Slide Scanning Converting Your Film Photographs to Digital Presentation to UCHUG - 8/06/08 G. Skalka
Why Scan? Film and prints degrade - bits do not Infinite identical copies of digital image Storage space is reduced Easier to edit and enhance digital photos Easier to view (with computer vs. projector) Easier to share
Film Photography Color photographic film contains three emulsion layers Each contains silver salts that are sensitive to a particular frequency range (color) of light Blue, Red and Green are recorded separately Colored dyes replace the silver salts in the film during developing, forming color images The dyes break down over time, accelerated by heat and light
Film Types Negative Film Produces color negatives, from which color prints are made Most cost-effective film type when prints are needed Reversal Film Produces color transparencies (slides) Less expensive to use than negative or print film (unless prints are needed)
Film Size 35 mm (also called 135) was and is the most popular type of roll film 35 mm wide film strip Image size is 36 mm x 24 mm
Digital Photography Images are recorded in pixels, the smallest piece of information in the image Digital cameras use an image sensor to convert the visual image directly to digital bits Sensors consist of a large number of single sensor elements, in an array Scanners use image sensors to convert the image recorded on film to digital
Resolution Rendering an optical view (in a digital camera) or image (in a scanner) with more pixels (higher resolution) results in a more accurate representation Digital Camera Resolution Measured in pixels (or typically megapixels) 3072 x 2304 pixels provides 7.1 megapixels
Resolution Scanner Resolution Measured in dpi (dots per inch), or more accurately, ppi (pixels per inch) or spi (samples per inch) Film Resolution Measured in lines, the number of adjacent lines (paired as one light and one dark) that can be resolved). Photographic film has 3000-6000 lines per inch.
Resolution Print Resolution Measured in dpi Typical resolution for photographic print paper is 300 dpi
Should You Scan Prints or Film? Film is original - Print is second generation copy Film is higher resolution (10x, 3000 dpi min. vs. 300 dpi) At 300 dpi, the equivalent full-resolution print from 35 mm film would be 14 x 9.4 Only scanning a large print yields a better digital image (assumes scanners can take advantage of full resolution in each case)
If Scanning a Print Makes the Most Sense Scan the largest print available Make sure the scanner glass is clean Scan at 300 dpi maximum At 300 dpi print resolution, no additional information is available for higher resolution scans Higher scanning resolution makes file size unnecessarily large
Film Scanning Options Two basic choices Flatbed scanner with transparency adapter Dedicated film scanner Third choice - use a scanning service
Flatbed Scanners Require a transparency adapter to scan film An additional calibrated light source opposite the film from the sensor Light from transparency adapter passes through film to sensor Light must also pass through glass plate Resolutions of 4800 dpi to 9600 dpi $80 to $500 Can also scan prints and documents
Film Scanners Dedicated to slide / negative scanning (typically 35 mm only) Generally higher image quality for film Resolutions up to 5400 dpi $100 to $5000 Can include auto-feed for both mounted slides and strip film
Film Scanning Service You send in film - they digitize Can provide digital editing and optimization Can provide on CD, DVD or online $0.50 - $0.90 per slide or negative Many services available - probably many results as well Ask about scan resolutions and file formats
How Much Resolution is Needed? 35 mm film is 3000 to 6000 dpi, or equivalent to 12 to 48 megapixels To print from scan of film 11 x 14 print requires minimum 3000 dpi scan or 12 megapixel file 8 x 10 print requires minimum 2400 dpi scan or 7.7 megapixel file 5 x 7 print requires minimum 1400 dpi scan or 2.6 megapixel file
Digital Image File Formats PNG - Portable Network Graphics -.png Lossless compression - approx. 75% of TIFF Fairly well supported TIFF - Tag Image File Format -.tif Uncompressed; can have lossless compression Most universal commercial format JPEG - Joint Photographic Experts Group Lossy compression provides files 10% of TIFF Most popular for digital photo exchange
What File Format to Use? PNG or TIFF for archiving JPEG for displaying or sharing I recommend storing masters as PNG, and converting to JPEG for use and display Not all my scanning software supports PNG, so conversion from TIFF may be necessary I may need to look for better scanning software
My Four Film Scanners HP ScanJet 5370 Cxi Flatbed w/tma 1200 dpi (1.9 megapixel), $300 in 1998 PrimeFilm 1800u Film Scanner 1800 dpi (4.4 megapixel), $120 in 2003 Microtek ScanMaker S400 Flatbed w/tma 4800 dpi (30.8 megapixel), $80 in 2006 PrimeFilm 3600u Film Scanner 3600 dpi (17.4 megapixel), $120 in 2008
HP ScanJet Cxi Flatbed 1200 dpi flatbed, scan time = 1 min
HP ScanJet Cxi Flatbed Has transparent media adapter (TMA) and holders for both mounted slider and strip film / negatives
Test Slide
Resolution Test 75 dpi 0.7 MB 300 dpi 10.2 MB 100 dpi 1.2 MB 150 dpi 2.6 MB 600 dpi 37.4 MB 1200 dpi 123.8 MB 200 dpi 4.7 MB Auto (200 dpi) 4.7 MB
Test Negative (as Slide)
Test Negative (as Negative)
Pacific Image Electronics PrimeFilm 1800u 1800 dpi film scanner Subset of 3600u capabilities
Microtek ScanMaker S400 4800 dpi flatbed, scan time = 4-9 minutes
Microtek ScanMaker S400 Has transparent media adapter (TMA), which holds both mounted slides and strip film / negatives
Resolution Test 100 dpi 0.042 MB 1200 dpi 5.1 MB 150 dpi 0.088 MB 300 dpi 0.33 MB 2400 dpi 19.5 MB 3200 dpi 33.9 MB 600 dpi 1.3 MB 4800 dpi 72.7 MB
Test Negative (as Slide)
Test Negative (as Negative)
Pacific Image Electronics PrimeFilm 3600u 3600 dpi film scanner for film and slides Scan times of 1-4 minutes
Resolution Test 72 dpi 0.022 MB 1800 dpi 9.8 MB 300 dpi 0.32 MB 720 dpi 1.7 MB 2400 dpi 18.1 MB 3000 dpi 28.0 MB 1200 dpi 4.5 MB 3600 dpi 39.7 MB
Test Negative (as Slide)
Test Negative (as Negative)
Relative Negative Scan Quality HP Microtek PrimeFilm
Relative Resolution Quality 1200 dpi HP 4800 dpi Microtek 3600 dpi PrimeFilm
Scan Capacities HP can scan 1-4 mounted slides or 1-8 strip film images (negatives) Microtek can scan 1-4 mounted slides or 1-6 film images (negatives) PrimeFilm can scan 1 mounted slide or strip film image
Scanning Multiple Images Reduces loading time per scan Scanning time is proportionally larger than single slide Photo editing software time is required to crop and save individual images separately
Develop a Scan Methodology Determine the minimum resolution you need For future printing For display and general use Consider scanning at multiple resolutions High resolution for important or significant photos Lower resolution for less significant shots Consider which slides are not significant enough to warrant scanning at all
Hints for Better Scans Clean the glass on flatbed scanners Blow dust out of film scanner with canned air periodically Remove dust from film with a photo brush or canned air just before scanning
Acknowledgements World Book Encyclopedia, Photography, 1970, Field Enterprises Educational Corp. Wikipedia - 135 Film, 35 mm, Image Resolution, Pixel, Image Scanner Scantips.com, Wayne Fulton Hewlett Packard, hp.com Pacific Image Electronics, scanace.com