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DIAMM FIRST SLIDEThe Digital Image Archive of Medieval Music

www.diamm.ac.ukProf Andrew Wathey (Royal Holloway)

Dr Margaret Bent (All Souls, Oxford)

Dr Julia Craig-McFeely (Royal Holloway)

Dr Marilyn Deegan (CCH, King’s London)

Centre for Computing in the Humanities

(Harold Short, Gerhard Brey, Paul Vetch, Arianna Ciula, Elliott Hall, Paul Spence etc.)

Fiona Shand (Magdalen College, Oxford) research assistant

Dr Lynda Sayce (Oxford) project photographer

Funded by

The Arts and Humanities Research Board 1998-2004

The Andrew W Mellon Foundation 2002-2006

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Creating digital materials

Why are we digitizing?

• Is it to provide scholars with working copies? (= microfilm/slides)

• Is it to create a record of the document? (= good glossy photos)

• Is it to preserve the document from further handling and create a surrogate that could

replace the original if it was lost? (= full-size colour Ektachrome?)

Define the original in order to define usage and therefore resolution.

• Are you preserving data alone?

• Are you preserving the artefact so that it can be re-created?

Resolution in relation to the size of the original (i.e. at real size):

• On-screen 96 dpi

• Printable 300 dpi

• Archive-qualty 400-600 dpi and above

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What sort of digitization should archives undertake?

Digitize in such a way that you do not need to go back to the MS

and do it again.

Conservation: limiting use of the document by providing excellent

surrogates

There is no point in digitizing without a clear strategy for storage

and delivery

Digital images should provide something NEW, changing

scholarship and scholars

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Defining quality in imaging

High-street cameras: 5-8 million pixels compact

8-12 million pixels digital SLR

PhaseOne P45 single-shot: 39 million pixels

PhaseOne PowerPhase FX (scanning back): max capture area 144 million pixels

Always take the largest image you are likely to need because you can remove pixels to reduce size, but you cannot put them back to increase size once they are gone, or if they were never there.

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Original40 x 30 cm

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How big is big enough?

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(My) Definition of a good image

IN FOCUS and sharp even in fine detail

Correctly exposed

Colour accurate

Contains all the information you might need to recreate the original AND

fully understand the surrogate:

• Colour scale

• Size scale

• Grayscale if possible

• Has camera profile embedded

Does not need to be adjusted or corrected in any way (e.g. sharpened,

level-adjusted, de-skewed)

Has not lost any information through compression

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Colour/Size scale patches

Allows photographer to ensure correct exposure and colour balance for each image at

point of capture

Gives instant size information (no need to look elsewhere)

Provides user with colour control information when viewing images without the

original source present and assess exposure level and colour cast (if any)

Provides colour control information for accurate reproduction (both hard copy and

digital)

Allows evaluation of image quality after capture

Accuracy of individual file data in the future can be assessed

Provides a printer with control information for creating correct colour and size output

HOWEVER: the colour scale must not touch the subject of the image!

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What are the cost issues relating to quality?

Time = cost

• Including colour and size scale has minimal impact;

• Embedding colour profile of capture equipment has minimal impact;

• Adjusting for fine-focus has small impact if it can be done once per batch;

• Adjusting for fine-focus has considerable impact if it has to be done for every picture;

• High-resolution scanning is extremely costly, but essential for over-sized or damaged

manuscripts;

• Quality assessment at point of capture is time consuming

However:

• A ‘bad’ picture will have to be re-shot, which is extremely wasteful and therefore costly

• Post-processing of any sort is wasteful: if you have to post-process, the capture is

flawed and the picture is not good enough

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What are the difficulties facing the ‘creator’?

We need to balance cost against the value of the end product

We cannot photograph every document in the same way

• A small document does not need the resolution that a large document

requires.

• Photographing a large document without the resolution you need results in

fuzzy pictures.

• Damaged documents require much more detail, since the scholar will

require more clarity to read it.

Is my image big enough?

GB-Stratford, Shakespeare Birthplace Trust DR 37 Vol. 41 (back cover)

GB-Oxford, Corpus Christi College, MS 144, f. 25v

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www.diamm.ac.uk

www.diamm.ac.uke-mail: julia.craig-mcfeely@music.ox.ac.uk