File Formats

Understanding file formats is a very important part of working in the digital world. There are hundreds of format combinations, with many flavors and choices within each of the formats. The formats you choose to input, work on, archive, and output will affect the quality of your final image as well as determine whether or not you'll be able to use the image for future applications. If you save a file using a format that compresses the image data, some data is lost and can never be recovered.

When you are scanning from slides this isn't as much of an issue, because film can be re-scanned. But if your image is coming from a digital camera, you will not have another chance to get back quality in an image, once you have stored that file in the incorrect format (unless of course, you keep all of your originals). Even if your image is captured on film, there is a chance the film can become damaged or discolored over time and you may not have another chance to capture the image digitally once this happens. Your best bet is to scan the slide and archive it digitally in the correct file format.

The reason we need so many different file formats is because the same image can go in so many different output directions. You'll need JPG or GIF for web sites, TIF for print, PSD as a Photoshop work file, and even more choices when you're moving files across different computer platforms. Many of the formats were developed years ago for special purposes, such as PCT and BMP, but have stuck around with little purpose but to complicate and confuse the digital artists.

It is important to understand which formats are used for what purposes. This is why we've divided this section into source, working, archival, and output formats.

A critical catch phrase to remember through this section is "garbage in, garbage out".

Always capture the images at the highest quality and the lowest compression that your camera will allow. This will mean that the number of images you can fit onto a single storage medium will be limited, but at least the images you capture will be the best they can be. By doing so, you are bringing in the image at the highest quality possible, leaving your work and output options open.

In the example to the right a file was saved in a number of different formats. The original slide was scanned at 5503 x 3597 pixels and the file size was 56.6 Mb when opened in Adobe Photoshop. You can see which of the formats compress the file, since the file sizes are much smaller. Although you can get a lot more images onto a CD ROM when you archive the images using compression, you're also destroying the integrity of the image, in some cases to where the image would not even be usable again for most applications. The file fishL.jpg was saved using JPEG highest compression, rendering lowest quality. Notice the file is only 600 K in size, but when you open that file, you'll be lucky if you can use it for anything.