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PHOTOGRAPHIC FILE FORMATS
What Is With All These File Formats?

Gerry Stoner

There are many file formats used in digital graphics, but I recommend you work with the best two traditional file formats: TIF and JPG.

Objective: To familiarize yourself with the uses, benefits, and conversion of TIF and JPG.

File formats
There are two file formats that you will use when working with digital images:

• TIF (TIF, .tiff, or .tif) is the standard format of the printing industry.
• JPG (JPEG, .jpg, or .jpeg) is the standard from the electronics industries.
  

File integrity and compression algorithms
Because picture files are large, graphic formats offer built-in compression, making smaller files by discarding some information. The greater the compression, the more information is discarded. Compression algorithms are called "lossy" to indicate this loss of file information.

• TIF compression is called LZW, but its use is optional and should never be used. Without LZW, TIF files are lossless.
  Make sure that you keep LZW turned off in the Save As window.
• JPG compression ratios can be modified but not completely turned off. For this reason, JPEG is a lossy format.
  Make sure that your save as preference is for minimal compression.

File modifications
When working with a picture file, you may need to save it several times before it is ready for its final purpose. To avoid needless compression and lossy saves, you should always use the TIF format for initial scanning, all intermediate steps, and final review.
        Use JPG only at the final Save As step when the JPG format is required.

Formats for various end uses

• TIF should always be used in a file for printing on paper, with one exception:
  machines to make photographic copies use JPG files, so your final save as should convert the file to a JPG.
  
• JPG should be used when the final file will be uploaded to the Internet or embedded in a file for use on a monitor.
  

This article is one of several to help you document local history. Other articles will help you convert your interviews, documents, pictures, and artifacts into documentation of your local history that can be shared with your community.

Assignment: Most historical societies close down for the winter, and non-migratory neighbors tend to fight cabin fever by going to the Saturday or Sunday afternoon movies in Hunter, at the Power Authority, or another venue. While these may be fun, I hope you set up this alternative: host a series of workshops using this article as a focus and start to document your own local history.

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