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Scans, Scanning and Digital Files.

 

What is a digital image file?

A digital image file is a file used by a computer to recognize, display and use an image. Your computer may have more than one program capable of interpreting and displaying digital image files. Adobe Photoshop is the most widely utilized program in the graphics, photographic and printing industry used to display, adjust and save digital image files.

Where do digital image files come from?

Digital image files can be produced from a photograph or a piece of artwork using a scanner or created directly with a digital camera.

What is a scan?

A scan is a digital image file produced by a scanner from photographic film or artwork. A scanner detects the varying amounts of red, green and blue (RGB) light transmitted through or reflected from the photograph or artwork and records that information as a digital file. Your computer then reads that information and tells your computer monitor to display those amounts of red, green and blue light to create an image on your monitor.

When a printing company scans your photographs they also convert the RGB colors into cyan, magenta, yellow and black (CMYK). These four colors relate to the four printing inks used in a traditional printing press. The conversion from RGB to CMYK usually occurs "on the fly" or during the scanning process. For more information about CMYK files and printing color click here.

A computer can display images in both RGB and CMYK format. Desktop printers print RGB files and all images used on the internet are usually RGB files. CMYK files are used in traditional printing press work.

What is the difference between a scan and a digital file made by a digital camera?

A digital camera records the red, green and blue light striking the sensor and records that as a digital image file. A camera using film does a similar job but the record of the light is stored by a piece of film using dyes.

In order for a computer to use a photograph captured on film the information on the film must be converted into a digital record via the scanning process. A digital camera skips the film and scanning steps, creating a digital file directly from the light striking the camera's sensor.

What are the advantages of film vs digital image capture?

Film:

Pros: Film produces a photograph with many more colors than a digital camera can capture. You also do not need a computer or other piece of hardware to view a photograph.

Cons: Film is expensive to produce. It also needs to be scanned in order to be used on a computer and printing press which takes time, costs money, reduces the sharpness of the image as it passes through another optical process and reduces the number of colors down to the same (or similar) as a digital camera. Film images contain "grain" which can be visible when enlarged.

Digital Camera:

Pros: A digital file does not need to be scanned in order to be used in the printing process therefore does not suffer loss of sharpness or detail that is inherent in converting an image from film into a digital file. After the initial purchase of the camera, ongoing images cost almost nothing to produce. Images can be viewed, transmitted and used immediately. No grain.

Cons: Digital cameras currently produce files much smaller than those that can be made via the film scanning process.

 

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