File Formats: A Review

Hi guys!
I’ve noticed some of you have been confused about file formats in class and thought we’d review some Post-Production basics.

File Formats Explained

JPEG | These images are a standard for web and email images as well as images from compact digital cameras.Additionally, they work well for consumer end images that don’t require a great amount of detail.

Be aware that JPEG compression quality loss is cumulative, meaning that if you open a JPEG image and edit it (crop, change color, resize, etc.) and resave it as a JPEG image quality will be lost. It is a good idea not to repeatedly save as a JPEG.

TIFF | These images are a standard for large-format printing and high detail. A TIFF image is an uncompressed image showing the full detail of the image with no quality loss. TIFF images are large and can take up more storage space and a longer time to save to the memory card.

TIFF FILE FORMAT. TIFF stands for “Tagged Image File Format” and is the format of choice for archiving important images. TIFF is a leading commercial and professional image standard. TIFF is the most universal and most widely supported format across all platforms, Mac and Windows. TIFF files are significantly larger than their JPEG counterparts, and can be either uncompressed or compressed using lossless compression for compatibility (8 or 16 bit.)

RAW | A RAW image is the pure data directly saved from the camera’s image sensor onto the card. With other image formats the camera processes the raw data and converts it to TIFF or JPEG, but with RAW mode the pure data is saved and can be edited later. Since no corrections have been made, there is more opportunity to edit the file later. RAW images must be converted to a printable format (like TIFF) using proprietary software. Think of RAW files as the closest thing to a digital negative.

As far as quality and versatility goes, nothing beats a RAW file. RAW files contain the most information (like capturing 4096 shades of gray instead of only 256) and allow for the most versatility when it comes time to open your image in Photoshop. With the advent of non-destructive editing and metadata, this format is the best choice. You can always save down, but you can never recover information you never captured. But having said that, RAW files also take the most work to get a great-looking image.

Compression Explained

  • Lossless compression compresses an image so when it is uncompressed, as it is when you open it, its image quality matches the original source—nothing is lost. Although lossless compression sounds ideal, it doesn’t provide much compression so files remain quite large. For this reason, lossless compression is only used by the highest quality image formats—namely TIFF and RAW.
  • Lossy compression (rhymes with “bossy”) can dramatically reduce file sizes. However, this process degrades images to some degree and the more they’re compressed, the more degraded they become. In many situations, such as posting images on the Web or making small to medium sized prints, the image degradation isn’t obvious. However, if you enlarge an image enough, it will show. The most common lossy file format is JPEG and many cameras let you specify how much they are compressed. For example, many cameras let you choose Fine (1:4), Normal (1:8), and Basic (1:16) compression. This is a useful feature because there is a trade-off between compression and image quality. Less compression gives you better images so you can make larger prints, but you can’t store as many images.


So which file type is right for your work?

While it’s always best to shoot in RAW when you can, if you need to take multiple images at a time and are pressed for file space, a JPEG is a fine option. If you are not concerned with detail in a large-format print, a high resolution JPEG should work in most cases—especially for consumer end use or image-heavy print publications.

Yet, if you are shooting in RAW and want to preserve much of that detail, retouching your images in Photoshop for high-end printing, a TIFF might be a better choice. Many fine art printers use TIFF as their preferred standard for its lossless capability and fluid compatibility.

Some additional references:
Image Loss Tutorial
Lynda: Comparing RAW, JPEG and TIFF files
More about File Formats



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