# Color Graphics Adapter

> computer display standard

**Wikidata**: [Q725893](https://www.wikidata.org/wiki/Q725893)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Color_Graphics_Adapter)  
**Source**: https://4ort.xyz/entity/color-graphics-adapter

## Summary
The Color Graphics Adapter (CGA) is an early computer display standard introduced by IBM in 1981, serving as the first widespread color graphics specification for PCs. It supported resolutions such as 320×200 with 4 colors or 640×200 in monochrome, establishing a foundational benchmark for color display capabilities in the burgeoning personal computer market.

## Key Facts
- **Inception**: 1981, developed by IBM.
- **Resolutions**: 320×200 (4 colors), 640×200 (monochrome), and 160×100 (16 colors via composite output).
- **Color Depth**: 4-bit (16 colors total, 4 simultaneous on RGB monitors).
- **Refresh Rate**: 60 Hz.
- **Significance**: First color display standard for IBM PCs, enabling color graphics in gaming and business applications.
- **Aliases**: CGA, IBM Color Graphics Adapter, C.G.A.
- **Related Standards**: Preceded by MDA (Monochrome Display Adapter); succeeded by EGA (1984) and VGA (1987).
- **Technical Classification**: Subclass of computer display standard, graphics card, and technical standard.
- **Hardware**: Utilized an RCA connector for composite video and a 9-pin DE-9 connector for RGB output.
- **Legacy**: 640×200 resolution became a baseline for early PC software; 16-color palette influenced later standards.
- **Freebase ID**: /m/02dwht.
- **Wikidata Sitelink Count**: 27; Wikipedia articles in 28 languages.
- **Regional Variants**: Supported by Tandy 1000’s enhanced CGA with 16 colors.

## FAQs
### Q: What does CGA stand for, and why was it important?
A: CGA stands for Color Graphics Adapter. It was pivotal as IBM’s first color display standard for PCs, introducing color graphics to a market previously dominated by monochrome systems like the MDA.

### Q: What were CGA’s key technical specifications?
A: CGA supported 320×200 resolution with 4 colors or 640×200 in monochrome, with a 16-color palette and 60 Hz refresh rate. It used analog RGB signaling and composite video output.

### Q: How did CGA differ from later standards like EGA and VGA?
A: CGA offered limited color and resolution compared to EGA (1984), which doubled resolution and expanded the palette to 64 colors, and VGA (1987), which introduced 640×480 resolution with 256 colors.

### Q: Is CGA still relevant today?
A: While obsolete for modern displays, CGA’s 640×200 resolution and 16-color palette remain recognizable in retro computing and demoscene communities. Its legacy also persists in the use of “CGA” as shorthand for low-color retro aesthetics.

## Why It Matters
The Color Graphics Adapter democratized access to color computing, transitioning PCs from monochrome text terminals to graphical workstations. By standardizing color output, CGA enabled the growth of graphical user interfaces (GUIs), educational software, and the nascent video game industry. Its role as a baseline specification ensured hardware and software interoperability, fostering an ecosystem where developers could create color-enabled applications without worrying about display incompatibility. CGA’s limitations also drove innovation, pushing the development of higher-resolution successors like EGA and VGA, which further expanded the PC’s graphical capabilities. Historically, CGA represents a critical milestone in the evolution of computer graphics, bridging the gap between early adopters and the mass market.

## Notable For
- **First Color PC Standard**: Established color graphics as a core PC feature in 1981.
- **Technical Innovation**: Introduced 4-bit color depth and multiple resolution modes on a single hardware platform.
- **Cultural Impact**: Defined the visual identity of 1980s PC gaming (e.g., *King’s Quest*, *Ultima IV*) and business software.
- **Regional Adaptations**: Supported by third-party systems like the Tandy 1000, which enhanced CGA with additional colors.
- **Legacy in Modern Systems**: 640×480 “VGA” resolution retains CGA’s horizontal pixel count, reflecting its enduring influence.

## Body
### Definition and Scope
The Color Graphics Adapter (CGA) is a computer display standard introduced by IBM in 1981 to provide color graphics capabilities for its PC line. As a technical specification, CGA defined resolution, color depth, and refresh rate parameters, ensuring compatibility between graphics cards and monitors. It supported two primary modes: **320×200 pixels with 4 colors** (selected from a 16-color palette) and **640×200 pixels in monochrome**. A third mode, **160×100 pixels with 16 colors**, was achievable via composite video output, though rarely utilized due to quality limitations.

### Historical Context
CGA emerged as a response to the growing demand for graphical computing, succeeding IBM’s monochrome-only MDA (1981). While MDA offered superior text clarity (360×200 resolution), CGA’s color support revolutionized applications such as gaming, CAD, and multimedia. The standard’s 16-color palette, derived from the RGBI (Red, Green, Blue, Intensity) color model, became iconic in 1980s software. Notable adopters included the Tandy 1000, which expanded CGA’s palette to 16 simultaneous colors through proprietary hardware tweaks.

### Technical Specifications
- **Resolution**: 320×200 (4 colors), 640×200 (monochrome), 160×100 (16 colors via composite).
- **Color Depth**: 4-bit (16-color palette, 4 colors per screen in RGB mode).
- **Refresh Rate**: 60 Hz.
- **Connectors**: 9-pin DE-9 for RGB output, RCA for composite video.
- **Memory**: 16 KB video RAM, limiting resolution and color combinations.

### Related Standards and Evolution
CGA’s limitations—particularly its low resolution and color constraints—spurred rapid advancement in display technology. Key successors include:
- **Enhanced Graphics Adapter (EGA, 1984)**: Doubled resolution to 640×350 and expanded the palette to 64 colors.
- **Video Graphics Array (VGA, 1987)**: Introduced 640×480 resolution with 256 colors, becoming the de facto PC standard for over a decade.
- **Regional Variants**: Japan’s JEGA (1980s) adapted CGA for localized text processing, while the Tandy Graphics Adapter (1984) enhanced color output on compatible systems.

### Legacy and Modern Relevance
Though CGA hardware was phased out by the early 1990s, its influence persists in:
- **Retro Computing**: Emulators and vintage gaming communities continue to celebrate CGA’s aesthetic, with modern indie games (e.g., *Shovel Knight*) incorporating CGA-inspired visuals.
- **Resolution Terminology**: The “640×480” resolution, later popularized by VGA, retains CGA’s horizontal pixel count as a nod to its foundational role.
- **Digital Preservation**: Archives like the Internet Archive emulate CGA displays to ensure historical software remains accessible.

### Cultural Impact
CGA’s 16-color palette shaped the visual language of 1980s software, from the vibrant hues of *Myst* to the blocky textures of early business charts. Its limitations also fostered creativity, with developers employing dithering and palette cycling techniques to simulate greater color depth. This ingenuity laid groundwork for later graphical innovations, including the Amiga’s Hold-And-Modify (HAM) mode and VGA’s 256-color truecolor capabilities.

## References

1. Freebase Data Dumps. 2013