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Scanning Tips

Determining the Correct Amount of Resolution

  • More is not always best. Determine what your final application will be BEFORE you scan. In many cases a high resolution image will do nothing more but dramatically increase the file size, take up more disk space, and slow down the process.
  • Internet Applications: For e-mailing color photos or pasting images on websites, a resolution of 75 dpi is the best choice. This is because the actual viewable resolution of the average monitor is 72 dpi.
  • Printing to Ink Jet Printers: Check your printer documentation for recommended printer resolution settings. We recommend ranges between 75-300 dpi in general. Only use a higher scanning resolution (301 dpi and above) for smaller images when detail must be captured in a small area because it will be enlarged later.
  • Laser and Commercial Printers: When printing an image to a laser printer or commercial printing press, it is important to understand the process in terms of line screen (a.k.a., LPI). Line screens are the number of screen lines per inch when an image is halftoned. Halftoning is the process of breaking the image down into a series of dots to reproduce continuous-tone art when printing on a press. A general rule when printing in one of these two manners is to scan one and a half to two-times the amount of the line screen. Laser printers that have resolution ranges of 300 and 600 dpi will have line screens between 50 and 100. Typical commercial printing is done at an average line screen of about 150. Therefore, an optimal scanning resolution would be from 225 to 300 dpi.
Scanning Tip: Monitor Gamma

Adjusting the monitor gamma is a critical step to ensure that you view your images properly. To adjust your monitor's gamma, please perform the following steps:

  1. Choose the monitor gamma option by selecting SETUP under the file menu and clicking MONITOR.
  2. Select the MONITOR GAMMA option.
  3. Drag the slider bars until the hue inside each rectangle is the same color as their adjacent colors. When finished, click OK to exit. Note: The steps for adjusting your monitor gamma may vary dependent on the application.

For Additional Help

Under the HELP menu, click HELP. This directory lists complete information about all of your image-editing program's basic and advanced functions. Use it to guide you through any questions you may have.

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Buying Scanner Tips

How to Buy a Scanner

The first step in purchasing a scanner is to think in terms of what your needs are as well as your budget. Will you be purchasing a scanner primarily for e-mailing pictures and/or creating web sites? Or perhaps you are interested in a scanner that will allow you to perform various faxing or copying functions. Dependent on your needs, certain models may be more attractive based on their features and specifications. It is important to understand those features and specifications clearly to help you make the best purchasing decision.

How Much Resolution Do I Need?

The resolution specification is the first specification that most people are interested in, however it is also one of the most misunderstood specifications. Resolution is expressed in terms of dots-per-inch (dpi) and determines the overall detail of an image. There are other terms such as optical resolution and interpolated resolution that should be addressed.

Optical resolution can be thought of as the scanner's "true" resolution. This figure is determined by the amount of scanning pixels on the scanner's CCD (the light sensor that captures the image) divided by the scanning area of the image. For example, a CCD that contains approximately 2,550 pixels divided by the horizontal scanning area of a typical scanner (8.5"), equals 300 dpi.

Interpolated resolution is added resolution that is created by the software of the scanner itself. Basically, a 300 dpi image can be further broken apart as additional dots are added. These additional dots take the averages of the nearest pixels to selectively determine the proper color values. Interpolation can have a softening or smoothing effect, but will also increase the physical file size of the image dramatically.

When shopping for a scanner, the important figure is the scanner's optical resolution. Another issue of course is to understand how much resolution to use for each application. Many people will automatically assume that they need to always use the highest amount of resolution available for the best quality. This is not true. When scanning an image with a defect or flaw, the added resolution will only pronounce this flaw.

Resolution and file sizes of images are directly related. As you increase the scanner's resolution, the file size will also increase. For e-mailing an image or placing it on a website, it is important to not use too high of a resolution. The average viewable resolution on a typical monitor is 75 dpi, so it is unnecessary to scan at any greater dpi when displaying items on screen.

For printing to ink jets or color laser printers, you need not go beyond 300 dpi as the printer's available line screen figure (the amount of lines per inch available when an image is halftoned) will typically never move beyond 100 lpi. Halftoning and line screen are advanced concepts that are important to know and understand when printing at a commercial printing house, but are usually not significant for home. The rule of thumb is to scan an image at one and a half to two times the available line screen of your output device. Following this rule, you can see that 300 dpi is adequate.

So what is higher resolution such as 600 dpi used for? High resolution should only be used when scanning small images that you later want to increase in size in order to retain detail.

The Bit Depth Specification

The second significant specification that is examined is the bit depth figure. Scanners have progressed through various stages including 24-bit, 30-bit and now 36-bit. We typically think that the higher bit depth will provide greater value, however this is not true for everyone.

Mathematical formulas are used to determine how many colors a certain bit depth figure can capture. In theory, the numbers are impressive with 24-bit, 30-bit and 36-bit scanners each having the capability to capture 16.7 million, 1 billion, and 68 billion colors respectively.

There are other issues however that may lessen the importance of these figures. Some of the added bits in a scanner are used for alignment and filtering purposes to help clean up the signal so that in the end, the true colors captured are perhaps less than the numbers applied. Additionally, typical desktop computers are limited to viewing 24-bit images on screen due to the limitations of the video card and/or software.

In the end, the bit depth figure is more important for professional designers or those searching for the highest level of detail when printing commercially.

Bundled Software Package

Virtually all scanners on the market feature software to edit images and recognize text (OCR). Some time spent studying the software packages and their features will help you determine if they offer the added value that you are searching for with a scanner.

It is natural that higher end scanners will include software that is also considered high end. Keep in mind that high end might not always mean best. Consider the learning curves involved with many of the software applications available. For those people who want to do simple color corrections, there are various software packages available that will do these things simply and easily.

What Other Scanning Features Should I Look for?

Some scanners offer versatile features such as the ability to use the device as a fax sending machine or as copy machine. Other scanners allow you to scan slides and negatives as well as general documents and images. Some models also provide a parallel port interface that offers an easy, hassle-free installation as well as offering the ability to use the scanner with most portable notebook computers.

Some of these features, such as an included transparency adapter to scan slides and negatives may cost a bit more. For some, the added functionality of the scanner is worth it, for others not. Only you can truly determine what features you need the most.

Are you looking for a basic scanner for home use and simple projects. A 30-bit 300 dpi, parallel port model would probably be the best choice. Perhaps you are searching for a scanner that will serve as an office companion. Features such as the ability to scan legal size or larger may be an issue. You would also probably want the ability to fax or copy. Perhaps you are a graphic designer that needs many of the features a 36-bit scanner can offer. A model that not only offers 36-bit color depth and 600 dpi resolution, but includes a transparency adapter might be the ideal choice.

Scanner Image Sensors CCD and CIS

There are two primary image-capturing sensors used in flatbed and sheetfed scanners: the Charge Couple Device (CCD) and the Contact Image Sensor (CIS). The table below details some of their basic differences. What follows is a description as well as a comparison between the two image sensor type. For a detailed description of CCD and CIS, click here.

Signal to Noise Ratio Good Poor
Focal Length (distance between sensor and image scanned) Deep (Variable) Shallow (0 V 3mm)
Power Consumption High Low
Data Rate Fast (Averages 15 MHz) Slow (1 MHz)
Mechanical Layout Difficult Easy
Component Size Large Small
Image Quality Good Poor
Suited For Flatbed and moderately sized sheetfed scanners Sheetfed scanners
Depth of Field Deep (Variable) Shallow (+/- 0.5mm)
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Customer Service

If you encounter problems with your scanner, please go to our troubleshooting page.

For further assistance, visit our most frequently asked questions page. Or else, one of our Technical Support representatives will be happy to assist you from Monday through Friday 7:00 AM to 6:00 PM Pacific Standard Time.   To avoid any delays, please have the following information available before calling:

  • Scanner name and model number
  • Scanner serial number (located at rear of scanner near port connectors)
  • A detailed description of the problem
  • Your computer manufacturer and its model number
  • The speed of your CPU (Pentium 133, etc.)
  • Your current operating system and BIOS (optional)
  • Other interface cards in your system (including I/O address settings and IRQ settings)
  • Name of software package(s), version or release number and manufacturer of the software
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