Imaging the Papyri

The basics

We use a stand-mounted digital camera to capture images of the Oxyrhynchus Papyri. The camera setup consists of a high-quality studio camera body with Phase One imaging gear fitted to the back, taking the place of the film holder. The Phase One gear is run via software on the Mac G3 we also use for web design. Thanks to a generous grant, we are now in the process of acquiring new equipment which replaces older, borrowed gear:

The standard lighting setup for the images taken so far has consisted of fluorescent tube units mounted on adjustable rails above and to the sides of the stand base. The papyri housed in the Ashmolean are kept sandwiched between sheets of glass, secured together with masking tape, and we do not tamper with this protection during photography. This glass can lead to a number of problems:

The best compromise we have been able to come up with is this: the glass frame is placed on a lightbox offering muted backlighting: this shows up holes and edges sharply, minimises shadow effects, and can help distinguish between ink traces and material flaws in the papyrus. The proposed new lighting rig should help cut shadows further.

Issues of methodology

What are we trying to achieve?

This project is in many ways inspired by the striking success of American APIS imaging projects. APIS participants have committed themselves to a closely reasoned and interconnecting set of goals: Acquiring high-quality images is the first priority — and a time-consuming process. Securely archived TIFF images ‘future-proof’ the actual collection (fingers crossed it won’t go up in smoke, but it could). Made available to individual scholars, they reduce wear on fragile originals.

But high-quality images take all day to download: the files we are archiving routinely hit around 90 mB. A single image is bigger than the entire hard drive on some older machines still in use! And the highest resolutions (thousands of dpi) are better than we need even for archiving. This makes them overkill for most useful purposes — even for quite detailed consultation. So we’re following the APIS sites in archiving sharp 600dpi TIFF images, and putting lower resolutions images online in JPEG format. 600dpi refers to an actual inch of papyus, as measured with a scale.

But...images alone are pretty useless: pretty, because papyrus is a beautiful medium, but useless, because an isolated image tells us nothing. It lacks interpretative context. So we have to work on ways of associating images with data, and making the data accessible in ways that are useful to working papyrologists. We are fortunate that the papyri we are working with have all been published in a form that is readily available to serious researchers. Nonetheless, we have to meet the online user halfway in finding a path through this mass of data to a particular item.

What are we trying to show?

The issues leading to our worries about backlighting in archive images raise the question: what is it we are trying to show? That is to say: what information do we prioritise? Conversely, what information would we happily lose, or even discard as ‘noise’? Questions of this sort can arise at a number of stages: A picture is worth a thousand words; but that is also to say that every picture tells a particular story. Each image is arguably an interpretation of the original artifact, which contains any number of ‘stories’. These might include: The setup(s) we choose are determined by the kind of ‘reading’ of the original we are aiming to produce. In general, academics look at papyri for texts, meaning it’s the ink traces that really count: the colour of the material, for instance, is regarded as less important. So Duke, for instance, routinely (and quite sensibly) run their images through PhotoShop’s Unsharp Mask filter, increasing the contrast to bring out the ink. We have done the same for our Web images. But colour can be important in deciding which fragments might belong together. So too can alignment of the fibres, worm holes, wear and tear. Any choice of what information to prioritise at all costs is going to be a compromise.

But the user has every right to know what choices we’ve made (or at least be given the information to make an educated guess). So we include scales in our images. This is particularly important for archiving purposes, but is pretty handy in a wider context: just how big is that papyrus? More specialised users may wish to know: how concerned have we been to reproduce colour balance accurately? (How close to ‘natural’ is our lighting rig?) Have we even focused the camera? Colour and grey scales act as a control on our images. In general, only a centimeter/inch rule is left in the cropped, resized images we put online at 150dpi, but the archived versions contain all the information for future reference.

Technical stuff

Camera body:Fuji studio camera
Digital camera back:Phase One unit, by PowerPhase
Camera software:Phase One proprietary software
Computer:now G3, formerly Motorola ‘Starmax’ PowerMac clone
Lighting rig:now LARN, formerly Kaiser RB5004 fluorescent tube units
Scales:Kodak Colour Control Patches, Kodak Gray Scale

Imaging menu / Main menu / Markup