# Change Color Palette (OSC 4) > Set and query the colors that SGR's color numbers stand for. - **Sequence:** `OSC 4 ; Pc ; Pt ST` - **ECMA-48:** [§8.3.89 OSC – Operating System Command, p. 51](https://archive.org/details/ecma-48-5th-edition-june-1991/page/n64/mode/1up) - **xterm:** [Operating System Commands](https://invisible-island.net/xterm/ctlseqs/ctlseqs.html) The terminal's palette is the 256 colors that [SGR](https://control-codes.page/csi/sgr/index.html.md)'s color numbers stand for: `CSI 31 m` uses color 1, `CSI 38 ; 5 ; 196 m` color 196. `OSC 4 ; Pc ; Pt ST` changes color `Pc` to `Pt`, and [`OSC 104 ; Pc ST`](https://control-codes.page/osc/reset-palette/index.html.md) puts it back as it started. These are xterm's. - `Pt` is a color in any form X11's `XParseColor` accepts: a name such as `red` or `light sky blue`, `#rrggbb`, or `rgb:rr/gg/bb`, where each part may have one to four hex digits. - `Pt` of `?` asks what the color is. The answer is `OSC 4 ; Pc ; rgb:rrrr/gggg/bbbb`, sixteen bits a part, ended with whichever of ST or BEL ended the question. - One sequence can carry several pairs, `OSC 4 ; 1 ; red ; 2 ; ? ST`, mixing changes and questions. xterm stops at the first color it cannot parse or number it does not have, and ignores the rest ([`ChangeAnsiColorRequest`](https://github.com/ThomasDickey/xterm-snapshots/blob/xterm-411a/misc.c#L2980-L3029), [`ReportAnsiColorRequest`](https://github.com/ThomasDickey/xterm-snapshots/blob/xterm-411a/misc.c#L2636-L2659)). - DECSTR and RIS both reset the palette ([`ReallyReset`](https://github.com/ThomasDickey/xterm-snapshots/blob/xterm-411a/charproc.c#L14402-L14407)). Where the palette starts is the host's choice, made in xterm with resources such as `color1`. The cases are run in a terminal given a default xterm's: black, `red3`, `green3`, `yellow3`, `blue2`, `magenta3`, `cyan3` and `gray90`, then their bright versions, for colors 0 to 15 ([`charproc.c`](https://github.com/ThomasDickey/xterm-snapshots/blob/xterm-411a/charproc.c#L650-L665)), and the 6×6×6 cube and the gray ramp for 16 to 255 ([`256colres.h`](https://github.com/ThomasDickey/xterm-snapshots/blob/xterm-411a/256colres.h)). The answers assume a 24-bit display, where xterm reports each part of a color as its eight bits repeated, `cd` as `cdcd`. xterm also has [`OSC 5`](https://control-codes.page/osc/special-colors/index.html.md) and [`OSC 105`](https://control-codes.page/osc/reset-special-colors/index.html.md), which work the same way on its *special* colors, the ones it can use for bold, underlined, blinking, reversed and italic text. libghostty-vt does keep the palette through DECSTR, but its DECSTR is not implemented at all (see [DECSTR](https://control-codes.page/csi/decstr/index.html.md)). ## Support | Terminal | Version | Support | Notes | | --- | --- | --- | --- | | VT220 | [manual](https://vt100.net/docs/vt220-rm/), 2nd ed., 1984 | No | OSC is not among the controls it recognizes ([§4.2](https://vt100.net/docs/vt220-rm/chapter4.html#S4.2)) | | VT510 | [manual](https://vt100.net/docs/vt510-rm/), 1st ed., 1993 | No | ignores an OSC string ([chapter 4](https://vt100.net/docs/vt510-rm/chapter4.html)) | | xterm | patch 412, [xterm-411a](https://github.com/ThomasDickey/xterm-snapshots/tree/xterm-411a) | Yes | | | libghostty-vt | [0f171f6](https://github.com/ghostty-org/ghostty/tree/0f171f650a1cbbd6df4a2573b6b0c7de57cc6d90) | Yes | DECSTR does not reset it, having no DECSTR (OSC4-8) | | Konsole | 26.11.70, [a24c3d71](https://invent.kde.org/utilities/konsole/-/tree/a24c3d71be3684f24d030aa2dbe9bd723d985233) | Partly | answers only the first `?` in a list, and sets every color in a list to the first one's | | kitty | 0.49.1, [run in a VM](https://git.jcollie.dev/jeff/control-codes/src/branch/main/emulators/results/kitty.json) | Partly | fails OSC4-4 of the 3 cases that show it working; ends its replies with ST where xterm uses BEL | | foot | 1.28.0, [run in a VM](https://git.jcollie.dev/jeff/control-codes/src/branch/main/emulators/results/foot.json) | Partly | fails OSC4-5 of the 2 cases that show it working | | pyte | 0.8.2, [run as a library](https://git.jcollie.dev/jeff/control-codes/src/branch/main/emulators/results/pyte.json) | No | fails the 3 cases that show it working | | xterm.js headless | 6.0.0, [run as a library](https://git.jcollie.dev/jeff/control-codes/src/branch/main/emulators/results/xtermjs.json) | No | fails the 3 cases that show it working | | alacritty_terminal | 0.26.0, [run as a library](https://git.jcollie.dev/jeff/control-codes/src/branch/main/emulators/results/alacritty.json) | Partly | fails OSC4-5 of the 3 cases that show it working | | ConEmu | build 230724, its [documentation](https://conemu.github.io/en/AnsiEscapeCodes.html) | No | not in its [ANSI escape codes](https://conemu.github.io/en/AnsiEscapeCodes.html) | | rxvt-unicode | 9.31, [run in a VM](https://git.jcollie.dev/jeff/control-codes/src/branch/main/emulators/results/urxvt.json) | Partly | fails OSC4-4, OSC4-7 of the 3 cases that show it working; writes colors as `ff00` where xterm writes `ffff` | | VTE | 0.84.1, [run as a library](https://git.jcollie.dev/jeff/control-codes/src/branch/main/emulators/results/vte.json) | Partly | fails OSC4-5 of the 3 cases that show it working | ## Validation ### OSC4-1: Ask for a color Input, one step per line: ```text \e]4;1;?\a ``` Expected screen: ```text |____| reply \e]4;1;rgb:cdcd/0000/0000\a ``` ### OSC4-2: The answer ends as the question did Input, one step per line: ```text \e]4;12;?\e\\ ``` Expected screen: ```text |____| reply \e]4;12;rgb:5c5c/5c5c/ffff\e\\ ``` ### OSC4-3: From the cube and the gray ramp Input, one step per line: ```text \e]4;196;?;244;?\a ``` Expected screen: ```text |____| reply \e]4;196;rgb:ffff/0000/0000\a\e]4;244;rgb:8080/8080/8080\a ``` ### OSC4-4: Change a color, and text drawn in it Input, one step per line: ```text \e[31mA \e]4;1;#123456\a \e]4;1;?\a ``` Expected screen: ```text |A___| attr 1,1 fg=#123456 reply \e]4;1;rgb:1212/3434/5656\a ``` ### OSC4-5: By name, and by rgb: Input, one step per line: ```text \e]4;1;light sky blue;2;rgb:f/80/abc\a \e]4;1;?;2;?\a ``` Expected screen: ```text |____| reply \e]4;1;rgb:8787/cece/fafa\a\e]4;2;rgb:ffff/8080/abab\a ``` ### OSC4-6: A color it cannot parse stops the rest Input, one step per line: ```text \e]4;1;nosuch;2;red\a \e]4;1;?;2;?\a ``` Expected screen: ```text |____| reply \e]4;1;rgb:cdcd/0000/0000\a\e]4;2;rgb:0000/cdcd/0000\a ``` ### OSC4-7: RIS resets the palette Input, one step per line: ```text \e]4;1;red\a \ec \e]4;1;?\a ``` Expected screen: ```text |____| reply \e]4;1;rgb:cdcd/0000/0000\a ``` ### OSC4-8: So does DECSTR *A known difference: libghostty-vt does not pass this case.* Input, one step per line: ```text \e]4;1;red\a \e[!p \e]4;1;?\a ``` Expected screen: ```text |____| reply \e]4;1;rgb:cdcd/0000/0000\a ``` --- This is the Markdown version of . On that page every validation case runs live in libghostty-vt, the terminal emulation core of Ghostty, compiled to WebAssembly. The validation cases are written in the notation described in .