diff --git a/crates/engine/src/cmd/colormgmt.rs b/crates/engine/src/cmd/colormgmt.rs
index 9b3378fc..a71a404a 100644
--- a/crates/engine/src/cmd/colormgmt.rs
+++ b/crates/engine/src/cmd/colormgmt.rs
@@ -111,7 +111,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "Overprint Black…",
             ["Edit", "Edit Colors"],
             None,
-            "{remove?: false, percentage?: 100, ids?} make the black fills and strokes (black-only ink ≥ percentage) of the selection (or ids; groups: their contents) overprint, or stop (remove) → {changed: objects}",
+            "{remove?: false, percentage?: 100, fill?: true, stroke?: true, includeCmyBlacks?: false, includeSpotBlacks?: false, ids?} make the black fills and/or strokes of the selection (or ids; groups: their contents; type: its characters) overprint, or stop (remove). Black: K ≥ percentage with no C, M or Y (any with includeCmyBlacks), not linked to a spot swatch (unless includeSpotBlacks); a gradient is black when every stop is → {changed: objects}",
             has_doc,
             super::overprint::overprint_black
         ),
diff --git a/crates/engine/src/cmd/overprint.rs b/crates/engine/src/cmd/overprint.rs
index 60fda0cf..eae8acb3 100644
--- a/crates/engine/src/cmd/overprint.rs
+++ b/crates/engine/src/cmd/overprint.rs
@@ -189,7 +189,10 @@ pub(crate) fn overprint_black(s: &mut Session, p: &Value) -> Result<Value> {
     let op = OverprintBlack {
         remove: bool_or(p, "remove", false),
         min_k: (f64_or(p, "percentage", 100.0) / 100.0).clamp(0.0, 1.0) as f32,
-        ..Default::default()
+        fill: bool_or(p, "fill", true),
+        stroke: bool_or(p, "stroke", true),
+        rich: bool_or(p, "includeCmyBlacks", false),
+        spot: bool_or(p, "includeSpotBlacks", false),
     };
     let ids = match ids_param(p, "ids") {
         Some(v) => v,
diff --git a/crates/engine/src/tests_overprint.rs b/crates/engine/src/tests_overprint.rs
index 81570e6f..78950a83 100644
--- a/crates/engine/src/tests_overprint.rs
+++ b/crates/engine/src/tests_overprint.rs
@@ -192,3 +192,63 @@ fn old_documents_with_an_overprint_black_list_still_preview() {
     let back = vectorcraft_format::load(&vectorcraft_format::save(&doc, false)).unwrap();
     assert_eq!(back.node(k).unwrap().appearance, n.appearance);
 }
+
+fn overprints(s: &Session, id: NodeId) -> (bool, bool) {
+    let a = &node(s, id).appearance;
+    (a.fill().unwrap().overprint, a.stroke().unwrap().overprint)
+}
+
+#[test]
+fn overprint_black_options() {
+    let mut s = session();
+    let k = rect(&mut s, [0.0, 0.0, 10.0, 10.0], black_ink(), Some(black_ink()), 1.0);
+    let rich = rect(&mut s, [20.0, 0.0, 10.0, 10.0], ink(60, 40, 40, 100), Some(ink(0, 0, 0, 80)), 1.0);
+    let rgb = rect(&mut s, [40.0, 0.0, 10.0, 10.0], json!("#000000"), Some(cyan_ink()), 1.0);
+    let ids = json!([k.0, rich.0, rgb.0]);
+
+    let r = s.execute("edit.colors.overprintBlack", &json!({"ids": ids, "fill": false})).unwrap();
+    assert_eq!(r["changed"], 1);
+    assert_eq!(overprints(&s, k), (false, true), "fill: false marks strokes only");
+    s.execute("edit.colors.overprintBlack", &json!({"ids": ids})).unwrap();
+    assert_eq!(overprints(&s, k), (true, true));
+    assert_eq!(overprints(&s, rich), (false, false), "rich black and 80% K stay out at 100%");
+    assert_eq!(overprints(&s, rgb), (false, false), "RGB black is not black ink");
+
+    let before = undo_len(&s);
+    s.execute("edit.colors.overprintBlack", &json!({"ids": ids, "includeCmyBlacks": true})).unwrap();
+    assert_eq!(overprints(&s, rich), (true, false), "rich black included with CMY");
+    assert_eq!(undo_len(&s), before + 1, "one undo step");
+    s.execute("edit.colors.overprintBlack", &json!({"ids": ids, "percentage": 75})).unwrap();
+    assert_eq!(overprints(&s, rich), (true, true), "80% K at 75%");
+
+    s.execute("edit.colors.overprintBlack", &json!({"ids": ids, "remove": true, "stroke": false, "includeCmyBlacks": true})).unwrap();
+    assert_eq!((overprints(&s, k), overprints(&s, rich)), ((false, true), (false, true)), "remove from fills only");
+    let before = undo_len(&s);
+    let r = s.execute("edit.colors.overprintBlack", &json!({"ids": ids, "remove": true, "stroke": false})).unwrap();
+    assert_eq!((r["changed"].clone(), undo_len(&s)), (json!(0), before), "nothing to change, no undo step");
+}
+
+#[test]
+fn overprint_black_covers_type_gradients_spots_and_groups() {
+    let mut s = session();
+    let t = NodeId(s.execute("text.create", &json!({"x": 10, "y": 50, "text": "Hi"})).unwrap()["id"].as_u64().unwrap());
+    s.execute("paint.setFill", &json!({"ids": [t.0], "color": black_ink()})).unwrap();
+    let g = rect(&mut s, [0.0, 0.0, 10.0, 10.0], black_ink(), None, 0.0);
+    let stops = json!([{"offset": 0, "color": black_ink()}, {"offset": 1, "color": ink(50, 0, 0, 100)}]);
+    s.execute("paint.setFill", &json!({"ids": [g.0], "gradient": {"stops": stops}})).unwrap();
+    let spot = rect(&mut s, [20.0, 0.0, 10.0, 10.0], black_ink(), None, 0.0);
+    let name =
+        s.execute("swatch.new", &json!({"name": "Press Black", "color": black_ink(), "spot": true})).unwrap()["name"].as_str().unwrap().to_string();
+    s.execute("paint.setFill", &json!({"ids": [spot.0], "swatch": name})).unwrap();
+    s.execute("select.set", &json!({"ids": [t.0, g.0, spot.0]})).unwrap();
+    s.execute("object.group", &json!({})).unwrap();
+
+    s.execute("edit.colors.overprintBlack", &json!({})).unwrap();
+    let NodeKind::Text(tx) = &node(&s, t).kind else { panic!() };
+    assert!(tx.runs.iter().all(|r| r.style.overprint_fill), "type characters, inside the selected group");
+    let fill = |s: &Session, id| node(s, id).appearance.fill().unwrap().overprint;
+    assert!(!fill(&s, g), "a gradient with a rich-black stop");
+    assert!(!fill(&s, spot), "spot blacks need includeSpotBlacks");
+    s.execute("edit.colors.overprintBlack", &json!({"includeCmyBlacks": true, "includeSpotBlacks": true})).unwrap();
+    assert!(fill(&s, g) && fill(&s, spot));
+}
diff --git a/crates/ui-egui/src/dialogs/form.rs b/crates/ui-egui/src/dialogs/form.rs
index e6b7aa06..5a2744d7 100644
--- a/crates/ui-egui/src/dialogs/form.rs
+++ b/crates/ui-egui/src/dialogs/form.rs
@@ -133,6 +133,7 @@ pub(super) fn humanize(k: &str) -> String {
         "Sy" => "Vertical %".into(),
         "Radius1" => "Radius 1".into(),
         "Radius2" => "Radius 2".into(),
+        "Include Cmy Blacks" => "Include Blacks with CMY:".into(),
         _ => format!("{s}:"),
     }
 }
diff --git a/crates/ui-egui/src/lib.rs b/crates/ui-egui/src/lib.rs
index 08a13ff2..4fea0cde 100644
--- a/crates/ui-egui/src/lib.rs
+++ b/crates/ui-egui/src/lib.rs
@@ -33,6 +33,8 @@ pub mod workspaces;
 
 #[cfg(test)]
 mod tests_labels;
+#[cfg(test)]
+mod tests_overprint;
 
 use std::sync::mpsc::{Receiver, Sender};
 use std::sync::{Arc, Mutex};
diff --git a/crates/ui-egui/src/menus.rs b/crates/ui-egui/src/menus.rs
index bce706c9..5c682e7b 100644
--- a/crates/ui-egui/src/menus.rs
+++ b/crates/ui-egui/src/menus.rs
@@ -788,7 +788,11 @@ pub fn menu_tree() -> Vec<(&'static str, Vec<Item>)> {
                         c("Convert to Grayscale", "edit.colors.toGrayscale"),
                         c("Convert to RGB", "edit.colors.toRGB"),
                         c("Invert Colors", "edit.colors.invert"),
-                        c("Overprint Black…", "edit.colors.overprintBlack"),
+                        cp(
+                            "Overprint Black…",
+                            "edit.colors.overprintBlack",
+                            json!({"remove": false, "percentage": 100, "fill": true, "stroke": true, "includeCmyBlacks": false, "includeSpotBlacks": false}),
+                        ),
                         cp("Saturate…", "edit.colors.saturate", json!({"intensity": 20})),
                     ],
                 ),
diff --git a/crates/ui-egui/src/tests_labels.rs b/crates/ui-egui/src/tests_labels.rs
index 7907abce..f2f6ea21 100644
--- a/crates/ui-egui/src/tests_labels.rs
+++ b/crates/ui-egui/src/tests_labels.rs
@@ -13,8 +13,9 @@ fn app() -> VectorcraftApp {
     app
 }
 
-/// Every string painted by `f` in one headless frame, one per line.
-fn painted_text(app: &mut VectorcraftApp, mut f: impl FnMut(&mut VectorcraftApp, &mut egui::Ui)) -> String {
+/// Every string painted by `f` in a headless frame (app fonts installed), one per line. The second
+/// of two frames: windows size themselves invisibly in their first.
+pub(crate) fn painted_text(app: &mut VectorcraftApp, mut f: impl FnMut(&mut VectorcraftApp, &mut egui::Ui)) -> String {
     fn collect(s: &Shape, out: &mut String) {
         match s {
             Shape::Text(t) => {
@@ -26,6 +27,8 @@ fn painted_text(app: &mut VectorcraftApp, mut f: impl FnMut(&mut VectorcraftApp,
         }
     }
     let ctx = egui::Context::default();
+    crate::theme::install_fonts(&ctx);
+    ctx.run_ui(egui::RawInput::default(), |ui| f(app, ui)).textures_delta.clear();
     let mut out = ctx.run_ui(egui::RawInput::default(), |ui| f(app, ui));
     out.textures_delta.clear();
     let mut text = String::new();
diff --git a/crates/ui-egui/src/tests_overprint.rs b/crates/ui-egui/src/tests_overprint.rs
new file mode 100644
index 00000000..3ebc43a5
--- /dev/null
+++ b/crates/ui-egui/src/tests_overprint.rs
@@ -0,0 +1,46 @@
+//! Edit → Edit Colors → Overprint Black… opens its parameter dialog, which applies the command.
+
+use serde_json::{Value, json};
+use vectorcraft_doc::NodeId;
+use vectorcraft_engine::Session;
+
+use crate::{VectorcraftApp, dialogs, menus};
+
+#[test]
+fn overprint_black_menu_opens_the_dialog() {
+    let mut app = VectorcraftApp::new(Session::new(), Default::default());
+    app.run("file.new", json!({"width": 100, "height": 100})).unwrap();
+    let id = NodeId(app.run("shape.rectangle", json!({"x": 10, "y": 10, "width": 50, "height": 50})).unwrap()["id"].as_u64().unwrap());
+    let rich = json!({"c": 60, "m": 40, "y": 40, "k": 100});
+    app.run("paint.setFill", json!({"ids": [id.0], "color": rich})).unwrap();
+    app.run("paint.setStroke", json!({"ids": [id.0], "color": rich})).unwrap();
+    app.run("select.set", json!({"ids": [id.0]})).unwrap();
+
+    let entry = menus::menu_entries(&app).into_iter().find(|e| e.label == "Overprint Black…").expect("menu item");
+    assert_eq!(entry.path, ["Edit", "Edit Colors"]);
+    assert!(entry.enabled);
+    let (cmd, params) = menus::click_target(&entry.label, entry.command.as_deref().unwrap(), &entry.params);
+    menus::invoke(&mut app, &cmd, params);
+    let d = app.ui.dialog.as_ref().expect("a dialog opens");
+    assert_eq!((d.str("__command"), d.str("__label")), ("edit.colors.overprintBlack".to_string(), "Overprint Black".to_string()));
+    for (k, v) in
+        [("remove", json!(false)), ("percentage", json!(100)), ("fill", json!(true)), ("stroke", json!(true)), ("includeCmyBlacks", json!(false))]
+    {
+        assert_eq!(d.fields.get(k), Some(&v), "{k}");
+    }
+
+    // It draws headlessly, with its options labelled.
+    let text = crate::tests_labels::painted_text(&mut app, |app, ui| dialogs::show(app, ui.ctx()));
+    for label in ["Overprint Black", "Percentage:", "Include Blacks with CMY:", "Include Spot Blacks:", "Remove:"] {
+        assert!(text.contains(label), "{label} in {text}");
+    }
+
+    // Fill only, with rich blacks: the stroke stays knocked out.
+    let d = app.ui.dialog.as_mut().unwrap();
+    d.fields.insert("includeCmyBlacks".into(), Value::Bool(true));
+    d.fields.insert("stroke".into(), Value::Bool(false));
+    dialogs::confirm(&mut app).unwrap();
+    assert!(app.ui.dialog.is_none());
+    let a = &app.session.doc().unwrap().doc.node(id).unwrap().appearance;
+    assert!(a.fill().unwrap().overprint && !a.stroke().unwrap().overprint);
+}
diff --git a/docs/control-protocol.md b/docs/control-protocol.md
index 6cfa113f..5369c64a 100644
--- a/docs/control-protocol.md
+++ b/docs/control-protocol.md
@@ -60,3 +60,7 @@ effects) prefilled with its values, and `ui.dialog.confirm` runs `effect.setPara
 `effect.apply`. Choosing an effect that the list already has returns `{"pending": "effectExists"}` and opens the
 `effectExists` question: `ui.dialog.confirm` opens the applied effect's dialog, `ui.dialog.set {field: "discard",
 value: true}` then confirm opens a fresh one that adds another, `ui.dialog.cancel` drops it.
+
+Overprint Black: the Edit → Edit Colors → Overprint Black… menu item opens a `command` parameter dialog for
+`edit.colors.overprintBlack` (fields `remove`, `percentage`, `fill`, `stroke`, `includeCmyBlacks`,
+`includeSpotBlacks`); `ui.dialog.set` then `ui.dialog.confirm` runs it on the selection.