Sustainability of Digital Formats: Planning for Library of Congress Collections
Sustainability of Digital Formats: Planning for Library of Congress Collections |
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| Introduction | Sustainability Factors | Content Categories | Format Descriptions | Contact | |
| Full name | Truevision TGA File format, version 1.0 |
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| Description |
A simple raster format for individual images first established by Truevision, Inc. in 1984. Designed for use on systems that used MS-DOS color applications, TGA is the native format of Truevision's TARGA (Truevision Advanced Raster Graphics Adapter) boards, which were some of the first graphic cards for IBM-compatible PCs to support truecolor display (most often defined as 24-bit RGB color encoding). TGA supports mapped/indexed color and RGB color, with additional support for transparency information (sometimes referred to as alpha channel, as in RGBA color space). Transparency information permits images to be superimposed over other data, e.g., additional images, text layouts, or video, and permits effects like cross-fading between graphic images and video, etc. TGA images may be encoded at 8, 16, 24, or 32 bits per pixel (as mapped/indexed color, RGB, or RGBA). TGA supported 24-bit color before such support was available in the TIFF format, and this helped establish the format's popularity during the 1980s. |
| Production phase | Most often an initial-state or middle-state format. |
| Relationship to other formats | |
| Has later version | TGA_2, Truevision TGA, version 2.0 |
| LC experience or existing holdings | The Library of Congress has a small number of TGA files in its collections. |
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| LC preference | See the Recommended Formats Statement for the Library of Congress format preferences for Still Image Works. |
| Disclosure | Proprietary. Truevision used to make the specification available. Truevision was acquired by Pinnacle Systems in 1999. The TGA specification does not seem to be available from the Pinnacle Systems website. |
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| Documentation |
The specification Truevision TGA, File Format Specification, Version 2.0 is available in various forms on the Internet, e.g.,
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| Adoption | This format was widely used by graphics specialists before most personal computers had graphics displays. As an industry standard, it is not as widely supported as PCX or TIFF formats. TGA (versions 1.0 and 2.0) have retained popularity for computer graphics professionals and video-game developers as a simple format that supports high bit-depth (up to 32 bits per pixel) and transparency. It is widely supported by high-end paint programs and ray tracing packages. Used in particular for "texture" files used for image composition and 3D-rendering techniques. |
| Licensing and patents | Technically proprietary, but not exploited. |
| Transparency | Licensing and patent claims |
| Self-documentation | Single image identification element of up to 255 characters. |
| External dependencies | None. |
| Technical protection considerations | None. |
| Still Image | |
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| Normal rendering | Good support. |
| Clarity (high image resolution) | Support for images with high spatial resolution. Support for RGB (plus transparency) color space or mapped (indexed) color and bit depth of 8, 16, 24, or 32 bits per pixel. |
| Color maintenance | Designed primarily for use on PC video displays using RGB colorspace. No support for ICC color profiles. |
| Support for vector graphics, including graphic effects and typography | No support for vector graphics. |
| Functionality beyond normal rendering | Support for transparency. |
| Tag | Value | Note |
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| Filename extension | tga |
Recommended in TGA version 2 specification. |
| Filename extension | vda icb vst |
Used in application-specific contexts for version 1.0. Deprecated in TGA version 2.0 specification. |
| Mac OS file type | TPIC |
Documented in TGA version 2 specification. |
| Wikidata Title ID | Q1063976 |
See https://www.wikidata.org/wiki/Q1063976. |
| Pronom PUID | x-fmt/367 |
See https://www.nationalarchives.gov.uk/PRONOM/x-fmt/367. |
| General | |
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| History | Truevision defined the first version of its TGA file format in 1984 for use with its first videographics products, including video boards for PC displays. In 1989, Truevision introduced TGA version 2.0. The new version was designed to allow software that worked with version 1.0 to work with version 2.0 images (ignoring the added functionality). |
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