diff --git a/index.pug b/index.pug
index d161e67..be17ae4 100644
--- a/index.pug
+++ b/index.pug
@@ -62,6 +62,12 @@ html(lang="en-gb")
                                     | palette
                                     select#palette
 
+                                #new-palette(style="display: none;")
+                                    .half
+                                        input#colour-background(type="color" value="#2f4ac9")
+                                    .half
+                                        input#colour-foreground(type="color" value="#8798fe")
+
                                 label
                                     input#dither(type="checkbox" checked=true)
                                     | dither
diff --git a/script.js b/script.js
index 66d12b8..28c46e6 100644
--- a/script.js
+++ b/script.js
@@ -72,7 +72,10 @@ async function run() {
     const buttonNewGame          = el("new");
     const buttonReset            = el("reset");
     const checkboxDither         = el("dither");
+    const divNewPalette          = el("new-palette");
     const inputBrightness        = el("brightness");
+    const inputColourBackground  = el("colour-background");
+    const inputColourForeground  = el("colour-foreground");
     const inputRoomName          = el("room-name");
     const selectPalette          = el("palette");
     const textareaGameDataInput  = el("game-data");
@@ -126,6 +129,11 @@ async function run() {
 
         selectPalette.innerHTML = "";
 
+        palettes.push({
+            id: "NEW_PALETTE",
+            name: "new palette"
+        });
+
         for (let palette of palettes) {
             let option = document.createElement("option");
 
@@ -174,10 +182,25 @@ async function run() {
     buttonImageProceed.addEventListener("touchend", handleImage);
 
     selectPalette.addEventListener("change", () => {
-        set_palette(selectPalette.value);
+        set_palette(selectPalette.value, inputColourBackground.value, inputColourForeground.value);
+
+        if (selectPalette.value === "NEW_PALETTE") {
+            divNewPalette.style.display = "block";
+        } else {
+            divNewPalette.style.display = "none";
+        }
+
         loadPreview();
     });
 
+    function updateCustomPalette() {
+        set_palette(selectPalette.value, inputColourBackground.value, inputColourForeground.value);
+        loadPreview();
+    }
+
+    inputColourForeground.addEventListener("change", updateCustomPalette);
+    inputColourBackground.addEventListener("change", updateCustomPalette);
+
     checkboxDither.addEventListener("change", () => {
         set_dither(checkboxDither.checked);
         loadPreview();
diff --git a/src/lib.rs b/src/lib.rs
index 9a6ceaf..5d42374 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -16,11 +16,22 @@ use colour_map::ColourMap;
 
 const SD: u32 = 8;
 
+enum SelectedPalette {
+    None,
+    Existing {
+        id: String,
+    },
+    New {
+        background: bitsy_parser::Colour,
+        foreground: bitsy_parser::Colour,
+    }
+}
+
 struct State {
     game:       Option<Game>,
     image:      Option<DynamicImage>,
     room_name:  Option<String>,
-    palette:    Option<String>,
+    palette:    SelectedPalette,
     dither:     bool,
     brightness: i32,
 }
@@ -31,7 +42,7 @@ lazy_static! {
             game:       None,
             image:      None,
             room_name:  None,
-            palette:    None,
+            palette:    SelectedPalette::None,
             dither:     true,
             brightness: 0,
         }
@@ -49,8 +60,13 @@ fn tile_name(prefix: &Option<String>, index: &u32) -> Option<String> {
 #[wasm_bindgen]
 pub fn load_default_game()  {
     let mut state = STATE.lock().unwrap();
+
     state.game = Some(bitsy_parser::mock::game_default());
-    state.palette = Some(bitsy_parser::mock::game_default().palette_ids()[0].clone())
+
+    // yes, this will probably always just be "0", but to be safe…
+    state.palette = SelectedPalette::Existing {
+        id: bitsy_parser::mock::game_default().palette_ids()[0].clone()
+    }
 }
 
 #[wasm_bindgen]
@@ -63,12 +79,12 @@ pub fn load_game(game_data: String) -> String {
         Ok((game, _errs)) => {
             let palette_id = game.palette_ids()[0].clone();
             state.game    = Some(game);
-            state.palette = Some(palette_id);
+            state.palette = SelectedPalette::Existing { id: palette_id };
             format!("Loaded game")
         },
         _ => {
             state.game    = None;
-            state.palette = None;
+            state.palette = SelectedPalette::None;
             format!("{}", result.err().unwrap())
         }
     }
@@ -110,12 +126,16 @@ pub fn set_dither(dither: bool) {
 }
 
 #[wasm_bindgen]
-pub fn set_palette(palette_id: String) {
+pub fn set_palette(palette_id: &str, background: String, foreground: String) {
     let mut state = STATE.lock().unwrap();
 
-    match palette_id.is_empty() {
-        true  => { state.palette = None },
-        false => { state.palette = Some(palette_id) },
+    state.palette = match palette_id {
+        "NEW_PALETTE" => SelectedPalette::New {
+            background: bitsy_parser::Colour::from_hex(&background).unwrap(),
+            foreground: bitsy_parser::Colour::from_hex(&foreground).unwrap(),
+        },
+        "" => SelectedPalette::None,
+        _             => SelectedPalette::Existing { id: palette_id.to_string() },
     }
 }
 
@@ -166,10 +186,22 @@ fn image_to_base64(image: &DynamicImage) -> String {
 
 fn render_preview(state: &State) -> DynamicImage {
     let mut buffer = state.image.as_ref().unwrap().clone().into_rgba();
-    let     palette_id   = state.palette.as_ref().unwrap();
-    let     palette     = *&state.game.as_ref().unwrap().get_palette(palette_id).unwrap();
-    let     colour_map = crate::ColourMap::from(palette);
 
+    let palette = match &state.palette {
+        SelectedPalette::None => bitsy_parser::mock::game_default().palettes[0].clone(),
+        SelectedPalette::Existing { id } => state.game.as_ref().unwrap().get_palette(id).unwrap().clone(),
+        SelectedPalette::New { background, foreground } => Palette {
+            id: "0".to_string(),
+            name: None,
+            colours: vec![
+                background.clone(), foreground.clone(), Colour { red: 0, green: 0, blue: 0 }
+            ],
+        },
+    };
+
+    let colour_map = crate::ColourMap::from(&palette);
+
+    // adjust brightness
     let mut buffer = image::imageops::brighten(&mut buffer, state.brightness);
 
     if state.dither {