Sunday, March 26, 2023

IBM Composite Artifact Color Games and Related Topics

Top - Direct Colors Old CGA & New CGA
Bottom - High Resolution Artifact Colors Old CGA & New CGA

Back in 2013 I gave an overview of composite color usage on the IBM PC platform.  I included a list of all games I knew about or could find which supported composite color graphics.  Now, 10 years later, new information has made that list less than inaccurate and less than fully inclusive.  Let's talk about these games and give a new, more accurate list.  I will also talk about other topics related to CGA and color in more detail below.  

Friday, March 3, 2023

The Saga of the Color Brown in the Early Years of the PC

top left: RGB monitor without intensity bit, bottom left: RGBI monitor without brown correction, top right: RGBI monitor with 33% brown reduction (IBM 5153), bottom right: RGBI monitor with 50% brown reduction (EGA/VGA/Tandy)

In 1980-81 IBM developed a graphics card for its new IBM PC called the Color/Graphics Adapter.  This card was designed to display 16 colors on a compatible CRT monitor via a 9-pin digital video port.  IBM defined the colors in its Technical Reference Manual using a 4-bit binary code.  The CGA could also display colors with a composite video connector on the card.  It is the evolution of the display of one of those colors, color 6, commonly but yet simplistically referred to as brown, that we are interested in today.