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Scanning & Digital Imaging in a Nutshell: An introduction to scanning and digital photography

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Digital Photography and scanning can be complicated subjects. If you're like most of us you have some knowledge of digital imaging but aren't an expert. Please read on to learn some basics.

What is a digital photo?
Digital Photos are a grid of "Pixels," or (picture elements). Most digital photos are made up of millions of these pixels. Pixels are tiny sections of color or tone that together form a photograph. Each pixel is made up of 3 values; red, green, and blue, or RGB. This RGB information is used to determine the color of each pixel. In a 24 bit color image each of these RGB values is made up of 8 bits; 8 bits for red, 8 bits for blue, and 8 bits for green, for a total of 24 bits. Each 8 bit value has 256 possibilities ranging from 0 to 255. So to make a purple pixel you would combine some red with some blue, just like mixing paint. The RGB data for this purple pixel might be like this (red=255 green=0 and blue=220). A digital photo is simply lots of pixels stored in a grid. This grid and it's pixels are the basic components of any digital image. Typically, photos are saved as JPEG or TIFF files. These files simply contain the grid and RGB values for all the pixels in the image. If you zoom in far enough you'll be able to see individual pixels in any digital image.

How do scanners work? and what is resolution?
Scanners simply read color information from a photograph or piece of film and record this information as a grid of pixels. The amount of detail captured with a scanner is determined by something called scanning resolution. Resolution is measured in samples per inch or SPI. Many times people refer to resolution with the term DPI, "dots per inch", or with PPI, "pixels per inch". SPI, DPI, and PPI all describe the same thing. For simplicities sake we'll use the term DPI from here on. So what does "dots per inch" mean? DPI means that a scanner will capture so many dots or pixels for every inch of area scanned. For Example: If you were to scan a 5x7 photograph at 300 DPI you would end up with a digital image that is 1500 pixels wide and 2100 pixels in height. Some simple arithmetic was used to arrive with these numbers. The photo being scanned was 5 inches wide and 7 inches tall. The photo was scanned at 300 DPI "dots per inch". Simply multiply the resolution, 300 in this case, by the dimensions of the photo being scanned, 5 x 300 = 1500 and 7 x 300 = 2100. Resolution determines how much information a scanner captures from the photograph of film being scanned. The higher the resolution, the more pixels the resulting digital image will contain. The more pixels an image contains, the more detailed the digital image is.

What does Megapixels mean?
Most of us have heard the term Megapixels. Today digital cameras are rated by a term called Megapixels. Megapixel means 1 million pixels. In the example above we determined that a 5x7 print scanned at 300 DPI creates a digital image that is 1500 pixels wide and 2100 pixels high. If we multiply the width by the height we can determine the number of pixels this image would contain. 1500 x 2100 = 3,150,000. So the image in this example would contain 3,150,000 pixels. Or would be just over 3 Megapixels.

Is higher resolution better?
Higher scanning resolutions will definitely capture more detail during scanning but the highest resolution possible is not always the best way to go. To determine the best resolution for scanning you must consider what is being scanned. Ideally we want to capture every detail contained in a photograph or piece of film. However modern scanning equipment can capture more detail than some films or prints contain. Scanning beyond the detail contained in a given image only ads more data without any extra detail.
Prints typically contain no more than 600 DPI worth of detail so scanning at higher resolutions is not necessary. However slides and negatives contain much more detail per square inch and thus need to be scanned at much higher resolution than prints. The amount of detail a slide or negative contains varies with film type and film speed.

What resolution will I need?
To determine what resolution you will need you should first consider what you wish to do with your digital images. If you wish to view them on a computer or wish to e-mail them to friends and family, your needs will be different than someone who wants to create 11x14 prints from a digital image. Please click here for help with resolving your resolution needs.

What Next?
This page is meant as an introduction to digital imaging. Don't worry if some of the things here are a little confusing. Our "Scanning Needs & Resolution" page will help you assess your needs and determine which service will be best suited to your needs. To visit this page click here.

Scanning Services: Slide & negative scans come in three varieties; Silver scanning, Gold scanning, and Pro scanning. Print and photo scans come in two flavors; Silver photo scanning, and Gold scanning. Click a link to learn more about our scanning services.
Slide & Negative Scan Comparison | Photo Scan Comparison

Digital Image Benefits: This article outlines the many benefits of digital photography.

An Introduction to Digital Photography: This article explains digital images, Resolution, and Megapixels. It provides a brief technical background to digital imaging.

Scan Resolution Help: This article explains scan resolution. It looks at scanning resolution from three perspectives and makes recommendations accordingly.

Photo Scans vs. Slide & Negative Scanning: This article compares photo scans with slide & negative scans. It also outlines the limitations of photo scanning.

JPEG vs. TIFF File Format:
This article briefly discusses these two unique file formats.

CD vs. DVD:
Wondering what a Data DVD is? This page explains Data DVDs and compares them with CD-Rom for storage and backup of digital photos.

Disk Organization:
This page explains how your disks will be organized after scanning.

You may also find our order planning guide helpful.

Got Questions? Contact Us 1-800-383-2903