First Thing's First: What Tools do I need?
- After you have determined the main considerations, such as selection of the photographs you want to digitize, copyright evaluation and possible pre-treatment of original photographs, there needs to be an assessment of what types of tools you will need to successfully complete a photo digitization project.
Equipment
· Scanner or camera
· Printer
· Hardware
· Software
Scanners: Consider a scanner system that provides the best digital images a possible. Other considerations include reproduction and preservation.
Key Criteria:
· Type of Scanner appropriate for your materials
· Technical capabilities of scanning system
· Budget for scanning equipment and software.
( Peterson, 2009, What to Look for in a Scanner)
Spatial Resolutions: (Detail and edge reproduction) The scanner chosen should be able to give the desired spatial resolution, which is the rate at which an image is sampled during scanning. The frequency of pizels used to cpture sample tones in the space of the oject being digitized. More pizels per inch means a higher resolution, but overall image quality cnnot be determined by spatial resolution alone.
Tone Resolution
Bit Depth Capture and Output: The bit-depth is the number of bits assigned to a single pixel and determines the number of colors from which a particular pixel value can be selected. The scanner needs to capture a higher bit-depth than the bit-depth specified for the digital image. Common choices for a minimum bit-depth are 8-bit for grayscale and 24-bit for color.
Dynamic Range / Flare: This affects the scanner’s ability to represent the full tonal values of a variety of photographs. The scanner should match the dynamic range of the photographs being copied.
Signal-to-Noise Ratio : Noise is unwanted variations of data or bits in the signals. Signal variations within the scanner create digital image noise during photograph scanning that may cause damage to the tonal values of the digital image.
Color reproduction
Choose a scanner that supports and represents the color space choice for the digital images.
Color Space should be:
· Cross-platform compatible.
· Open and well documented
· Widely implemented and supported
Types of scanners:
The drum scanner Drum scanners use photo-multiplier tubes (PMT) to produce very high quality results. They typically have a density range of 3.4 - 4.0 with a 'dMax' at the top of that range. They can offer an optical resolution of up to 8000 samples per inch (spi). Drum scanners are the tool of choice of the print industry and normally only used by professional digitisation bureaux. This is due both to their expense and their complexity, requiring skilful operation to get the best from them.
Only flexible original artwork can be scanned in a drum scanner as it has to be 'mounted' on a transparent acrylic cylinder (drum) and then spun at high speeds around the photo-multipliers within the cylinder. Mounting transparencies on the drum is a slow and skilled operation and it is normal to have at least two drums in use so that one can be mounted whilst the other is being scanned.
Although the quality from these scanners is exemplary, they tend to be slow and cannot normally provide the level of productivity required from most digitisation projects. There are also some preservation issues with the standard use of a 'mounting oil' to avoid 'Newton's rings' between the transparency and the drum. If a mounting oil is used, then the transparencies must be scrupulously cleaned after scanning.
The flatbed scanner Flatbed scanners use a linear CCD array, made up from a long line of charge-coupled device elements in a row. The CCDs themselves can only detect the presence or absence of light. To enable the scanner to capture colour, they must either make three passes with a Red, Green or Blue filter in front of the CCD or have 3 lines of CCD each with either a red, green or blue filter on top.
CCD based scanners are much cheaper to produce than PMT based scanners and also tend to be much easier to operate. They range from very cheap and low-end consumer devices right up to professional quality devices with costs comparable with cheaper drum scanners.
For the digitisation project one of the main advantages of the flatbed scanner is that they are generally much simpler to use, allowing unskilled operators to effectively use them without many weeks of extensive training. The flatbed scanner is also much more acceptable in conservation terms as the original does not need to be bent around a drum (and then taped down!), nor does it need any mounting oil to avoid Newton's rings. Any artwork that can be safely placed face down flat on the scanner can be quickly and easily scanned.
Flatbeds also offer much faster scanning times than drum scanners. This, along with the lack of any required preparation (mounting transparency on drum with tape and oil) makes it much easier to establish a productive and speedy workflow.
Most high-end flatbed scanners normally offer the ability to scan both reflective and transparent originals, whilst mid-range devices normally need a separate transparency media adapter (TMA) to scan slides and transparencies. Most low-end flatbed scanners are only able to scan reflective originals and even if they can be made to work with transparencies are unlikely to have the necessary optical resolution to provide anything more than the most basic quality.
The optical resolution of flatbed scanners is largely dependent on how much you want to spend on them. High-end flatbeds are capable of producing 5,000 spi, almost as high as comparably costing drum scanners, whilst at the low-end of the spectrum, the available resolution of consumer devices appear to improve every month and currently stands at around 2400 spi.
The transparency scanner Transparency and slide scanners again use CCD technology to scan original transparencies. Rather than attempting to provide reasonable quality over a comparatively large A4 bed these scanners are dedicated to just scanning a small transparency to a high quality at a much higher resolution. The smaller and cheaper transparency scanners only scan 35mm film but the larger more expensive models can scan all formats up to 5" × 4".
Transparency scanners can offer resolutions similar to high-end flatbeds with up to 5,000 spi although most low to mid-end transparency scanners typically scan at about 4,000 spi for 135mm slides.
Typically these devices offer a much higher quality scan than can be made with a low to mid-end flatbed scanner but at a price much lower than the high-end flatbed. They are easy and relatively fast to operate with options such as Automatic Transparency Feeders enabling them to provide highly productive workflows.
Transparency scanners therefore offer a good alternative if you need to scan large number of slides/transparencies but do not have the time or budget to operate a high-end flatbed or drum scanner.
http://www.jiscdigitalmedia.ac.uk/stillimages/advice/scanners/
Camera: Cameras may be used to create a negative copy of the original photograph or digitizing the photograph by using a camera instead of a scanner.
Copying: Copying the photograph onto a negative may be achieved through a camera.
1. First, the materials being photographed must be absolutely parallel to the film mounted on to a copy board for stability.
2. Second, the camera needs to be able to provide a sharp focus
· You can reduce or enlarge the image just by adjusting the distance between the materials and the camera.
Film: Orthochromatic films, such as commercial or commercial ortho should provide adequate standards for most copying processes. However, panchromatic films should be used for colored or painted originals.
Filters: Filters can be valuable in copying to help eliminate some faults of the original picture. Filtering is most helpful with stains, discolorations, faded or faint images and texture grains with light colors of yellow, blue, light brown or red.
· Daguerreotypes are reflective and two lights at 45 degree angles being the image out without reflection. Orthochromatic films should be used and a blue filter should help make the image softer.
· Ambrotypes can be photographed within their cases. Reflective surfaces with two lights at 45 degree angles. Orthochromatic films should be used and not filters are required.
· Tintypes are usually very dark and should be as light as possible at 45 degree angles.
· Faded prints needs a high-contrast type developers and use a blue filter to tone down the yellowish color.
· Grained prints need to have a lighting adjustments to avoid shadows by using 45 degree angles or place reflectors in the center of the work being copied and photograph is far enough away from the copy board so the overlapping light covers the entire picture.
Sharfran, A. (1967). Restoration and Photographic Copying: the techniques of copying restoring old and damaged photographs. New York, NY: American Photographic Book Publishing Co.
Digital Cameras:
Many digital cameras today can be very expensive, but there are many available that can provide the basics of what you need to digitize your photographs.
· Imagers are needed to capture the light and change it into a digital image file. The most common types of sensors in digital cameras are the Charge Coupled Device and Complementary Metal Oxide Semiconductor, which are pixilated metal oxide semiconductors made form silicon with sensitivity to light.
· Capture technologies such as, scanning tri-linear array provide the same technology as a scanner and can capture large sized images with quality Area array is using a matrix or grid of CCD elements instead of using CCDs progressively to scan the image within the camera. Single matrix- one shot also uses a grid of CCD/CMOS elements to capture the whole image in one. Very common in many basic digital cameras. The single matrix-macro shift offers multi-shot captures.
Camera Type:
· Consumer compact digital cameras are very common and are used for normal amateur photography used with
the single matrix on-shot type.
· Bridge compact cameras are for cheap entry to digital capture.
· Single Lens Reflex 35mm are cameras provides a wide range of lens.
· Studio cameras offer quality of large pixel dimensions.
Identifying Camera Quality
1. Lens quality (Canon, Nikon and Sony digital cameras)
2. Camera shutters need to be at maximum speed
3. Image preview or review
4. Filters
5. Ship Cooling features so the chip will not overheat.
6. Lighting: flash and consistent lighting
7. Image transfer: ample storage for internal saving
Image-file formats used by digital cameras
· TIFF format is recommended. However, TIFF requires large storage space, but can be immediately down loaded to the computer’s hard disk.
· JPEG is used with most consumer cameras and can be compressed at high rates.
· RAW captures from the cameras its original unprocessed form before anything else has been undertaken and does not take a lot of memory.
Printers: In order to consider a printer for good prints of the photographs you digitize you may need to consult some reviews for printer quality.
DPI are halftone dots per inch or ink droplets per inch and PPI is pixels per inch. As suggested by Ctein, 300 ppi is good enough to look nice and sharp, but the higher the ppi the better.
Hardware: There are many considerations when evaluating your hardware requirements for a digitization projects.
1. First you need to consider your memory of you computer. The memory needs to be at the highest capacity, at least 2 GB or RAM and 360 GB of hard drive storage. The best case scenario is having 6 GB of RAM. Memory is important to consider because many scanned photographs can be large at 16 bits per channel produces 6 bytes of data per pixel. If you scan the original at 8 Bits per channel, that cuts the file size in half, but if your original needs too be scanned at 1200 ppi instead of 600, the file size gets larger by 4 times.
· Considerations: When you are digitizing there are many programs using memory such as, the operating system, the image processing software, and plug-ins for that software.
2. The display should be a CRT or a good liquid crystal display (LCD). (Ctein, 2010, P. 27- 33)
Software: There are also specific kinds of software you will need in order to begin the digitization project. Some of these software considerations include programs for photo restoration like photoshop; image editing software, such as GIMP.
1 Photoshop CS4 www.adobe.com/products/photoshop/photoshop: Provides large amounts of memory and many tools and functions have been improved since the last version, such as photomerge for merging pieces of a single photograph into a whole for lack of larger scanners for larger photographs.; The clone stamp and Healing Brush tools for previewing changes about to be made before the are permanent.
Optimize performance of Photoshop CS3 on Windows XP and Vista: Http://tinyurl.com/3xawjy
Photoshop Elements (Mac and Windows) www.adobe.com/products/photoshope/win/
Helpful Plug-ins:
Contrast Master: $69.95 www.thepluginsite.com/products/photowiz/contrastmaster/
· Altering print appearances
PhotoLift: $40.00: www.pizelvistas.com/photolift/photolift.html
· Detail enhancement
Fluid Mask 3: $149.00 www.vertus.com/fm_overview.htm
· Makes a photograph object by object by dividing regions of a photograph
Polaroid Dust and Scratches Removal: Free www.polaroid.com/service/software/poladsr/poladst.html
For more helpful plug-ins and digital restoration tips consult the following book: Ctein (2010) Digital Restoration from Start to finish
:how to repair old and damaged photographs, 2 edition. Focal Press: Elsevier.
2. GIMP: GNU Image Manipulation Program is a free open source image editing program with simple and advanced image editing tasks. These include, opening images in various file formats, saving image into different file formats, resizing images, rotating images, cleaning and healing, acquiring images directly from a scanner or camera. GIMP Website for more information. http://www.jiscdigitalmedia.ac.uk/stillimages/advice/introduction-to-gimp-image-editing-software
JISC also provides a table of many Image editor programs that are offered online at no cost. These image editor programs include:
Aviary Pheonix
DrPic
FotoFlexer
Luna Pic
Phixer
Photoshop.com
Picnik
PicResize
Pixer.us
Pixir
Splashup
Sumo Paint
Peterson, K. A. (2005). Introduction to basic measures of a digital image for pictorial collections. Prints and Photographs Division, Library of Congress, Washington, D. C. Retrieved from http://www.loc.gov/rr/print/tp/IntroDgtlImage.pdf
