Now that we have explored why we digitise, and the important distinction between a digital file and a digital asset, we should examine HOW we digitise. Of course, like so many things in life, this process is reliant on having access to the correct digitisation equipment.
It has to be said that while the digitisation process can be tailored to your financial situation, it is not for the fainthearted or those who balk at large financial outlays. This becomes even more apparent if you are taking the process seriously enough to want to adhere to any of acknowledged industry best practise guidelines.
At the Chester Beatty we examined the two most prominent of these guidelines, namely: the American Federal Agencies Digital Guidelines Initiative (FADGI) and the Dutch Metamorfoze guidelines. These guidelines are terrifyingly scientific with lots of discussion about topics such as illuminance non-conformity and reproduction scale accuracy but as one engages with their standards it becomes reassuringly comprehensive. Cutting through the technical jargon means illuminance non-conformity and reproduction scale accuracy becomes the ways and means to test how even your lighting is and how well represented the size of your object is within your image.
It also means that you’re able to narrow down the equipment one might need. If one wants to be able to produce images that are compliant with the highest level of these guidelines the camera you use will need to have at least a bit depth of 16 bits. Similarly, the camera needs to be of a high enough resolution to create images where all of the tiny but essential details present in the objects can be visible.
This is why we at the Chester Beatty have decided that the Phase One IQ380 digital back is the one that allows the greatest balance of cost and resolution. The large 80mp sensor is able to capture incredibly fine detail that not only complies with the FADGI and Metamorfoze guidelines but allows tiny details to be magnified and examined very closely. It would also allow us access to the Schneider Kreuznach leaf shutter lens line up, arguably the sharpest lenses available for medium format photography.
Almost as important as the camera and lenses to the digitisation process are the lights used within the studio. These lights need to be carefully selected for a number of reasons. Firstly, when working with fragile and valuable objects it is possible for the heat produced by some lights to actually damage the objects. The heating up of the lights can cause a second problem in that it often causes the colour temperature of the lights to shift slightly. This can be a problem with digitisation as colours need to be kept as neutral and realistic as possible. Finally, the light’s refresh rate must be considered as some photographers need to take multiple shots in rapid succession and not all flashes are capable of this.
To answer these questions we held discussions with the Chester Beatty’s conservation department about what level of heat dispersion and light illuminance would be permissible with our irreplaceable and very fragile collections. Despite the great improvements in constant lighting there was a degree of scepticism held towards constant lighting both of LED and fluorescent origin, as there was a worry that they might heat up more than is acceptable. Similarly, after discussions with the digitisation department at Trinity College Dublin and the Bodleian Libraries of Oxford University it was felt that constant lighting still was not entirely reliable with regards to colour shifts.
After much “umming and ahhing” we decided upon a rather comprehensive lighting set-up, the backbone of which is the impressive Profoto D4 4800W Air Generator. This power pack, while being one of the most powerful on the market, has a number of features we decided were very useful to us. An important one being the way it has built in communications ability with Phase One cameras. This lets us fire the lights as well as control their intensity through the camera body without the need of annoying sync cables or even a wireless remote. More important to us though was the pack’s renowned colour stability, a strength that would allow us to shoot for long periods of time without worrying about any shifts in the light’s colour output or intensity. To round out the set-up we also bought three flash heads and a ring flash; these would allow us the greatest flexibility to light the variety of objects we have in our collections.
With those important decisions made we were well on our way to fully equipping our digitisation studio.
Jon Riordan, Digital Photographer at the Chester Beatty