Microfilmed Newspapers: Selection for Digitization Success

OCLC Online Computer Library Center

Microfilmed Newspapers: Selection for Digitization Success

ALA June 25, 2006

OCLC Preservation Service Centers




Kelly Barrall

OCLC

Brenda Bailey-Hainer

Colorado State Library

Henry Snyder

California Newspaper

Project

ALA June 25, 2006



Kelly Barrall,

Manager Quality Assurance

Joan DaShiell

Sr. Digital Project Manager


ALA June 25, 2006


Selecting Microfilm for a Digital Imaging Project

Microfilm Format

Film Generation

Determining Film Base & Polarity

Evaluating Technical Criteria

Microfilm To Digital – Tips For Success!


Selecting Microfilm for a Digital Imaging Project

1ST Step Determine format of microfilm available


Microfilm Format Determination

35 mm Preservation microfilm

Larger frames/smaller reduction

Negative or positive

Acetate ?

Diazo/Vesicular

16mm/105mm



2nd step Determine generation of microfilm


Microfilm Generation Determination

Archival Master Camera film

1st generation

Negative

Acetate ?



Print Master Duplicate copy

2nd generation

Negative

Acetate ?



Service Copy Duplicate copy

3rd generation

Positive

Heavily used

Acetate ?



3rd step Determine base and polarity of microfilm


Acetate or Polyester Base?

What’s better for digitization?

Microfilm Base Determination


Acetate

Deteriorating

Warped

Brittle

Curled


Dirty

Scratched

Unstable

Easy to tear


Steps to determine if your film is acetate

Hold a woundreel of film up to the light: If opaque (light will not pass through it) the film is most likely acetate

Unwind several inches of film: acetate film tends to curl across the width of the film

Acetic Acid is vinegar. Acetate film that is deteriorating most likely will have a vinegar odor present.

VIEW CURL SMELL


Polyester

Preservation

Stable

Durable



Negative or Positive Polarity?

What’s better for digitization?

Microfilm Polarity Determination


Positive

Usually 3rd generation

Lower resolution

More scratched



Line that separates columns

Heavyscratches

Example: Heavily scratched positive microfilm


Negative

Usually less noise

Better contrast for text and optical character recognition (OCR)


OCLC Online Computer Library CenterExample: digitized from negative microfilm



4th step Evaluate technical criteria


Microfilm Technical criteria

Reduction ratio Newspapers filmed at 20:1

or lower are optimal

Newspapers filmed at a higher resolution could contain small text that is not legible


Microfilm Technical Criteria

Resolution Focus achieved at the time of capture,

measured with a 100X microscope

Poor resolution = fuzzy text = poor OCR


Microfilm Technical Criteria

Density Range Film created to meet preservation guidelinesFilm created to meet preservation guidelines

Film too light or too dark = poor OCRFilm too light or too dark = poor OCR

Film with uneven lighting = poor OCRFilm with uneven lighting = poor OCR


Example: Uneven lighting – lost text

Lost text


Review Steps 1 - 4

Microfilm Format—35mm

Microfilm Generation—archival, print master, service copy

Microfilm Base & Polarity—acetate vs. polyester; negative vs. positive

Microfilm Technical Criteria—reduction, resolution & density


Tips for a successful microfilm to digital project

Know your microfilm Quantity

Quality

Contents



Quantity Frame count = 1up/2up

Targets

ISE intentional second exposures

Duplicates



Quality Poor original

Poor filming

Poor condition of the film



Contents Newspaper format

Size of the paper, including supplements and full page spreads

Was it filmed bound?

Title changes, should it be treated as one?


Review tips for success!

Quantity – how many images do you really have

Quality – poor quality film = poor quality images

Contents – bound newspapers and title changes



Microfilm to digital


Digitization and imaging options

Duplicate to polyester

Image enhancement

Dynamic threshold adjustment


Questions?

Kelly Barrall/Joan DaShiell1-800-773 7222

Documents

Microfilmed Newspapers: Selection for Digitization Success