This is the third post in a set of four which outline the nature of images, formats and applications.

As the complexity of digital images has grown, new formats have appeared to enable these capabilities. In fact, formats have always largely been purpose-driven. They are created as standardized containers that facilitate saving particular types of data, usually in service of some particular workflow. Sometimes formats are designed as general purpose containers, and sometimes they are highly purpose-driven. 

Let’s look at the evolution of formats in light of the purposes they serve in the digital photography environment. 

Interchangeable formats

The Compuserve GIF format was introduced in the late 1980s and became one of the most useful formats for image interchange between computer systems and programs. This was followed by the TIFF and JPEG standards in the 1990s. 

Highly efficient image storage

The JPEG standard was created to enable high quality images to be saved and stored with full color and an efficient compression scheme. It became a hugely successful standard. 

High quality image storage

Other applications were more oriented to the creation of a standard format that could store images with the highest quality possible. TIFF was created for this purpose.

Consistent color

In the1990s, the International Color Consortium (ICC) organization created a method to standardize the way to encode and decode color, and to convert color for consistent appearance on different devices. This capability was added to JPEG through the official standard, and added to TIFF by unofficial consensus. 

Multi-part master file storage

As images became dependent on multiple embedded files, masks, alpha channels and other components, it became commonplace to store as many of the components in a file as possible. Adobe has specified the methods to do this in the  PSD format specification, and these methods have generally been adopted into TIFF usage, even though they are not an official part of the TIFF standard. 

Digital camera originals

Digital camera raw images introduced the need for a dedicated file type that could support the encoding these files required. Raw image data is encoded very differently than “standard” image data. The TIFF/EP format was designed for this use, and some formats like the Nikon NEF are quite similar, and some take a more independent approach. 

Digital camera master files

Digital cameras led to a wide variety of approaches to file encoding and structure, with many of them undocumented. The DNG format was created to bring standardization to raw image storage. Not only does it allow for the standardized storage of camera original information, DNG also provides a way to store items that are useful for good post-production workflow. 

Mobile/Cloud native capabilities

Taking a clue from the capabilities of DNG, the HEIF format provides a flexible storage container that can accommodate the storage of multiple versions of an image, depth data, and even alternate versions that are created for particular uses. DNG was also updated to include some cloud workflow components, particularly the use of proxy files. 

Most of the advances in images and formats became necessary as the capabilities of hardware and software have evolved. In the next post, we will examine how applications have evolved along the same timeline.

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