate, a north sign or other means of location/orientation
5. wherever possible, all original drawings must be included in the archive
6. where possible, store drawings flat

3.2.3.1 DATA-GATHERING, ANALYSIS, REPORT-WRITING

1. use the most stable drawing film available, or low-acid card or low-acid paper. Polyester-based film is recommended because it lasts longer than plastic film
2. original drawings on film must be made with a hard pencil, at least 4H
3. do not ink over original pencil drawings
4. use regular sizes of paper or film for drawings, no smaller than A4 and preferably no larger than A1
5. mark all drawing sheets with the project identifier, drawing number, title, scale, date of drawing, name of the person who drew it and, where appropriate, north sign and site grid and/or appropriate location information
6. include a key to all conventions used for particular elements, colours etc
7. do not use adhesive lettering on original drawings that convey site information as this will eventually fall away
8. publication drawings can be produced to less exacting standards, but they must always be properly marked and produced with stable materials
9. a security copy of written records may be required in the Project Proposal or by the archive repository. This may include microfilming or digitisation. Ensure that these requirements are understood at the outset of a project

3.2.3.2 PREPARATION FOR ARCHIVE TRANSFER

1. the archive must include an index of all drawings, some of which are compiled during data collection, in the form of running lists of drawing numbers which must be maintained during analysis and in preparation of drawings for publication
2. pack drawings so they can be stored flat. Acid-free card folders are preferable for separating groups of drawings. Polyester covers can be used, but use tissue paper to separate the uppermost drawing from the polyester
3. do not use adhesive or tape of any kind

3.2.3.3 CURATION

1. drawings should ideally be stored flat, in the dark, in dust-free containers
2. the ideal temperature is a fixed point in the range 5ºC to 10ºC
3. the ideal relative humidity is a fixed point in the range 45% to 60%

3.2.4 PHOTOGRAPHS#

3.2.4.1 SUMMARY OF STANDARDS

1. photographs must, at all times, be stored in conditions that minimise the risks of damage, deterioration, loss or theft
2. media that can be kept in perpetuity, in their original form, must be used for record photographs
3. all photographs must be marked, or made identifiable with, the project identifier (eg site code) and/or museum accession number
4. all record photographs must identify the subject, and include a scale and, where appropriate, a north sign or other means of location/orientation
5. photographs must be packed using appropriate materials

3.2.4.2 DATA-GATHERING, ANALYSIS, REPORT-WRITIN_G

1. digital photographs are increasingly used for record photography but must only be used as a substitute for photographic film if there is a clearly established procedure for long-term preservation of the digital archive, and if proper measures for the collection and security of digital photographs are followed throughout the life of a project
2. black and white film processed to British Standard 5699 is the archival ideal, as it is recognised as suitable for long-term storage, but colour film is now an acceptable alternative. Use processing companies that develop film to high specifications, as commercial, automatic processing techniques do not meet archival standards and must not be used
3. transparencies should be duplicated to allow the use of one set, while the other can be stored. This is most easily achieved by taking two original photographs rather than making copies later.
4. where appropriate, record photographs must include project and object identifiers, and a scale and direction of view indicator
5. used films should be processed as soon as possible to counter the effects of film deterioration
6. video is not recognised as a record medium of archival quality and must not be used as a primary record, although it can be used as an enhancement to recorded information. If submitted with an archive, it is advisable to transfer it to a DVD, where it will be incorporated into the digital archive and curated as such

3.2.4.3 PREPARATION FOR ARCHIVE TRANSFER

1. photographs should be classified by type of media, with negatives, prints, transparencies, x-radiographs and others categorised separately, as some media have differing storage requirements
2. all photographs, or their holders, must be marked with the project identifier, object identifier (if appropriate), film number and frame number
   1. mark negative holders, not negatives
   2. mark prints on the back using a soft pencil, not ink
   3. mark transparency mounts, not the film
3. the archive must include an index of all photographs, some compiled during data collection, in the form of running lists of frame numbers. These lists must be maintained at all times
4. a photographic index should record the category of film (or create separate indexes for each category), film number, frame number, title and/or subject, the date the picture was taken and who took it
   1. silversafe-type paper envelopes are ideal storage media for negatives and x-radiographs, although the careful use of polyester packets or hangers may be more practicable
   2. store prints in acid-free paper enclosures or polyester sleeves, and/or in archival print boxes
   3. pack transparencies into polyester packets or hangers if they are to be stored in cabinets. Some repositories may take them stored in archival boxes

3.2.4.4 CURATION

1. prints should ideally be stored in archival boxes or dust-proof cabinets, at a fixed point within a temperature range of 13ºC to 19ºC, and a relative humidity of 40% to 60%
2. negatives and transparencies should be stored in dust-proof cabinets, although archival boxes may also be appropriate
3. colour film should ideally be stored in a temperature range of 0ºC to 2ºC, in accordance with BS Standard 5454:2000. This is likely to be impracticable, not least because it is difficult to access them for consultation, and it creates acclimatisation problems. The recommended conditions are a fixed point in a temperature range of 5ºC to 10ºC, at a fixed point of relative humidity in the range 30% to 40%. This temperature range will still necessitate a period of acclimatisation prior to handling
4. black and white film should ideally be stored at a fixed point of temperature no higher than 18 ºC, and preferably much cooler.

The recommendation here is a fixed point in the range 15ºC to 19ºC, and a relative humidity between 30% and 40%. There may still be the need to acclimatise materials prior to handling if conditions of storage vary greatly from those of consultation

3.2.5 REPORTS AND PUBLICATIONS

1. when first submitted, the archive must include a short summary report explaining the background to the project, when it was carried out, by whom, where the project was located, and the results of the work
2. copies of all published material relevant to the project must be submitted with the archive, or sent to the archive repository if the archive has been deposited before a publication appeared
3. restrictions on public access to sensitive material must be identified and discussed prior to archive deposition
4. it is often informative to keep copies of draft reports or publications in the archive, and the archive repository should be consulted to determine whether this is required and which drafts are appropriate. The first draft is often the most relevant. Version control is as relevant here as it is with digital records, and it must be possible to identify each different draft. Do not submit unannotated duplicates with the archive
5. reports and publication text are normally written directly onto a computer, thus becoming part of the digital documentary archive. File naming protocols and version control must be exercised to ensure that different drafts can be identified, see Section 3.2.6
6. all original drawings and photographs prepared for a report or publication must be submitted with the archive, refer to Sections 3.2.3 and 3.2.4
7. copies of all born-digital material created for a report or publication must be submitted with the archive, refer to Section 3.2.6

3.2.6 DIGITAL MATERIAL#

3.2.6.1 COMPOSITION

• the digital archive consists entirely of digital data; example file types are CAD files, databases, digital aerial photograph interpretations, excavation archives, geophysical and other survey data, GIS files, images, satellite imagery, spreadsheets, text files and 3-D data
• transfer and short-term storage media include CD-ROMs, data-sticks or flash drives, DVDs, floppy discs, hard discs, and magnetic tape, which are not suitable for the long-term preservation of the digital archive and should be used only to submit digital material for permanent archiving
• long-term storage must be on permanent servers that are regularly backed up

3.2.6.2 SUMMARY OF STANDARDS

1. all digital storage media must, at all times, be stored in conditions that minimise the risks of damage, deterioration, loss or theft
2. creation of the digital archive must be fully documented, with information such as software used, operating systems, types of hardware, dates, personnel, field descriptions, and the meanings of any codes
3. data must be created according to consistent, accepted standards of terminology, content, format and file naming
4. digital archives should conform to existing standards and guidelines on how data should be structured, preserved and accessed
5. digital files must be regularly backed up throughout the course of a project and in archive
6. all media and files must be free of viruses before archive deposition
7. a digital archive index must be compiled and deposited in digital form with the digital archive
8. copies of digital archives should be deposited in a secure digital archiving facility where they can be curated properly, maintained for the future and accessed easily

3.2.6.3 PLANNING

1. project specifications and the project repository archive deposition standards must establish measures for managing creation of digital data
2. the archive repository must specify that copies of all digital material that can be subjected to further analysis or used for presentation are submitted with the archive
3. the archive repository must specify the types of media in which digital information must be submitted
4. the archive repository must specify the preferred file type for specific types of digital data
5. the project design must include a summary of the types of digital data that will be created or acquired during the project, and media on which they will be stored
6. the project design must specify file formats, as recommended by an approved digital archive repository, that will be used for both the secure archiving and the dissemination of data
7. arrangements must be made to deposit either copies of the digital archive, or a catalogue, with a suitable specialist digital archive repository, which in the UK is often the Archaeology Data Service (http://ads.ahds.ac.uk/) The digital repository must be identified at the outset of a project
8. a clear copyright agreement must be established at the beginning of a project, which will enable the repository to make the digital archive available for future study and/or publication

3.2.6.4 DATA-GATHERING, ANALYSIS, REPORT WRITING

1. data collection must be in accordance with defined internal or national standards for content and format, including use of consistent field names, terminologies etc
2. digital files should be named to reflect their content, preferably incorporating the project identifier, and different versions should be numbered. Consistent file naming strategies should be used, and it is good practice not to use spaces, or non-standard characters such as commas, full stops etc. For advice go to http://archaeologydataservice.ac.uk/project/userinfo/deposit.html#filenaming
3. version control must be maintained, so that it is possible to identify the most up to date version of every file
4. the digital archive creation process must be documented, so that its development throughout the course of the project can be understood
5. all data must be routinely backed up, because during a project digital data may be created on a variety of separate computer hard drives or on a network, and data may be acquired from a variety of other formats
6. back-up and restore procedures must be tested regularly
7. the analysis phase of a project is likely to result in a wide variety of databases, spreadsheets, CAD files etc, and the principles relating to Collection (3.4.5) must apply

3.2.6.5 PREPARATION FOR ARCHIVE TRANSFER

1. a digital archive index, in digital form, must be compiled and deposited with the archive
2. digital files must be ordered into a comprehensible directory structure, with folders named to conventions that aid retrieval
3. a digital archive is usually copied onto temporary storage media (eg discs) for transfer to an archaeological archive repository. Use high quality transfer media, or any other solution likely to reduce risk of data loss
4. pack transfer media to protect from dust and damage
5. transfer media must be marked or labelled clearly and permanently in a way that identifies the project and the contents of each disc, tape, etc and relates to the digital archive index. Adhesive labels must not be stuck directly onto CDs and DVDs, which must be marked with non-acidic, specialised marker pens
6. copies of standards or conventions used in creating the content of digital data files, and in ordering the archive, must be kept with the digital archive
7. transfer media must be checked for viruses and clean before final packing
8. depositors of a digital archive are advised to retain their own copy, at least until it is certain that the archive has successfully been transferred to an approved digital archive repository

3.2.6.6 CURATION

1. archaeological archive repositories such as museums that are not specialist digital media archives should ensure that their digital archives are also stored in recognised trusted digital repositories such as ADS. Trusted repositories may soon receive a form of accreditation, in accordance with the emerging RLG/NARA standard (Research Libraries Group/National Archives and Research Administration); see www.archives.gov
2. it is best practice to transfer the digital archive from transfer media (eg discs) to networked servers that are protected and regularly backed up. If this is not within the capabilities of the archive repository, then it is even more important to copy the digital archive to a trusted digital repository, where this procedure will be carried out
3. if digital storage media are retained, store them in fireproof and, where appropriate anti-magnetic, facilities, and keep back-up versions at a separate location
4. repositories must have a data management system that ensures regular back-up and records how files are stored and labelled
5. the integrity of the digital archive must be monitored, and backup and restore procedures tested regularly

3.3 THE MATERIAL ARCHIVE#

3.3.1 SUMMARY OF STANDARDS#

1. all finds must at all times be treated carefully and kept secure
2. all finds must be cleaned as appropriate to ensure their long-term survival
3. finds must be recorded to a consistent format
4. all metal objects retained with the archive must be recorded by x-radiograph (with some exceptions, including gold or lead)
5. finds recording must classify objects to consistent, accepted terminologies of material and object types
6. all finds intended for deposition with the archive must be marked or labelled, as appropriate, with the project and context identifiers and, where relevant, the individual identifier (eg small-find number)
7. all finds intended for deposition with the archive must be packed in appropriate materials to ensure risk-free, long-term storage
8. the material archive must be stored in conditions conducive to long-term survival of each object

3.3.2 COMPOSITION#

The material, or finds, archive is comprised of four elements

• bulk finds; finds that often occur in quantity, and do not require special treatment or closely controlled storage conditions, eg animal bone, ceramic building material, pottery, shell, slag, stone
• sensitive finds; also known as small-finds or registered finds. These usually require controlled storage conditions, and/or more detailed recording procedures, in situ or after collection. Examples include ancient glass, leather, metalwork, textile, worked bone, worked flint and wood
• human remains; these require specific treatment in accordance with national standards and legislation
• materials recovered from scientific sampling; these are often the product of laboratory analysis, eg environmental remains, thin-sections, microfossil slides

The following standards apply to all elements of the material archive. Specific standards are set out in subsequent sections dealing with particular types of finds.

3.3.3 PLANNING#

1. agencies involved in the collection phase must demonstrate, to the satisfaction of monitoring agents, that they will work to procedures that ensure production of a consistent record. This includes the use of finds processing manuals that establish the format of record sheets, cleaning, marking etc and the terminology to be applied in classification. Such manuals should also make reference to relevant national standards
2. collection, selection and retention policies must be agreed at the outset of a project, but with the understanding that these may be adjusted as the site is better understood (see Appendix III). Those involved in such decisions would normally be personnel monitoring the project, site and finds staff involved in collection and analysis, and a representative of the archive repository
3. specialists, including conservators, must be identified at the beginning of a project, and consulted as appropriate during the project

3.3.4 DATA-GATHERING#

This includes the recovery of finds, initial cleaning, classification and sorting, primary recording and initial packing.

1. recovery must be undertaken to current standards of care, avoiding damage, cross-contamination of contexts, and loss or theft
2. recovery should be in accordance with collection and retention strategies agreed and documented at the outset of the project
3. finds must be cleaned to recognised standards, using methods described in nationally recognised documents, (eg First aid for finds). Bulk finds especially may be subject to over-cleaning, leading to the removal of residues etc, so it may be appropriate to assess cleaning requirements at the outset
4. finds intended for retention with the archive must be marked with site and/or context identifiers, as appropriate. Where the size or stability of individual objects precludes this, use tie-on, rot-proof labels or store them in marked containers that contain rot-proof labels carrying relevant information
5. pack finds to ensure that finds from different contexts are kept together, and to protect against loss or damage
   1. bulk finds of the same material type, from the same context, may be packed together in stable paper or polythene bags of suitable weight
   2. mark all bags on the outside with site and context identifiers and the material type, and include a polyethylene label marked with the same information. It may not be possible to mark some polythene bags, in which case they must contain two marked polyethylene labels
   3. use permanent ink on bags and labels
   4. bulk finds may be boxed together, but it is inadvisable to place heavy and delicate objects together in the same box
   5. sensitive finds must be packed individually in bags or boxes marked with the site identifier, context number and/or find number, and if appropriate the repository accession number
   6. sensitive finds must be supported, where appropriate, on inert plastic foam or acid-free tissue paper, designed to prevent movement within the box. It is not advisable to wrap objects in tissue because the act of unwrapping could cause damage
   7. fragile finds, or those that are not marked or have a tie-on label, must be packed to be visible without removal from their container
6. specimen finds, eg those used for analysis, must be packed in containers marked with site and context identifiers. A note detailing the removal of the specimen must be attached to or inserted into the container of finds from which the specimen was extracted
7. human remains must be treated with respect, in accordance with national guidelines. Human skeletal remains must be marked. Apply protocols for the storage, management and examination of human remains that recognise their sensitivity
8. conservation work, including cleaning sensitive finds, must be carried out by ICON-accredited conservators
9. all finds must be sorted and classified according to accepted systems of terminology, of both material types and object types
10. primary recording must facilitate an understanding of the character and extent of the assemblage. Initial finds records must identify material and object types, and quantify each type as appropriate, preferably by two measures, normally weight and fragment count
11. most metal objects must be recorded by x-radiography. Exceptions include
    1. lead alloys or copper alloys with a high lead content
    2. objects too thick to be x-rayed effectively
    3. objects, such as modern finds, for which x-rays will add no useful information
    4. finds of no archaeological significance, eg unstratified
    5. every example of a large homogenous assemblage, eg nails
12. all finds must, at all times, be stored in conditions that minimise the risks of damage, deterioration, loss or theft
13. transfer of finds from one location to another must be undertaken with due care and attention, and must be fully documented

3.3.5 ANALYSIS AND REPORT-WRITING The analysis and interpretation phases relevant to the material archive include specialist study, detailed conservation and scientific analysis.

1. specialists, conservators, and scientific analysts must comply with current standards of object care, minimising the risk of damage, loss and theft 2. specialists must follow accepted standards for recording finds, both in terms of what is recorded and terminology 3. type series created during analysis must be submitted as part of the archive, accompanied by appropriate documentation 4. conservation work, including cleaning sensitive finds, must be carried out by qualified conservators 5. scientific analysis must be carried out by properly qualified practitioners 6. when necessary to transport finds, eg to or from specialists, finds must be packed appropriately and carried by project staff or trustworthy carriers 7. all records and reports relating to the specialist study of finds, conservation and scientific analysis, must be submitted with the archive 8. records and reports are usually created with a computer and will form part of the documentary digital archive. Refer to 4.2.6

3.3.6 PREPARATION FOR ARCHIVE TRANSFER 1. finds must be ordered according to their material type, packing and storage requirements. Bulk finds, sensitive finds, human remains and samples should be kept separate 2. the material archive must be boxed in standard sized boxes as specified by the archive repository

3.3.7 CURATION 1. all finds must be stored in the dark 2 finds must be stored in conditions that are not susceptible to wide fluctuations in temperature or relative humidity (RH) a. bulk finds remain stable at low and high temperatures, and low and high relative humidity, but they must not be subjected to variations in either. Ideal storage is at low temperatures (around 15º C) and 35% to 70% RH b. metals must be stored in a range of 15º to 24º C, and below 35% RH c. organic finds (leather, textile, wood, worked bone) must be dried out before deposition with the archive and stored at 18º to 22ºC and 45% to 55% RH

3.3.8 HUMAN REMAINS

1. projects excavating human remains that require a licence or directions from the Department of Constitutional Affairs may be set a time limit for analysis and may also be required to rebury. This must be understood by all parties involved with the project archive 2. human skeletal remains must be marked with site and context/skeleton identifiers in indelible ink 3. pack human remains so that it is possible to distinguish different individuals 4. excavated skeletal remains may be deposited with a museum as long as existing recognised standards for their treatment have been met 5. skeletal remains must be stored in stable conditions with 35% to 70% RH 6. treatment of soft tissue remains should be the subject of specialist advice 7. human remains must, at all times, be stored in secure stores that are accessible only to authorised staff. It is desirable for archive repositories to have dedicated storage areas 8. museums with collections of human remains should develop a strategy for their care

3.3.9 SCIENTIFIC SAMPLES

A wide variety of samples may be taken during the course of a project, and these may be subdivided into two groups

a. samples taken on site for processing during the collection phase. These usually include samples of structures or deposits for dating or environmental analysis b. samples taken off-site to enhance further analysis. These usually include samples of individual objects for a variety of purposes

a. Samples taken on site 1. project planning must establish sampling strategies, recognising the need for subsequent adjustment as appropriate 2. some samples will be taken for analysis rather than retention with the archive, so there may be no requirement for preparing them for permanent storage. Other techniques may result in accumulation of large quantities of small fragments, which may themselves be sampled again in order to retain a representative quantity in the archive. An example of this might be industrial waste, such as hammer-scale, where the scientific value of full retention may not be justifiable. In such cases on-site sampling, or sampling after post-excavation analysis, may be appropriate, but should only occur following consultation with the relevant specialist 3. at the outset the requirements of the archive repository must be established. Some repositories are happy, where appropriate, for individual laboratories to retain any samples they have produced and/or analysed, while others specify which samples must be deposited with the archive. The aim must be to ensure long-term preservation and accessibility of samples 4. the sampling process must be fully documented, providing an understanding of how, why and in what conditions samples were recovered 5. each sample must be given a unique identifier, which must be marked on the object and/or on all associated labels 6. structures may be sampled to gather evidence of types of building material (bricks, clay, mortar, stone, timber) and these representative objects can be archived in the same way as the rest of the material archive 7. samples taken for dating purposes may be destroyed during analysis, leaving no archival material. Dendrochronological cores are one exception, and some dating agencies will ask to retain samples for reference. There is no reason why repositories should require chronological samples to be submitted with the archive, but all data derived from them must be deposited 8. environmental samples are usually broken down for sorting of the objects they contain (mainly plant and animal remains) 9. artefacts recovered from environmental samples must be marked (on the object or with labels) with the site, context and sample identifiers, and packed and stored as appropriate for the type of material and/or object 10. some animal and plant remains (small bones, shell, insects, charcoal, seeds etc) are extracted during flotation and cannot be dried out. It is not desirable for any wet material to be submitted with the archive, but if it is not be possible or desirable to dry it out, wet material must be stored in air-tight containers of 70% IMS, preferably in the dark and refrigerated 11. repositories must have a system for monitoring the condition of wet samples 12. finds from the sorting of dry residues must be stored in bags marked with site, context and sample identifiers, containing a polyethylene label with the same information 13. finds from the sorting of dry residues must be stored in conditions appropriate for the material type 14. soil analysis may result in preparation of microscope slides (eg thin-sections). There is potential conflict here, as some laboratories will want to keep these for reference, while some repositories will ask for them to be included in the archive. An ideal solution is for a duplicate set of slides to be prepared for archive. If this is not possible then the preference must be for the material to be deposited wherever it is most likely to survive in perpetuity 15. column samples may be stored for some time in drainpipes and kept dark and cool, but this does not guarantee permanent preservation, and analysis must be undertaken as soon as possible 16. some on-site sampling (eg C-14), rarely results in any material archive for deposition, but all associated data must be copied into the archive 17. all archived samples must be boxed separately from bulk and sensitive material and stored in appropriate environmental conditions, dependent upon the material type

b. Sampling in analysis 1. artefacts may be sampled for a variety of purposes, and using various techniques, many of which are destructive, and no material will survive for archiving. The sampling and analysis process must be fully documented, however, and all associated records must be submitted with the archive 2. where samples can be archived, it is possible that some specialists will want to keep these for reference, while some repositories will ask for them to be included in the archive. This is especially true of techniques that result in microscope slides, eg thin-sectioning, pollen and diatom analysis. An ideal solution is for a duplicate set of slides or samples to be prepared for archive. If this is not possible then the preference must be for the material to be deposited wherever it is most likely to survive in perpetuity and be easily accessible for further study; in general that should be the archive repository 3. environmental materials preserved by anoxic conditions (eg insect remains or macroscopic plant remains) must be stored in 70% IMS. A drop of glycerol may be added to prevent samples drying out if the IMS evaporates 4. metallurgical samples are worthy of retention and have great potential for further study. They should be cleaned and de-greased. Copper-alloy and silver should be coated with an acrylic resin with a corrosion inhibitor, such as Incralac. Iron should be coated with an acrylic resin with no inhibitor, such as Paraloid B72. Samples should be packed securely, protecting surfaces, and stored dry (below 15% RH for iron, less than 35% RH for other metals) 5. microscope slides must be packed to prevent damage, in boxes designed for the purpose 6. all samples must be permanently marked or labelled, as appropriate, showing the project identifier, sample number, nature of the sample and other relevant information 7. all collections of retained samples must be fully documented, incorporating a description of collection methods and conditions, and cross-referencing of each sample with sample labels, the original artefact, other relevant records such as databases, photographs or drawings, and publications