Frequently Asked Questions
Q: What is a scanner?
A: A scanner is a device that analyzes a flat object or 3D object and turns it into a digital image file. It uses light reflected off of an object to a CCD or CIS which converts the signal into a digital bitmap image.
Q: What is PPM?
A: PPM is an abbreviation for pages per minute, or how many pages a scanner can process in 60 seconds. Flatbeds typically have the lowest PPM, production scanners the highest, with mid-range sheetfed scanners, predictably, somewhere in between.
Q: What is DPI?
A: DPI, or dots per inch, is a measurement of scanner resolution. Most scanners have a resolution of at least 300 x 300 dpi. Higher resolutions are usually software enhanced or interpolated, meaning extra pixels are added between the pixels that are actually scanned to increase the perceived resolution.
Q: What is bit depth?
A: Bit depth refers to the number of colors that a scanner can reproduce, in color and in grayscale. Most scanners support at least 24-bit color for photos, images, and color graphics. Some offer a higher dpi, like 36-bit, 42-bit or 48-bit color. For grayscale, most scanners typically support 8-bit or 16-bit.
Q: Are higher bit scanners better?
A: There are 24-bit, 30-bit and 36-bit scanners, which is better? 24-bit scanners produce 24-bit scans. 24-bit scans will give everything you're looking for in a scan, but if you brighten the image file, you lose some of the mid-tones and shadow detail. 30-bit and 36-bit scanners produce 24-bit scans. Confused yet? The scans produced by the 30- and 36-bit scanners drop 2 to 4 bits of unneeded information to make for a better image, preserving the look of the original.
Q: CCD? CIS? What's the difference?
A: CCD is now the standard device used in today's scanners. It stands for Charge Coupled Device and it works like this: The device accepts light, converts it to electrical chargers that are then stored and manipulated into digital images. CIS on the other hand used to be the standard, but it has been mostly replaced by CCD. CIS based scanners are heavier and slower than their CCD brethren.
Q: What kind of scanner do I need?
A: The kind of scanner you need depends on what you'll be using the scanner for. Flatbed scanners will generally give you all the function you need for home use and are the most affordable. Sheetfed scanners are good for small to medium offices that do a moderate amount of scanning. Production scanners are the most expensive, but also offer the highest performance and a wealth of features. They can scan 10-150+ pages per minute and are capable of handling hefty scanning jobs on a daily basis.
Q: What is a flatbed scanner?
A: A flatbed scanner, sometimes called a desktop or photo scanner, is the most common type of scanner for home or small office use. They're versatile, generally inexpensive, and great for lightweight scanning jobs, like bills and documents or for creating digital photos and records.
Q: What is a sheetfed scanner?
A: Sheetfed scanners look like small printers and operate similarly to flatbeds, except the document is fed through the device while the scan head is immobile. Some may require the user to manually feed the documents one at a time. Others have automatic document feeders. Some sheetfed scanners also offer flatbed scanning for added flexibility.
Q: Can I scan more than just documents and photos?
A: Yes, a number of scanners also have the capability to scan film, slides, negatives, transparencies, business cards, and other items. Make sure you check the detailed specifications and features to see what kinds of media a scanner can accommodate.
Q: What is optical resolution?
A: Optical resolution refers to the number of pixels or dots per inch (dpi or ppi). A greater number of pixels results in sharper image quality. Resolution is typically quoted vertically and horizontally. (300 x 300, 2400 x 1200, etc.) If you want to scan detailed images accurately, accept no less than a 1200 x 1200 optical resolution rating.
Q: What is interpolated resolution?
A: Interpolated resolution is determined by the scanner adding pixels in between existing pixels using a mathematical formula to accurately improve resolution based on the existing pixels. This isn't always the best indicator of image quality, better to rely on the stated optical resolution.
Q: What is optical density?
A: This is a measure of how well the scanner can capture the tonal range of an image. Optical Density is measured on a 0-4 scale, with the number representing the the difference between the darkest and brightest optical densities a scanner can capture. Most scanners carry an optical density measure of 2.7-3.1, this is fine unless you plan on scanning slides, transparencies or negatives, which will require an optical density of at lease 3.2.
Q: Does my choice of software matter?
A: The simple answer....YES. Your scanner is only as good as the drivers and software that run it. It's important to invest in a scanner that is bundled with utilities and drivers that are compatible with your system, as well as software that allows you to manipulate scanned images effectively.
Q: How does a scanner connect to my computer?
A: Most scanners on the market connect through either a Hi-Speed USB cord or SCSI port. Some models connect through FireWire or a parallel port, respectively the fastest and slowest transfer methods.
Q: Can I attach my scanner to a network?
A:This isn't very practical for a multitude of reasons. The main reason is that scanners can only perform one function at a time anyway. In addition, additional users would have to walk back and forth to the scanner, annoying not only them but the user who's PC is actually attached to the scanner itself. It's a better idea to purchase a dedicated scanner for each person who will need them frequently. That being said, HP offers some high end scanners that come equipped with an integrated network card.
Q: What does a scan imprinter do?
A: An imprinter, whether it's included in your scanner or bought as an accessory, helps you keep track of scanned documents, which makes it ideal for offices that scan a large number of important items. The imprinter provides a unique number or alpha-numeric code to each document scanned, printing the code on either the front or back of the document. Imprinters come in pre-scan or post-scan models.
Q: Do I need a transparent media adapter?
A: If you need to scan film and have no other options for getting your images to digital formats, then it's a good idea to spring for the TMA (transparent media adapter). This will allow you to more quickly digitize your film, without having to first process the pictures. The TMA works by using a lamp above the film, projecting the image onto the scanner, instead of using the main light located below the glass.
Q: Do I need to buy a scanner from the same brand as my computer or printer?
A: The majority of scanners on the market are both PC and Mac compatible, so you can select the one that best suits your needs and budget without worrying whether it will work with your computer. Scanners also come with software to help you install and use your model easily.
Q: What if I need to replace the lamp in my scanner?
A: Eventually, you will have to replace the lamp in your scanner. This can be postponed by making sure to turn off the lamp anytime you aren't actively using your scanner. SuperWarehouse offers a complete line of replacement bulbs for scanners. Simply call one of our Product Specialists at (800) 814-5410 for assistance.
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