
46575af1bc4b41e511e6d65645daab1b.ppt
- Количество слайдов: 52
Creating and delivering digital collections University of Brighton 9 July 2010 John Hargreaves
JISC Digital Media is a JISC funded service set up to provide advice and guidance predominantly to the Further and Higher Education community on the issues of creating, delivering and using still images, moving images and sound resources, together with managing digitisation projects.
JISC Digital Media’s Services – Web resources http: //www. jiscdigitalmedia. ac. uk/ – Helpdesk service info@jiscdigitalmedia. ac. uk – Hands-on training http: //www. jiscdigitalmedia. ac. uk/training/ – Mailing list http: //www. jiscdigitalmedia. ac. uk/mailing_list. html – Blog http: //www. jiscdigitalmedia. ac. uk/blog/ – Online surgeries – Consultancy http: //www. jiscdigitalmedia. ac. uk/consultancy. html
Content for today: • Tasks to undertake in planning a departmental image collection • Handling originals • Review of key image properties and formats • Calibration of monitors • File formats • Storage and delivery • Putting it all together
Why build a digital collection? – Expensive – Time consuming – Steep learning curve – Standards not always clear or stable – …
Why build a digital collection? – Efficiency (avoid duplication) – Required for teaching or research – Improve access/ distribution – Publicise resources – Preservation – Generate income – Staff development – Attract staff/students – Collaboration – Demand from managers – Demand from users!
Planning a Departmental Collection Image courtesy of stock. xchng
Why not just get on with it? ”Our model of ‘just do it’ is about to do us in. ” University of Oregon Libraries in RLG Digi. News, December 2005
Before you start….
Do your homework… – What do your users need? (ask them) – What’s possible? (what are others in similar situations doing? ) – What resources do you have? (e. g. existing images, metadata, technologies, skills, budget, time, goodwill… esp. from IT departments) – What about the bigger picture? (e. g. institutional objectives, educational trends, legal context, other collections…)
Have a cunning plan… – Set clear and achievable objectives – Get it all down on paper (user requirements, technical specifications, workflow, timetable, budget, marketing, risk analysis, quality plan…) – Involve any stakeholders
Particular things to think about… – How important are ‘standards’? • E. g. image quality, metadata – Do you want to ‘interoperate’? • Who might you share your collection with? – Should you Do-It-All-Yourself? • Outsource all or some of the project? – Copyright!!! • Thorough investigation is necessary before starting the project
Handling Originals
What type of Original? • • • 2 D 3 D Macroscopic Microscopic Primary source Surrogate
Preparation of Originals • Prior to digitisation… • Consider environment, software and equipment • Establish a capture workflow • Agree with conservation that objects are in a stable state • Ensure objects can be provided at sufficient rate • Clean originals
Issues to Consider • Access • Impact of capture conditions • Special requirements • Fragile • Unsafe • Awkward • Additional resources • Added time to workflow
How Should your Original be Handled? • Is it suitable for being pressed on a flat bed scanner? • Is it suitable for disbinding? • Slides and photographs should be handled carefully and always by their edges • Do not drag materials across scanner glass
Outsourcing Capture • Maybe more cost effective to outsource the digitisation of large quantities or fragile originals • Consultancy – Advise clients how to optimise in-house resources for digitisation projects
Digital Images Image courtesy of stock. xchng
Resolution – Best to think about absolute number of pixels in your images rather than thinking in terms of dpi – unless scanning or printing. 256 samples 128 samples 32 samples 8 256 samples 128 32 8 Image: JISC Digital Media
What Resolution is right? – Depends entirely on context – Digital capture resolution: • Scanning large photos at 600 dpi on a flatbed is generous • Scanning slides at 600 dpi is insufficient – Digital output resolution: • A 600 pixel image might fill much of a laptop screen or Power. Point slide • A 600 pixel image will only be 2 inches long printed at 300 dpi
An Image Output to a Monitor 6 x 4 inch photo sampled at 100 pixels per inch 600 768 800 1024 How big? 600 x 400 pixels How big on screen? Depends on screen size (setting)
Image when printed 6 x 4 inch photo sampled at 100 pixels per inch How big? • 600 x 400 pixels How big when printed? 300 dpi
Bit Depth – What you should know – Every pixel is represented by one or more ‘bits’ – Bits are binary and have only two values “ 0” or “ 1” – For a 1 -bit image each pixel records either a single“ 0” or a “ 1”. This gives a “bitonal” image. E. g. “ 0” = Black and “ 1” = White – The more the bits you allow for each pixel, the bigger the tonal range (and the bigger the file) – 8 bits per pixel will enable 256 possible values, creating the impression of continuous tone (“grayscale”)
Bit Depth – “Bitonal” to “Grayscale” 1 -bit 2 -bit (2 shades) (4 shades) 4 -bit (16 shades) 8 -bit (1 byte) (256 shades) Images: JISC
What about colour? “ 24 -bit colour” = 8 -bits per colour channel (256 shades of Red x 256 Greens x 256 Blues) = 16. 8 million potential colours = Images: JISC Digital Media
Calibrating your Monitor Calibration: • The process of correcting the colour rendition settings of a monitor to match desired colours of the output device. • Away from bright light sources that might reflect off your screen • A consistent ambient lighting • A neutral environment and a neutral (grey) desktop
Calibration Hardware • There is a small range of optical hardware available. • These devices attach to the screen and read the monitor output • They compare measured values from the screen with “known” values • A profile is created and loaded into the OS to compensate for differences
Storing and Delivering Your Collection Image courtesy of stock. xchng
File Formats – Different formats suit different kinds of images and different tasks: – Established formats: • TIFF – high quality, holds 48 -bit+ colour, suitable for archiving, not suitable for Web delivery • JPEG – compromised quality, holds up to 24 -bit colour, ideal for photo-realistic images, Web delivery, care needed when compressing images • GIF – simple format, only hold up to 256 colours (8 -bit), ideal for graphics with flat colour, Web delivery • And newer formats……
File Formats – Newer formats • RAW and DNG formats – effectively digital negatives • JPEG 2000 and PNG formats – next generation JPEG and GIF – suitable as both archiving and delivery formats due to lossless compression and higher bit-depths
File Naming – Several different options: • Meaningful names (e. g. french_expedition_2005_01. jpg) • Unique identifiers (e. g. 00000023. tif) • A mix of both (e. g. 05 a 0001 t. gif) • Append original names if relevant (e. g. roman_vase_08579. Cr 2 or roman_vase_08579_opt. tiff) • My own choice (081107_BDICgrp_01392_kilbey. ext) Photograph courtesy of stock. xchng
Automating tasks for your collection – Photoshop, Lightroom (and some other programs) will let you batch process large quantities of images – Useful for: • Adding common/shared metadata • Performing ‘universal’ edits such as changing file formats
What metadata to collect • Descriptive/ Discovery metadata e. g. “Title”, “Subject” Used for finding resources • Admin, technical, preservation metadata e. g. ”Format”, “File size” Used to create, manage and preserve resources
What metadata to collect (cont) • Structural and packaging metadata e. g. “is part of”, “Master image locator” Used to organise resources • Usage and contributed metadata e. g. “Published in”, “Licensed to” Used for license purposes
What metadata to collect (cont) • A Funder might require specific metadata Images for Education http: //imagesforeducation. org. uk/
Vocabularies • Why use them? • Ways to control vocabularies
Why use controlled vocabularies? • • Better retrieval Improved cataloguing efficiency and consistency ‘Disambiguate’ the language e. g. ‘bank’ Put things in their place e. g. classify, identify relationships • Support interoperability and improve cross searching and metadata sharing
Ways to control vocabularies • • Data entry rules Formal subject headings Thesauri Classifications Authority lists (people, places, events) In-house keyword lists ‘Free’ keywords added by a cataloguer Combination of approaches
Storing and Delivering Your Collection Image courtesy of stock. xchng
Requirements and Resources – Your choice of a system will be determined by your requirements and resources: • What does it need to do? • How soon do you need a system? • Does your system need to integrate with other systems? • How much can you afford to pay? • Do you have access to good IT support/ programming? • …
‘Low-tech’ Approaches – – Careful file and folder naming Spreadsheets Metadata embedded within the image file Simple ‘folder viewers’ (e. g. Windows folder view…
‘Low-tech’ Approaches – Free or cheap to buy – but might prove expensive in terms of time (few productivity features) – Quick and (fairly) easy to implement – though might add time later on (e. g. migrating data to another system) – May be: (a) all you need for now, (b) an interim solution, or (c) something to use alongside other systems
‘Off-the-shelf’ Solutions – Commercial Image Management Systems • Large range of products (Canto Cumulus/Mediadex, Extensis Portfolio, Fotostation, Imatch, Expression Media…) • Often deal with more than just images (“digital asset management” systems – DAMs) • Often come in a range of sizes and prices (standalone, server/workgroup, Web publishing…) • Usually come from outside education/heritage sectors (e. g. business, photographic market) Image courtesy of stock. xchng
Custom ‘Solutions’ – Get someone to build you a system: • Sometimes built using standard database and Web technologies • Sometimes proprietary systems tailored to meet your specific needs – Pros and cons: • Might be better match for your requirements, but might not offer all the functionality of an off the shelf system at a similar cost • Likely to take a lot of time and management • Can be issues with documentation, ongoing support and upgrading the system Image courtesy of stock. xchng
Using Existing Systems – Manage your departmental collection using another system within your institution: • Proprietary library, archive and museum management systems typically now offer image/media modules • Repository Systems (e. g. DSpace) • Content Management Systems • Virtual Learning Environment (VLE) … – Pros and cons: • Might solve your problems and open your collection to wider audiences, but likely to be political issues, technical limitations, or compromises Image courtesy of stock. xchng
Putting it together Image courtesy of stock. xchng
‘Workflow’ g g g Useful to list (or draw diagram of) all the steps involved in adding images to your collection Make sure you consider documentation required to support all these steps (e. g. selection criteria, cataloguing notes) Make sure you build quality assurance (QA) checks into the workflow
‘Workflow’ – JISC Digital Media’s sample QA workflow http: //www. jiscdigitalmedia. ac. uk/advice/creating/qassurance. html
‘Workflow’ g g g You should QA both images and metadata (though not necessarily 100%) Make sure you’re fully exploiting the technology (e. g. batch processing, metadata templates, automated spellchecking, calibrated monitors…) Don’t expect anyone to scan or catalogue 7 hrs a day, 5 days a week…
‘Workflow’ g g Artists/Photographers don’t necessarily make the best image editors Subject experts don’t necessarily make best cataloguers… …nor do librarians Consider how you might also exploit your users (QA, metadata tagging, Web 2. 0…)
Keep in Touch – Further Support and Guidance • Web site: www. jiscdigitalmedia. ac. uk • Helpdesk: info@jiscdigitalmedia. ac. uk • Mailing list: www. jiscmail. ac. uk/lists/jiscdigitalmedia. html
46575af1bc4b41e511e6d65645daab1b.ppt