Understanding Scanning
NOTE: This article was originally posted as an appendix and supplemental material to Photoshop: In-Depth Healing Tools in conjunction with Carol Rhodes.
With digital camera photographs, there is very little preparation involved to work with them in an application like Photoshop. Many times, it is as simple as plugging a cable into the camera and then into your computer. The rest of the process is frequently accomplished automatically, or with very little direction.
However older photographs must be scanned in for the computer to be able to use them. You might think, “I’ll never need to work with old photographs, I have my digital camera.” But considering photography has been around for more than a century, and digital photography has only been the standard for a decade or so, there are millions of printed photographs still around that are deteriorating everyday. If you want these photographs to last into the next generation, you need to preserve them digitally.
The problem with print photography is that it was growing and changing constantly throughout it’s lifetime. Many of the developing techniques used by early consumer cameras are unstable, and the chemicals used can breakdown over time. Look at any old photograph. The ‘sepia tone’ effect that we associate with older photographs is actually the deterioration of the chemicals used to develop the photograph. Left unchecked, eventually the image will be unrecognizable.
Considering that many print photographs are stored in shoe boxes in closets and under beds, it’s even more important to preserve the images we want to last forever.
In this article, we will examine scanners, including what types are available to consumers, and what features to look for. Finally, we will discuss the best practice to follow to ensure you get a good scan.
A scanner is a piece of computer equipment that works something like a copy machine. We place a picture or document over the glass and, using software, we can copy that image into the computer.
This sounds simple, but creating good quality scans, especially from older photographs, can be a complicated process. Many aging photos are dirty or cracked, with missing corners. Some may even be ripped to pieces. Here are some things to keep in mind, and some tips for scanning your own images.
Types of Scanners
There are two main types of scanners on the consumer market today. Flatbed scanners, and document scanners. Several all-in-one machines include printers and fax machines, but they will still fall into one of these two categories.
Flatbed Scanners – These scanners have a lid that opens, and the image stays still while the scanner is working. However, if the image is larger than the scanning area, it can make scanning difficult. Many of these types of scanners also include adapters that will scan film or slides.
Document Scanners – Document scanners automatically feed your image through a series of rollers and scan it on the way through. These scanners have width restrictions, but can scan much longer documents than a flatbed can.
There are other types of scanners, including dedicated film scanners, and drum scanners, but since these are usually used by photography and design professionals, we will focus on the 2 common consumer types today.
CCD vs. CIS
Scanners can use two types of technology to create the image: CCD (Charged Coupled Device), and CIS (Contact Image Sensor). These two technologies can both be found in consumer level scanners, with the CIS devices being cheaper, as they contain less complex components. Both technologies are useful, however there is one specific instance where the CCD scanner is essential: book scanning.
When scanning a book, you generally open it and lay it flat on the scanner bed. This means that as the page gets closer to the binding, it will lose contact with the glass. A CCD scanner will still be able to scan the part of the page that isn’t touching the glass, but since a CIS scanner requires contact with the scanner glass in order to scan properly, the part of the page nearest the binding will be blurred out.
Other than this specific instance, both technologies should be acceptable for home use. For more information about CCD vs CIS scanners, check out this 2007 article from EEPublishers.co.za.
Buying a Scanner
When looking for a scanner for potentially damaged images, there are a few things we want to keep in mind.
For older images, always use a flatbed scanner. Never use document style scanners for a damaged image. These scanners are fine for documents, but older, delicate images can be torn apart in these sorts of scanners.
Also, many consumer level scanners include the ability to scan photo negatives easily. It is always worth an attempt to scan the original negatives if they are available, so this feature is a big plus.
Most consumer level standalone scanners can be had for under 100 dollars in many electronic stores. However, the industry has shifted away from standalone scanners to the all-in-one devices. Many times, a brick and mortar store will only have the all-in-one devices, and you will have search an online retailer for a standalone scanner. In many cases, you can get a higher quality scanner by purchasing a standalone scanner, but if you also need a printer, the attached scanner is usually of good quality.
Scanner technology has advanced to the point that many of the cheapest models will do simple image scanning without problems. Just make sure that your scanner can scan images at least 300 dpi (it’s likely that you will have a hard time finding a scanner that can do less), and will scan full color images. Also ensure that the scanning area is at least 8 1/2 x 11 inches.
The Scanning Process
Once you have selected your scanner, here are some steps you need to complete to get a good scan:
- Clean the image -When scanning an image of poor quality, always attempt to correct as many of the problems as possible before putting them into the scanner. Clean the image with a dry cloth or compressed air to remove dust, make sure that any pieces that have been folded underneath the image are visible, and so on.
- Clean the Scanner – Second, before you begin, make sure that the glass of the scanner is clean. Follow the cleaning instructions included with your scanner and only use a cleaning solution recommended by your scanner manufacturer. Make sure that it is dry before placing the image on the glass.
- Place the image carefully – While Photoshop can align images, the best practice is to align the images on the scanner bed. Many scanners have guides around the glass to show where certain page sizes can fit easily.
- Preview the Image – Once you open your scanning software, you will likely see a Preview button and a Scan button. Clicking the Preview button will quickly scan the glass, so that you can see if the image is aligned properly and if the glass is clean.
- Select the Image – Most scanner software will attempt to recognize where the image is and select it for you. You can always re-select it yourself if the software didn’t recognize the image properly.
- Set the Resolution – When we scan an image, we want to start with as many pixels as possible. You might have to switch to the advanced options, but you should be able to set the resolution for your scan. 300 dpi (dots per inch) should be considered the absolute minimum. Higher dpi means a slower scan, but a higher quality image, and many times, when doing healing corrections, the more pixels we can get the better. Just remember to reduce the number of pixels in the Image Size dialog box once the project is complete.
- Set the options – Scanner software generally attempts light image retouching through the advanced features. While these are useful for users who either don’t have access to or experience with Photoshop, doing these corrections in Photoshop will generally lead to better results. However, if a quick touchup is desired, these automatic tools generally suffice.
- Scan – The final step is to click the Scan button and allow the image to be scanned into the computer. This will generally be a short process, and once it is done the scanner software will either open the image in an image editing program or save the file, depending on the software. From there, you will be able to edit it like any other image.
Scanning can be very simple, but having a little know-how will increase the quality of your results considerably.
