emulation for use on modern chunky graphics hardware. Dedicated Amiga emulators running on non-native hardware are able to display HAM mode by emulation of the display hardware. However, since no other computer architecture used the HAM technique, viewing a HAM image on any other architecture requires programmatic interpretation of the image file. Faithful software-based decoding will produce identical results, setting aside variations in color fidelity between display setups. However, if the goal is merely to display a SHAM image on a non-Amiga platform, the required color values may be pre-calculated based on the palette entries that are programmed via the copper-list, regardless of whether the palette is modified in the middle of a scanline. It is always possible to up-convert a HAM or SHAM image losslessly to a 32-bit palette. Third-party HAM implementations A device produced by Black Belt known as HAM-E was able to produce images with HAM8 color depth at low horizontal resolution from an Amiga with an Original Chipset. The Amiga would be set up to produce high resolution images (640 pixels wide, 720 with overscan). This required the use of four bitplanes at 70 ns per pixel. The first few lines of the image encoded information to configure the HAM-E unit. Then each pair of pixels was encoded with information for the HAM-E unit, which converted the information into one 140 ns pixel (generating an image 320 pixels wide, or 360 with overscan, at a color depth of eight bitplanes). The quality of HAM-E was thus comparable to a low-resolution HAM8 image. The HAM-E technique exploited the fact that a high resolution image with four bitplanes delivers a third more memory bandwidth, and therefore a third more data, than a low resolution image with six bitplanes. The HAM technique was also implemented on the HAM256 and HAM8x1 modes of ULAplus for the ZX Spectrum, where it provides the ability to display 256 colors on screen, by modifying a base 64 color palette. See also Original Chip Set Amiga Halfbrite mode Sony ARW 2.0 (ARW 2.0+ raw image files use a similar technique for their lossy delta-compression) References Further reading Specification for the Advanced Amiga (AA) Chip Set, Commodore-Amiga External links An animated demo rendered in HAM mode: HAM-6 version, and HAM-8 version (Java required). Amiga Graphics Archive: HAM Computer display standards Amiga Color depths