With conventional scanning, it has always been important to know exactly what you plan to use your digital images for before requesting a scan. We can provide scans that are perfect for web publishing and on-screen Powerpoint presentations to high-end, four-color printing and everything in between.

We offer custom scans from our Scitex EverSmart Pro scanner. For your less demanding scanning requirements, we offer our Fuji Photo Disc, Production and Economy scans.

No matter how your images are digitized it is very beneficial to know how to determine the optimum amount of pixel information required for your project.

The following sections are here to help with the tough issues that face you, the digital practitioner, in your quest for the perfect scan.

FACTORS TO CONSIDER WHEN ORDERING A SCAN

To help you choose the best option for your job, you will need to consider:

	What size is your photograph or artwork?
	What level of quality is required for your project?
	What size scans do you need to successfully complete your project?

What size is your photograph or artwork?

Your images can be in many forms. At Chrome we have scanners to scan the following:

Negatives, Slides, Transparencies and Flat Art up 12 x 17 inches.

What level of quality is required for your project?

There are several factors that determine the quality of scans. The original image being scanned should be of excellent quality and condition, and employing a highly-trained scanning technician ensures that the equipment produces the best possible result. But there is also a wide range of quality in scanners, and factors such as dynamic range, color depth, sharpness and resolution capabilities separate a mediocre from a top-of-the-line scan. CHROME offers the following types of scans to satisfy a wide range of applications.

Custom Scanning - When you need the best dynamic range for output to our high-quality printers and film recorders, or for pre-press and commercial printing applications, you may decide to choose one of our custom scans. We can provide you with custom scans from our Scitex Eversmart Pro, capable of 8200 ppi maximum resolution, 42 bit color depth and 4.0 maximum density. This scanner can scan slides, negatives and flat art up to 12x17 inches.

Production Scans - These scans are ideal for 35mm and 120/220 film images that may be used for larger prints, such as 5x7s, 8x12s and 10x15s. They are produced on our Fuji Frontier system and are optimized for print output on that system, but these scans can be used for other various projects. Choose these scans if you are a retoucher or want to archive your images at resolutions that can support larger prints.

Fuji Photo Disc and Economy Scans produced on our Fuji Frontier system can inexpensively scan your 35mm negatives and slides onto a CD that can be used with your home PC or Macintosh computer. The JPEG files easily attach to email, so you can share your images with family and friends! You can even reprint your snapshots on your home ink-jet printer. Have your rolls of film scanned when you bring them in for processing at CHROME.

What size scans do you need to successfully complete your project?

A very important factor to consider when requesting a scan is what you will be doing with that scan. Requesting a scan that is too large can needlessly bog down your system, take up your valuable storage space and cost more money. On the other hand, a scan that does not contain enough pixel data for your project can produce unsatisfactory results. For some instructions on determining how large a file will best suit your needs, please see the How to Compute the File Size of Your Scan area below.

HOW TO COMPUTE THE FILE SIZE OF YOUR SCAN

Information to know before you start:

1. Final use of your scanned image

Some examples:

	4-color Printing
	Digital Prints
	Screen Viewing (web pages, on-screen presentations)

2. Resolution of the output device you will be using to produce your finished image

Examples:

	Line Screen (LPI in 4-color printing)
	Dots Per Inch (DPI)
	Pixels Per Inch (PPI - screen presentations, Web pages)

3. Final dimensions (in inches) of your image

Scans are expressed in pixels which is the smallest element of a digital image. The number of pixels in the scan determine the resulting file size.

Your specific output device determines how those pixels are distributed on paper, film or computer monitor. For example, when scanning for output to continuous-tone digital printers, such as our Fuji Frontier system, it is advisable to scan the image so that you capture enough pixels to print one digital pixel to each 'dot' that the printer prints to paper. If you plan to print an image that is 3 inches x 2 inches with a resolution of 300 dots per inch, you would obtain your optimum print with a scan that is 900 pixels x 600 pixels.

Other types of digital output, such as laser printers and digital pre-press separations, use a half-tone screen to define an image. You can ask the service bureau or refer to the printer documentation to determine the screen for a specific printer. With this information, you can determine your scanning resolution using the following information:

Finding the file size of your scanned image

Once you know how much digital information you need to best meet your needs, it is easy to roughly calculate the size of the resulting file. Here's how:

1. First calculate the total number of pixels that will be needed for your scan:

Example:

Resolution x Width = Pixel Width Resolution x Height = Pixel Height Pixel Width x Pixel Height = Total Pixels required
300 x 3 inches = 900 pixels 300 x 2 inches = 600 pixels 900 x 600 pixels = 540,000 pixels

 

2. Next determine the bit-depth of the scan you need.

There are three types of scans that we can do at Chrome.

	Line art (1-bit, all pixels either pure black or pure white - Customs scans only)
	Grayscale (8-bit, 256 levels of gray)
	RGB color (24-bit, Red, Green & Blue channels, each capable of 256 possible intensity values)

Line art scans are used when scanning text or camera-ready art.

3. Finally, use the following formula to calculate the file size (Find Total Pixels by method described above):

Example:

A 2 inch x 3 inch image being scanned for a 300-dpi continuous-tone output would require the following file sizes:

Line Art: 540,000 pixels ÷ 8 = 67,500 bytes or 67.5 kilobytes (67.5 KB)
Grayscale: 540,000 pixels * 1 = 540,000 bytes or 540KB
RGB Color: 540,000 pixels * 3 = 1,620,000 bytes or 1.62 megabytes (1.62 MB)

 

The concept of pixel resolution can be less confusing if you understand the following example: Please observe that 2000 x 3000 pixels is the same amount of digital information whether it is expressed as: 27.8"x41.7" at 72 pixels per inch or 6.7" x 10" at 300 pixels per inch or any other resolution you choose to distribute those 2000 x 3000 pixels. Opening your image in the Photoshop Image Size dialog box and changing the resolution does not add or subtract any digital information and does not alter the quality of your image in any way (provided that you constrain the file size and avoid "resampling" the image). If you change the resolution of your image while keeping the file size the same, you are simply instructing your software to either spread your pixels farther apart, or pack them together more.ightly - you're changing the number of pixels per inch. You'll notice that the image width and height changes in response to your resolution adjustments. The ideal setting depends entirely on the output device you will be using, whether it is a printer, film recorder, monitor screen, etc., and the final size of your image being output by that device. For best results, do not "resample" your image (change the file size by adding or subtracting pixels) any more.han necessary. This does degrade the quality of the image. It is best to output at a size and resolution that most closely matches the original size of your image. Keep an eye on the file size at the top of the dialog box, next to "Pixel Dimensions", which shows the new file size and the what the file size "was". Generally, it is much better to resample an image to a smaller file size than to increase it to a larger file size, but starting out with the proper resolution when the image is captured (scanned, rendered, etc.) is best.

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