Hold-and-modify or HAM as it is usually abbreviated to, was an enhanced graphics mode built into Amiga computers. It was part of the reason why Amigas were so popular, giving them a huge advantage over the competition (PC, Atari, Macs) in terms of screen resolution and colours making them perfect for games and video editing.
You can find out more about HAM-6 and HAM-8 on wikipedia.
The Amiga ignited my huge passion for interactive arts; so it seems only fitting that I should name my site after the screen mode which made it all possible.
“Hold and Modify came from a trip to see flight simulators in action and I had a kind of idea about a primitive type of virtual reality. NTSC on the chip meant you could hold the hue and change the luminance by only altering four bits. When we changed to RGB I said that wasn’t needed any more as it wasn’t useful and I asked the chip layout guy to take it off. He came back and said that this would either leave a big hole in the middle of the chip or take a three-month redesign and we couldn’t do that. I didn’t think anyone would use it. I was wrong again as that has really given the Amiga its edge in terms of the color palette.”
Jay Miner, inventor of the Amiga computer
A fab quote – I love stories like this. Human error in the design process (as it could be percieved by the designer) can sometimes introduce a unique and unintended strength to a product.