Uncovering these sources requires a range of complementary techniques employed by various specialities: history, architecture, drawing, archaeology and occasionally the tools specific to industrial archaeology. It is, in essence, the process of compilation, analysis and interpretation of testimonials that we know as documentation. However, if we wish to capture as much information as possible in the most effective way, then we must select a combination of techniques suitable to each case.
To simplify the task of designing a project that integrates all techniques to be used, we have created a protocol that organises available documentation into various levels. The left column of the chart contains the main instruments available to us: written records, plans/maps, gathering sources of documentation, photographic records, documents describing industrial processes and oral history. The upper row lists the various levels, from 1 to 5, which correspond to the importance, urgency and budget allotted to the project.
Further explanations are unnecessary, as the chart is fairly straight-forward. By way of example, a Basic documentation project, level 1, could be an inventory of real property. An inventory serves as a quick compilation of relatively superficial information on a large amount of elements. It also serves to expand our knowledge on the heritage of an entire area and is an essential tool in determining policies regarding conservation and research. Thus, the written report consists of providing information as to the location of each element, a brief description and age of each, document research which usually consists of locating old maps; and photographic records that may include an exterior photograph accompanied by a sketch and a summary of the industrial process.
On the other hand, the aim of a level 3 Analytical documentation project is to gain an in-depth understanding of the workings and function of a single important element. This report will include, in addition to the information from previous levels, a full examination and assessment of pre-existing structures. Under plans, we can include detailed drawings of construction elements and machinery accompanied by photographic support. Principal archives must be consulted and an index of documents and maps must be created. Finally, it is important to document all processes, when there still exist testimonials: this involves the preparation a graphic representation of the movement of archival materials within the project, that is, between one section and another, preparation of industrial activity audiovisual recordings—if they still exist—and preparation of an inventory of principal components. The example shown is that of the Llobregat Delta Rice Mill, which was demolished in the river diversion project in 2006.
In urgent cases, when there is a risk of losing the industrial remains, it is more crucial to document the site with maps and photographs. Remaining documents can be subsequently examined once the material records have disappeared.
How do we determine which level is suited to each case? In general, there are three criteria that can be applied: First, the value or importance of the heritage site; second, the urgency of the case, that is, its state of conservation; and third, the resources (which at times, imply budgetary resources) available to undertake the study.
Above all we'd like to stress the importance of capturing the productive activity, that is, the industrial processes. Very often we see reports containing highly detailed descriptions of the buildings and their architectural evolution, accompanied by excellent drawings and glorious photographs, which unfortunately do not provide us with information about what actually occurred at the site. Where there real workers at the site? What exactly did they do? In industrial archaeology, processes are key in understanding the interaction between people and industrial sites.