diff --git a/src/bootstrap_gui.cpp b/src/bootstrap_gui.cpp
index 7202bfa6a9..88057c6335 100644
--- a/src/bootstrap_gui.cpp
+++ b/src/bootstrap_gui.cpp
@@ -386,10 +386,10 @@ bool HandleBootstrap()
 	/* Initialise the palette. The biggest step is 'faking' some recolour sprites.
 	 * This way the mauve and gray colours work and we can show the user interface. */
 	GfxInitPalettes();
-	static const uint8_t offsets[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x80, 0, 0, 0, 0x04, 0x08 };
+	static const EnumIndexArray<uint8_t, Colours, Colours::End> offsets = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x80, 0, 0, 0, 0x04, 0x08 };
 	for (Colours i = Colours::Begin; i != Colours::End; i++) {
-		for (ColourShade j = SHADE_BEGIN; j < SHADE_END; j++) {
-			SetColourGradient(i, j, PixelColour(offsets[to_underlying(i)] + j));
+		for (Shade j = Shade::Begin; j < Shade::End; j++) {
+			SetColourGradient(i, j, PixelColour(offsets[i] + to_underlying(j)));
 		}
 	}
 
diff --git a/src/build_vehicle_gui.cpp b/src/build_vehicle_gui.cpp
index 86ad70d048..98990e0b98 100644
--- a/src/build_vehicle_gui.cpp
+++ b/src/build_vehicle_gui.cpp
@@ -934,7 +934,7 @@ void DrawEngineList(VehicleType type, const Rect &r, const GUIEngineList &eng_li
 	int sprite_right = GetVehicleImageCellSize(type, EIT_PURCHASE).extend_right;
 	int sprite_width = sprite_left + sprite_right;
 	int circle_width = std::max(GetScaledSpriteSize(SPR_CIRCLE_FOLDED).width, GetScaledSpriteSize(SPR_CIRCLE_UNFOLDED).width);
-	PixelColour linecolour = GetColourGradient(Colours::Orange, SHADE_NORMAL);
+	PixelColour linecolour = GetColourGradient(Colours::Orange, Shade::Normal);
 
 	auto badge_column_widths = badge_classes.GetColumnWidths();
 
diff --git a/src/company_cmd.cpp b/src/company_cmd.cpp
index 8333149346..8ecc9d7938 100644
--- a/src/company_cmd.cpp
+++ b/src/company_cmd.cpp
@@ -156,8 +156,8 @@ void SetLocalCompany(CompanyID new_company)
  */
 TextColour GetDrawStringCompanyColour(CompanyID company)
 {
-	if (!Company::IsValidID(company)) return GetColourGradient(Colours::White, SHADE_NORMAL).ToTextColour();
-	return GetColourGradient(_company_colours[company], SHADE_NORMAL).ToTextColour();
+	if (!Company::IsValidID(company)) return GetColourGradient(Colours::White, Shade::Normal).ToTextColour();
+	return GetColourGradient(_company_colours[company], Shade::Normal).ToTextColour();
 }
 
 /**
diff --git a/src/console_gui.cpp b/src/console_gui.cpp
index 6ad074ae1c..29a404167a 100644
--- a/src/console_gui.cpp
+++ b/src/console_gui.cpp
@@ -548,7 +548,7 @@ bool IsValidConsoleColour(TextColour c)
 	 * colour gradient, so it must be one of those. */
 	c &= ~TC_IS_PALETTE_COLOUR;
 	for (Colours i = Colours::Begin; i < Colours::End; i++) {
-		if (GetColourGradient(i, SHADE_NORMAL).p == c) return true;
+		if (GetColourGradient(i, Shade::Normal).p == c) return true;
 	}
 
 	return false;
diff --git a/src/depot_gui.cpp b/src/depot_gui.cpp
index 1329b3931f..3015e2f659 100644
--- a/src/depot_gui.cpp
+++ b/src/depot_gui.cpp
@@ -418,7 +418,7 @@ struct DepotWindow : Window {
 		 */
 		if (this->type == VehicleType::Train && _consistent_train_width != 0) {
 			int w = ScaleSpriteTrad(2 * _consistent_train_width);
-			PixelColour col = GetColourGradient(wid->colour, SHADE_NORMAL);
+			PixelColour col = GetColourGradient(wid->colour, Shade::Normal);
 			Rect image = ir.Indent(this->header_width, rtl).Indent(this->count_width, !rtl);
 			int first_line = w + (-this->hscroll->GetPosition()) % w;
 			if (rtl) {
diff --git a/src/dropdown_common_type.h b/src/dropdown_common_type.h
index 0607f0f0df..bcdb62dd61 100644
--- a/src/dropdown_common_type.h
+++ b/src/dropdown_common_type.h
@@ -38,8 +38,8 @@ public:
 
 	void Draw(const Rect &full, const Rect &, bool, int, Colours bg_colour) const override
 	{
-		PixelColour c1 = GetColourGradient(bg_colour, SHADE_DARK);
-		PixelColour c2 = GetColourGradient(bg_colour, SHADE_LIGHTEST);
+		PixelColour c1 = GetColourGradient(bg_colour, Shade::Dark);
+		PixelColour c2 = GetColourGradient(bg_colour, Shade::Lightest);
 
 		int mid = CentreBounds(full.top, full.bottom, 0);
 		GfxFillRect(full.WithY(mid - WidgetDimensions::scaled.bevel.bottom, mid - 1), c1);
diff --git a/src/dropdown_type.h b/src/dropdown_type.h
index a80454701e..dfb5fb73c0 100644
--- a/src/dropdown_type.h
+++ b/src/dropdown_type.h
@@ -76,7 +76,7 @@ public:
 	 */
 	virtual void Draw(const Rect &full, [[maybe_unused]] const Rect &r, [[maybe_unused]] bool sel, [[maybe_unused]] int click_result, Colours bg_colour) const
 	{
-		if (this->masked) GfxFillRect(full, GetColourGradient(bg_colour, SHADE_LIGHT), FillRectMode::Checker);
+		if (this->masked) GfxFillRect(full, GetColourGradient(bg_colour, Shade::Light), FillRectMode::Checker);
 	}
 
 	/**
diff --git a/src/fios_gui.cpp b/src/fios_gui.cpp
index 38f1f97f55..3bdf26d1c3 100644
--- a/src/fios_gui.cpp
+++ b/src/fios_gui.cpp
@@ -573,7 +573,7 @@ public:
 		tr.top += HEADER_HEIGHT;
 
 		/* Create the nice lighter rectangle at the details top */
-		GfxFillRect(r.WithHeight(HEADER_HEIGHT).Shrink(WidgetDimensions::scaled.bevel.left, WidgetDimensions::scaled.bevel.top, WidgetDimensions::scaled.bevel.right, 0), GetColourGradient(Colours::Grey, SHADE_LIGHTEST));
+		GfxFillRect(r.WithHeight(HEADER_HEIGHT).Shrink(WidgetDimensions::scaled.bevel.left, WidgetDimensions::scaled.bevel.top, WidgetDimensions::scaled.bevel.right, 0), GetColourGradient(Colours::Grey, Shade::Lightest));
 		DrawString(hr.left, hr.right, hr.top, STR_SAVELOAD_DETAIL_CAPTION, TC_FROMSTRING, SA_HOR_CENTER);
 
 		if (this->selected == nullptr) return;
diff --git a/src/graph_gui.cpp b/src/graph_gui.cpp
index 82c0cb3d46..9f2c283fff 100644
--- a/src/graph_gui.cpp
+++ b/src/graph_gui.cpp
@@ -725,7 +725,7 @@ public:
 					DrawString(text, str, (this->highlight_state && this->highlight_range == index) ? TC_WHITE : TC_BLACK, SA_CENTER, false, FontSize::Small);
 
 					if (HasBit(this->masked_range, index)) {
-						GfxFillRect(line.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(Colours::Brown, SHADE_DARKER), FillRectMode::Checker);
+						GfxFillRect(line.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(Colours::Brown, Shade::Darker), FillRectMode::Checker);
 					}
 
 					line = line.Translate(0, line_height);
@@ -897,7 +897,7 @@ public:
 			if (c == nullptr) continue;
 
 			DataSet &dataset = this->data.emplace_back();
-			dataset.colour = GetColourGradient(c->colour, SHADE_LIGHTER);
+			dataset.colour = GetColourGradient(c->colour, Shade::Lighter);
 			dataset.exclude_bit = k.base();
 
 			for (int j = this->num_on_x_axis, i = 0; --j >= 0;) {
@@ -1589,8 +1589,8 @@ struct PerformanceRatingDetailWindow : Window {
 		ScoreID score_type = (ScoreID)(widget - WID_PRD_SCORE_FIRST);
 
 		/* The colours used to show how the progress is going */
-		PixelColour colour_done = GetColourGradient(Colours::Green, SHADE_NORMAL);
-		PixelColour colour_notdone = GetColourGradient(Colours::Red, SHADE_NORMAL);
+		PixelColour colour_done = GetColourGradient(Colours::Green, Shade::Normal);
+		PixelColour colour_notdone = GetColourGradient(Colours::Red, Shade::Normal);
 
 		/* Draw all the score parts */
 		int64_t val    = _score_part[company][score_type];
diff --git a/src/group_gui.cpp b/src/group_gui.cpp
index 22ee6ff7c5..4d67f778cc 100644
--- a/src/group_gui.cpp
+++ b/src/group_gui.cpp
@@ -343,7 +343,7 @@ private:
 	{
 		/* Highlight the group if a vehicle is dragged over it */
 		if (g_id == this->group_over) {
-			GfxFillRect(r.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(Colours::Grey, SHADE_LIGHTEST));
+			GfxFillRect(r.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(Colours::Grey, Shade::Lightest));
 		}
 
 		if (g_id == NEW_GROUP) return;
@@ -355,7 +355,7 @@ private:
 
 		const int offset = (rtl ? -(int)this->column_size[VGC_FOLD].width : (int)this->column_size[VGC_FOLD].width) / 2;
 		const int level_width = rtl ? -WidgetDimensions::scaled.hsep_indent : WidgetDimensions::scaled.hsep_indent;
-		const PixelColour linecolour = GetColourGradient(Colours::Orange, SHADE_NORMAL);
+		const PixelColour linecolour = GetColourGradient(Colours::Orange, Shade::Normal);
 
 		r = r.Shrink(WidgetDimensions::scaled.framerect, RectPadding::zero);
 		if (indent > 0) {
@@ -708,7 +708,7 @@ public:
 					for (auto it = first; it != last; ++it) {
 						const Vehicle *v = it->GetSingleVehicle();
 						if (v->group_id != this->vli.ToGroupID()) {
-							GfxFillRect(mr.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(Colours::Grey, SHADE_DARK), FillRectMode::Checker);
+							GfxFillRect(mr.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(Colours::Grey, Shade::Dark), FillRectMode::Checker);
 						}
 						mr = mr.Translate(0, this->resize.step_height);
 					}
diff --git a/src/linkgraph/linkgraph_gui.cpp b/src/linkgraph/linkgraph_gui.cpp
index dc08c6b5a0..ec2b7a999c 100644
--- a/src/linkgraph/linkgraph_gui.cpp
+++ b/src/linkgraph/linkgraph_gui.cpp
@@ -314,7 +314,7 @@ void LinkGraphOverlay::DrawContent(Point pta, Point ptb, const LinkProperties &c
 		GfxDrawLine(pta.x, pta.y + offset_y, ptb.x, ptb.y + offset_y, colour, width, dash);
 	}
 
-	GfxDrawLine(pta.x, pta.y, ptb.x, ptb.y, GetColourGradient(Colours::Grey, SHADE_DARKEST), width);
+	GfxDrawLine(pta.x, pta.y, ptb.x, ptb.y, GetColourGradient(Colours::Grey, Shade::Darkest), width);
 }
 
 /**
@@ -335,8 +335,8 @@ void LinkGraphOverlay::DrawStationDots(const DrawPixelInfo *dpi) const
 
 		LinkGraphOverlay::DrawVertex(pt.x, pt.y, r,
 				GetColourGradient(st->owner != OWNER_NONE ?
-						Company::Get(st->owner)->colour : Colours::Grey, SHADE_LIGHT),
-				GetColourGradient(Colours::Grey, SHADE_DARKEST));
+						Company::Get(st->owner)->colour : Colours::Grey, Shade::Light),
+				GetColourGradient(Colours::Grey, Shade::Darkest));
 	}
 }
 
diff --git a/src/main_gui.cpp b/src/main_gui.cpp
index 73fc413c6e..55488359c4 100644
--- a/src/main_gui.cpp
+++ b/src/main_gui.cpp
@@ -556,8 +556,8 @@ void SetupColoursAndInitialWindow()
 	for (Colours i = Colours::Begin; i != Colours::End; i++) {
 		const uint8_t *b = GetNonSprite(GetColourPalette(i), SpriteType::Recolour) + 1;
 		assert(b != nullptr);
-		for (ColourShade j = SHADE_BEGIN; j < SHADE_END; j++) {
-			SetColourGradient(i, j, PixelColour{b[0xC6 + j]});
+		for (Shade j = Shade::Begin; j < Shade::End; j++) {
+			SetColourGradient(i, j, PixelColour{b[0xC6 + to_underlying(j)]});
 		}
 	}
 
diff --git a/src/misc_gui.cpp b/src/misc_gui.cpp
index 647362c6b6..1f049561eb 100644
--- a/src/misc_gui.cpp
+++ b/src/misc_gui.cpp
@@ -746,7 +746,7 @@ void QueryString::DrawEditBox(const Window *w, WidgetID wid) const
 
 	DrawFrameRect(cr, wi->colour, wi->IsLowered() ? FrameFlag::Lowered : FrameFlags{});
 	DrawSpriteIgnorePadding(rtl ? SPR_IMG_DELETE_RIGHT : SPR_IMG_DELETE_LEFT, PAL_NONE, cr, SA_CENTER);
-	if (this->text.GetText().empty()) GfxFillRect(cr.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(wi->colour, SHADE_DARKER), FillRectMode::Checker);
+	if (this->text.GetText().empty()) GfxFillRect(cr.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(wi->colour, Shade::Darker), FillRectMode::Checker);
 
 	DrawFrameRect(fr, wi->colour, {FrameFlag::Lowered, FrameFlag::Darkened});
 	GfxFillRect(fr.Shrink(WidgetDimensions::scaled.bevel), PC_BLACK);
diff --git a/src/network/network_content_gui.cpp b/src/network/network_content_gui.cpp
index 1c2470c293..e9ad27ade4 100644
--- a/src/network/network_content_gui.cpp
+++ b/src/network/network_content_gui.cpp
@@ -718,7 +718,7 @@ public:
 		tr.top += HEADER_HEIGHT;
 
 		/* Create the nice darker rectangle at the details top */
-		GfxFillRect(r.WithHeight(HEADER_HEIGHT).Shrink(WidgetDimensions::scaled.bevel.left, WidgetDimensions::scaled.bevel.top, WidgetDimensions::scaled.bevel.right, 0), GetColourGradient(Colours::LightBlue, SHADE_NORMAL));
+		GfxFillRect(r.WithHeight(HEADER_HEIGHT).Shrink(WidgetDimensions::scaled.bevel.left, WidgetDimensions::scaled.bevel.top, WidgetDimensions::scaled.bevel.right, 0), GetColourGradient(Colours::LightBlue, Shade::Normal));
 		DrawString(hr.left, hr.right, hr.top, STR_CONTENT_DETAIL_TITLE, TC_FROMSTRING, SA_HOR_CENTER);
 
 		/* Draw the total download size */
diff --git a/src/network/network_gui.cpp b/src/network/network_gui.cpp
index 779c86aa22..7ada2c10f6 100644
--- a/src/network/network_gui.cpp
+++ b/src/network/network_gui.cpp
@@ -647,7 +647,7 @@ public:
 
 		/* Draw the right menu */
 		/* Create the nice darker rectangle at the details top */
-		GfxFillRect(r.WithHeight(header_height).Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(Colours::LightBlue, SHADE_NORMAL));
+		GfxFillRect(r.WithHeight(header_height).Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(Colours::LightBlue, Shade::Normal));
 		hr.top = DrawStringMultiLine(hr, header_msg, TC_FROMSTRING, SA_HOR_CENTER);
 		if (sel == nullptr) return;
 
@@ -1496,7 +1496,7 @@ protected:
 			DrawFrameRect(br, button->colour, {});
 			DrawSpriteIgnorePadding(button->sprite, PAL_NONE, br, SA_CENTER);
 			if (button->disabled) {
-				GfxFillRect(br.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(button->colour, SHADE_DARKER), FillRectMode::Checker);
+				GfxFillRect(br.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(button->colour, Shade::Darker), FillRectMode::Checker);
 			}
 			r = r.Indent(button->width + WidgetDimensions::scaled.hsep_normal, !rtl);
 		}
diff --git a/src/newgrf_gui.cpp b/src/newgrf_gui.cpp
index 9ad832a02d..72b0f715f9 100644
--- a/src/newgrf_gui.cpp
+++ b/src/newgrf_gui.cpp
@@ -907,7 +907,7 @@ struct NewGRFWindow : public Window, NewGRFScanCallback {
 
 			case WID_NS_NEWGRF_INFO_TITLE: {
 				/* Create the nice darker rectangle at the details top. */
-				GfxFillRect(r.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(Colours::Mauve, SHADE_NORMAL));
+				GfxFillRect(r.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(Colours::Mauve, Shade::Normal));
 				DrawString(r.left, r.right, CentreBounds(r.top, r.bottom, GetCharacterHeight(FontSize::Normal)), STR_NEWGRF_SETTINGS_INFO_TITLE, TC_FROMSTRING, SA_HOR_CENTER);
 				break;
 			}
diff --git a/src/order_gui.cpp b/src/order_gui.cpp
index fabd06d163..6e9f0bb5c2 100644
--- a/src/order_gui.cpp
+++ b/src/order_gui.cpp
@@ -1104,7 +1104,7 @@ public:
 					int top = (this->order_over < this->selected_order ? y : y + line_height) - WidgetDimensions::scaled.framerect.top;
 					int bottom = std::min(top + 2, ir.bottom);
 					top = std::max(top - 3, ir.top);
-					GfxFillRect(ir.left, top, ir.right, bottom, GetColourGradient(Colours::Grey, SHADE_LIGHTEST));
+					GfxFillRect(ir.left, top, ir.right, bottom, GetColourGradient(Colours::Grey, Shade::Lightest));
 					break;
 				}
 				y += line_height;
diff --git a/src/palette.cpp b/src/palette.cpp
index 617b0d23ec..0c9c1887f5 100644
--- a/src/palette.cpp
+++ b/src/palette.cpp
@@ -379,7 +379,7 @@ TextColour GetContrastColour(PixelColour background, uint8_t threshold)
  */
 struct ColourGradients
 {
-	using ColourGradient = std::array<PixelColour, SHADE_END>;
+	using ColourGradient = std::array<PixelColour, to_underlying(Shade::End)>;
 
 	static inline std::array<ColourGradient, to_underlying(Colours::End)> gradient{};
 };
@@ -390,9 +390,9 @@ struct ColourGradients
  * @param shade Shade level from 1 to 7.
  * @returns palette index of colour.
  */
-PixelColour GetColourGradient(Colours colour, ColourShade shade)
+PixelColour GetColourGradient(Colours colour, Shade shade)
 {
-	return ColourGradients::gradient[to_underlying(colour) % to_underlying(Colours::End)][shade % SHADE_END];
+	return ColourGradients::gradient[to_underlying(colour) % to_underlying(Colours::End)][to_underlying(shade) % to_underlying(Shade::End)];
 }
 
 /**
@@ -401,9 +401,9 @@ PixelColour GetColourGradient(Colours colour, ColourShade shade)
  * @param shade Shade level from 1 to 7.
  * @param palette_index Palette index to set.
  */
-void SetColourGradient(Colours colour, ColourShade shade, PixelColour palette_index)
+void SetColourGradient(Colours colour, Shade shade, PixelColour palette_index)
 {
 	assert(colour < Colours::End);
-	assert(shade < SHADE_END);
-	ColourGradients::gradient[to_underlying(colour) % to_underlying(Colours::End)][shade % SHADE_END] = palette_index;
+	assert(shade < Shade::End);
+	ColourGradients::gradient[to_underlying(colour) % to_underlying(Colours::End)][to_underlying(shade) % to_underlying(Shade::End)] = palette_index;
 }
diff --git a/src/palette_func.h b/src/palette_func.h
index 89c0f5a61f..5b1ceb0d24 100644
--- a/src/palette_func.h
+++ b/src/palette_func.h
@@ -69,22 +69,24 @@ inline bool IsValidColours(Colours colours)
 
 TextColour GetContrastColour(PixelColour background, uint8_t threshold = 128);
 
-enum ColourShade : uint8_t {
-	SHADE_BEGIN = 0,
-	SHADE_DARKEST = SHADE_BEGIN,
-	SHADE_DARKER,
-	SHADE_DARK,
-	SHADE_NORMAL,
-	SHADE_LIGHT,
-	SHADE_LIGHTER,
-	SHADE_LIGHTEST,
-	SHADE_LIGHTEREST,
-	SHADE_END,
-};
-DECLARE_INCREMENT_DECREMENT_OPERATORS(ColourShade)
+/** The eight shades of each company colour. Not all shaded are used. */
+enum class Shade : uint8_t {
+	Darkest, ///< Darkest colour shade.
+	Darker, ///< Darker colour shade.
+	Dark, ///< Dark colour shade.
+	Normal, ///< Normal colour shade.
+	Light, ///< Light colour shade.
+	Lighter, ///< Lighter colour shade.
+	Lightest, ///< Lightest colour shade.
+	Lighterest, ///< Lighterest colour shade.
 
-PixelColour GetColourGradient(Colours colour, ColourShade shade);
-void SetColourGradient(Colours colour, ColourShade shade, PixelColour palette_colour);
+	End, ///< End marker for iteration.
+	Begin = Shade::Darkest, ///< Begin marker for iteration.
+};
+DECLARE_INCREMENT_DECREMENT_OPERATORS(Shade)
+
+PixelColour GetColourGradient(Colours colour, Shade shade);
+void SetColourGradient(Colours colour, Shade shade, PixelColour palette_colour);
 
 /**
  * Return the colour for a particular greyscale level.
diff --git a/src/picker_gui.cpp b/src/picker_gui.cpp
index e79f27ba94..0efb849a66 100644
--- a/src/picker_gui.cpp
+++ b/src/picker_gui.cpp
@@ -414,7 +414,7 @@ void PickerWindow::DrawWidget(const Rect &r, WidgetID widget) const
 			}
 
 			if (!this->callbacks.IsTypeAvailable(item.class_index, item.index)) {
-				GfxFillRect(ir, GetColourGradient(Colours::Grey, SHADE_DARKER), FillRectMode::Checker);
+				GfxFillRect(ir, GetColourGradient(Colours::Grey, Shade::Darker), FillRectMode::Checker);
 			}
 			break;
 		}
diff --git a/src/settingentry_gui.cpp b/src/settingentry_gui.cpp
index 85f427d40d..7f9c7e706f 100644
--- a/src/settingentry_gui.cpp
+++ b/src/settingentry_gui.cpp
@@ -99,7 +99,7 @@ uint BaseSettingEntry::Draw(GameSettings *settings_ptr, int left, int right, int
 
 	int x = rtl ? right : left;
 	if (cur_row >= first_row) {
-		PixelColour colour = GetColourGradient(Colours::Orange, SHADE_NORMAL);
+		PixelColour colour = GetColourGradient(Colours::Orange, Shade::Normal);
 		y += (cur_row - first_row) * BaseSettingEntry::line_height; // Compute correct y start position
 
 		/* Draw vertical for parent nesting levels */
diff --git a/src/settings_gui.cpp b/src/settings_gui.cpp
index 8d42f27bc2..7de7b2b7fe 100644
--- a/src/settings_gui.cpp
+++ b/src/settings_gui.cpp
@@ -1878,7 +1878,7 @@ void ShowGameOptions()
  */
 void DrawArrowButtons(int x, int y, Colours button_colour, uint8_t state, bool clickable_left, bool clickable_right)
 {
-	PixelColour colour = GetColourGradient(button_colour, SHADE_DARKER);
+	PixelColour colour = GetColourGradient(button_colour, Shade::Darker);
 	Dimension dim = NWidgetScrollbar::GetHorizontalDimension();
 
 	Rect lr = {x,                  y, x + (int)dim.width     - 1, y + (int)dim.height - 1};
@@ -1910,7 +1910,7 @@ void DrawArrowButtons(int x, int y, Colours button_colour, uint8_t state, bool c
  */
 void DrawUpDownButtons(int x, int y, Colours button_colour, uint8_t state, bool clickable_up, bool clickable_down)
 {
-	PixelColour colour = GetColourGradient(button_colour, SHADE_DARKER);
+	PixelColour colour = GetColourGradient(button_colour, Shade::Darker);
 
 	Rect r = {x, y, x + SETTING_BUTTON_WIDTH - 1, y + SETTING_BUTTON_HEIGHT - 1};
 	Rect ur = r.WithWidth(SETTING_BUTTON_WIDTH / 2, (_current_text_dir == TD_RTL));
@@ -1936,7 +1936,7 @@ void DrawUpDownButtons(int x, int y, Colours button_colour, uint8_t state, bool
  */
 void DrawDropDownButton(int x, int y, Colours button_colour, bool state, bool clickable)
 {
-	PixelColour colour = GetColourGradient(button_colour, SHADE_DARKER);
+	PixelColour colour = GetColourGradient(button_colour, Shade::Darker);
 
 	Rect r = {x, y, x + SETTING_BUTTON_WIDTH - 1, y + SETTING_BUTTON_HEIGHT - 1};
 
@@ -1962,13 +1962,13 @@ void DrawBoolButton(int x, int y, Colours button_colour, Colours background, boo
 	Rect r = {x, y, x + SETTING_BUTTON_WIDTH - 1, y + SETTING_BUTTON_HEIGHT - 1};
 	DrawFrameRect(r, state ? Colours::Green : background, state ? FrameFlags{FrameFlag::Lowered} : FrameFlags{FrameFlag::Lowered, FrameFlag::BorderOnly});
 	if (!clickable) {
-		GfxFillRect(r.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(state ? Colours::Green : background, SHADE_DARKER), FillRectMode::Checker);
+		GfxFillRect(r.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(state ? Colours::Green : background, Shade::Darker), FillRectMode::Checker);
 	}
 
 	Rect button_rect = r.WithWidth(SETTING_BUTTON_WIDTH / 3, state ^ (_current_text_dir == TD_RTL));
 	DrawFrameRect(button_rect, button_colour, {});
 	if (!clickable) {
-		GfxFillRect(button_rect.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(button_colour, SHADE_DARKER), FillRectMode::Checker);
+		GfxFillRect(button_rect.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(button_colour, Shade::Darker), FillRectMode::Checker);
 	}
 }
 
diff --git a/src/slider.cpp b/src/slider.cpp
index c82006bb7b..74beed0e1c 100644
--- a/src/slider.cpp
+++ b/src/slider.cpp
@@ -45,9 +45,9 @@ void DrawSliderWidget(Rect r, Colours wedge_colour, Colours handle_colour, TextC
 	int wx1 = r.left  + sw / 2;
 	int wx2 = r.right - sw / 2;
 	if (_current_text_dir == TD_RTL) std::swap(wx1, wx2);
-	const PixelColour shadow = GetColourGradient(wedge_colour, SHADE_DARK);
-	const PixelColour fill = GetColourGradient(wedge_colour, SHADE_LIGHTER);
-	const PixelColour light = GetColourGradient(wedge_colour, SHADE_LIGHTEST);
+	const PixelColour shadow = GetColourGradient(wedge_colour, Shade::Dark);
+	const PixelColour fill = GetColourGradient(wedge_colour, Shade::Lighter);
+	const PixelColour light = GetColourGradient(wedge_colour, Shade::Lightest);
 	const std::array<Point, 3> wedge{ Point{wx1, r.bottom - ha}, Point{wx2, r.top + ha}, Point{wx2, r.bottom - ha} };
 	GfxFillPolygon(wedge, fill);
 	GfxDrawLine(wedge[0].x, wedge[0].y, wedge[2].x, wedge[2].y, light, t);
diff --git a/src/smallmap_gui.cpp b/src/smallmap_gui.cpp
index 11fb15e206..bbe863056b 100644
--- a/src/smallmap_gui.cpp
+++ b/src/smallmap_gui.cpp
@@ -345,7 +345,7 @@ void BuildOwnerLegend()
 
 	int i = NUM_NO_COMPANY_ENTRIES;
 	for (const Company *c : Company::Iterate()) {
-		_legend_land_owners[i].colour = GetColourGradient(c->colour, SHADE_LIGHT);
+		_legend_land_owners[i].colour = GetColourGradient(c->colour, Shade::Light);
 		_legend_land_owners[i].company = c->index;
 		_legend_land_owners[i].show_on_map = true;
 		_legend_land_owners[i].col_break = false;
diff --git a/src/train_gui.cpp b/src/train_gui.cpp
index 06f7d4c458..4b79fd9d67 100644
--- a/src/train_gui.cpp
+++ b/src/train_gui.cpp
@@ -81,7 +81,7 @@ static int HighlightDragPosition(int px, int max_width, int y, VehicleID selecti
 		int top = y - height / 2;
 		Rect r = {drag_hlight_left, top, drag_hlight_right, top + height - 1};
 		/* Sprite-scaling is used here as the area is from sprite size */
-		GfxFillRect(r.Shrink(ScaleSpriteTrad(1)), GetColourGradient(Colours::Grey, SHADE_LIGHTEST));
+		GfxFillRect(r.Shrink(ScaleSpriteTrad(1)), GetColourGradient(Colours::Grey, Shade::Lightest));
 	}
 
 	return drag_hlight_width;
@@ -406,7 +406,7 @@ void DrawTrainDetails(const Train *v, const Rect &r, int vscroll_pos, uint16_t v
 				if (vscroll_pos <= 0 && vscroll_pos > -vscroll_cap) {
 					int py = r.top - line_height * vscroll_pos + text_y_offset;
 					if (i > 0 || separate_sprite_row) {
-						if (vscroll_pos != 0) GfxFillRect(r.WithY(py - WidgetDimensions::scaled.matrix.top - 1, py - WidgetDimensions::scaled.matrix.top), GetColourGradient(Colours::Grey, SHADE_LIGHT));
+						if (vscroll_pos != 0) GfxFillRect(r.WithY(py - WidgetDimensions::scaled.matrix.top - 1, py - WidgetDimensions::scaled.matrix.top), GetColourGradient(Colours::Grey, Shade::Light));
 					}
 					switch (det_tab) {
 						case TDW_TAB_CARGO:
diff --git a/src/vehicle_gui.cpp b/src/vehicle_gui.cpp
index 26525e447e..1a45f27a6e 100644
--- a/src/vehicle_gui.cpp
+++ b/src/vehicle_gui.cpp
@@ -704,7 +704,7 @@ static void DrawVehicleRefitWindow(const RefitOptions &refits, const RefitOption
 	bool rtl = _current_text_dir == TD_RTL;
 	uint iconwidth = std::max(GetSpriteSize(SPR_CIRCLE_FOLDED).width, GetSpriteSize(SPR_CIRCLE_UNFOLDED).width);
 	uint iconheight = GetSpriteSize(SPR_CIRCLE_FOLDED).height;
-	PixelColour linecolour = GetColourGradient(Colours::Orange, SHADE_NORMAL);
+	PixelColour linecolour = GetColourGradient(Colours::Orange, Shade::Normal);
 
 	int iconleft   = rtl ? ir.right - iconwidth     : ir.left;
 	int iconcenter = rtl ? ir.right - iconwidth / 2 : ir.left + iconwidth / 2;
diff --git a/src/viewport.cpp b/src/viewport.cpp
index a582b5493a..4e843274ff 100644
--- a/src/viewport.cpp
+++ b/src/viewport.cpp
@@ -1789,7 +1789,7 @@ static void ViewportDrawStrings(ZoomLevel zoom, const StringSpriteToDrawVector *
 		}
 
 		if (ss.flags.Test(ViewportStringFlag::TextColour)) {
-			if (ss.colour != Colours::Invalid) colour = GetColourGradient(ss.colour, SHADE_LIGHTER).ToTextColour();
+			if (ss.colour != Colours::Invalid) colour = GetColourGradient(ss.colour, Shade::Lighter).ToTextColour();
 		}
 
 		int left = x + WidgetDimensions::scaled.fullbevel.left;
diff --git a/src/widget.cpp b/src/widget.cpp
index 37ee61a685..dbe1f0c19b 100644
--- a/src/widget.cpp
+++ b/src/widget.cpp
@@ -313,10 +313,10 @@ void DrawFrameRect(int left, int top, int right, int bottom, Colours colour, Fra
 	} else {
 		assert(colour < Colours::End);
 
-		const PixelColour dark         = GetColourGradient(colour, SHADE_DARK);
-		const PixelColour medium_dark  = GetColourGradient(colour, SHADE_LIGHT);
-		const PixelColour medium_light = GetColourGradient(colour, SHADE_LIGHTER);
-		const PixelColour light        = GetColourGradient(colour, SHADE_LIGHTEST);
+		const PixelColour dark         = GetColourGradient(colour, Shade::Dark);
+		const PixelColour medium_dark  = GetColourGradient(colour, Shade::Light);
+		const PixelColour medium_light = GetColourGradient(colour, Shade::Lighter);
+		const PixelColour light        = GetColourGradient(colour, Shade::Lightest);
 		PixelColour interior;
 
 		Rect outer = {left, top, right, bottom};                   // Outside rectangle
@@ -480,7 +480,7 @@ static inline void DrawMatrix(const Rect &r, Colours colour, bool clicked, uint3
 		row_height = r.Height() / num_rows;
 	}
 
-	PixelColour col = GetColourGradient(colour, SHADE_LIGHTER);
+	PixelColour col = GetColourGradient(colour, Shade::Lighter);
 
 	int x = r.left;
 	for (int ctr = num_columns; ctr > 1; ctr--) {
@@ -494,7 +494,7 @@ static inline void DrawMatrix(const Rect &r, Colours colour, bool clicked, uint3
 		GfxFillRect(r.left + WidgetDimensions::scaled.bevel.left, x, r.right - WidgetDimensions::scaled.bevel.right, x + WidgetDimensions::scaled.bevel.top - 1, col);
 	}
 
-	col = GetColourGradient(colour, SHADE_NORMAL);
+	col = GetColourGradient(colour, Shade::Normal);
 
 	x = r.left - 1;
 	for (int ctr = num_columns; ctr > 1; ctr--) {
@@ -526,8 +526,8 @@ static inline void DrawVerticalScrollbar(const Rect &r, Colours colour, bool up_
 	DrawImageButtons(r.WithHeight(height, false),  NWID_VSCROLLBAR, colour, up_clicked,   SPR_ARROW_UP,   SA_CENTER);
 	DrawImageButtons(r.WithHeight(height, true),   NWID_VSCROLLBAR, colour, down_clicked, SPR_ARROW_DOWN, SA_CENTER);
 
-	PixelColour c1 = GetColourGradient(colour, SHADE_DARK);
-	PixelColour c2 = GetColourGradient(colour, SHADE_LIGHTEST);
+	PixelColour c1 = GetColourGradient(colour, Shade::Dark);
+	PixelColour c2 = GetColourGradient(colour, Shade::Lightest);
 
 	/* draw "shaded" background */
 	Rect bg = r.Shrink(0, height);
@@ -566,8 +566,8 @@ static inline void DrawHorizontalScrollbar(const Rect &r, Colours colour, bool l
 	DrawImageButtons(r.WithWidth(width, false), NWID_HSCROLLBAR, colour, left_clicked,  SPR_ARROW_LEFT,  SA_CENTER);
 	DrawImageButtons(r.WithWidth(width, true),  NWID_HSCROLLBAR, colour, right_clicked, SPR_ARROW_RIGHT, SA_CENTER);
 
-	PixelColour c1 = GetColourGradient(colour, SHADE_DARK);
-	PixelColour c2 = GetColourGradient(colour, SHADE_LIGHTEST);
+	PixelColour c1 = GetColourGradient(colour, Shade::Dark);
+	PixelColour c2 = GetColourGradient(colour, Shade::Lightest);
 
 	/* draw "shaded" background */
 	Rect bg = r.Shrink(width, 0);
@@ -606,8 +606,8 @@ static inline void DrawFrame(const Rect &r, Colours colour, TextColour text_colo
 
 	if (!str.empty()) x2 = DrawString(r.left + WidgetDimensions::scaled.frametext.left, r.right - WidgetDimensions::scaled.frametext.right, r.top, str, text_colour, align, false, fs);
 
-	PixelColour c1 = GetColourGradient(colour, SHADE_DARK);
-	PixelColour c2 = GetColourGradient(colour, SHADE_LIGHTEST);
+	PixelColour c1 = GetColourGradient(colour, Shade::Dark);
+	PixelColour c2 = GetColourGradient(colour, Shade::Lightest);
 
 	/* If the frame has text, adjust the top bar to fit half-way through */
 	Rect inner = r.Shrink(ScaleGUITrad(1));
@@ -704,7 +704,7 @@ static inline void DrawResizeBox(const Rect &r, Colours colour, bool at_left, bo
 	if (bevel) {
 		DrawFrameRect(r, colour, clicked ? FrameFlag::Lowered : FrameFlags{});
 	} else if (clicked) {
-		GfxFillRect(r.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(colour, SHADE_LIGHTER));
+		GfxFillRect(r.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(colour, Shade::Lighter));
 	}
 	DrawSpriteIgnorePadding(at_left ? SPR_WINDOW_RESIZE_LEFT : SPR_WINDOW_RESIZE_RIGHT, PAL_NONE, r.Shrink(ScaleGUITrad(2)), at_left ? (SA_LEFT | SA_BOTTOM | SA_FORCE) : (SA_RIGHT | SA_BOTTOM | SA_FORCE));
 }
@@ -744,7 +744,7 @@ void DrawCaption(const Rect &r, Colours colour, Owner owner, TextColour text_col
 	DrawFrameRect(ir, colour, company_owned ? FrameFlags{FrameFlag::Lowered, FrameFlag::Darkened, FrameFlag::BorderOnly} : FrameFlags{FrameFlag::Lowered, FrameFlag::Darkened});
 
 	if (company_owned) {
-		GfxFillRect(ir.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(_company_colours[owner], SHADE_NORMAL));
+		GfxFillRect(ir.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(_company_colours[owner], Shade::Normal));
 	}
 
 	if (str.empty()) return;
@@ -2093,7 +2093,7 @@ NWidgetCore *NWidgetMatrix::GetWidgetFromPos(int x, int y)
 /* virtual */ void NWidgetMatrix::Draw(const Window *w)
 {
 	/* Fill the background. */
-	GfxFillRect(this->GetCurrentRect(), GetColourGradient(this->colour, SHADE_LIGHT));
+	GfxFillRect(this->GetCurrentRect(), GetColourGradient(this->colour, Shade::Light));
 
 	/* Set up a clipping area for the previews. */
 	bool rtl = _current_text_dir == TD_RTL;
@@ -2361,7 +2361,7 @@ void NWidgetBackground::Draw(const Window *w)
 	if (this->child != nullptr) this->child->Draw(w);
 
 	if (this->IsDisabled()) {
-		GfxFillRect(r.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(this->colour, SHADE_DARKER), FillRectMode::Checker);
+		GfxFillRect(r.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(this->colour, Shade::Darker), FillRectMode::Checker);
 	}
 
 	DrawOutline(w, this);
@@ -2636,7 +2636,7 @@ void NWidgetScrollbar::Draw(const Window *w)
 	}
 
 	if (this->IsDisabled()) {
-		GfxFillRect(r.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(this->colour, SHADE_DARKER), FillRectMode::Checker);
+		GfxFillRect(r.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(this->colour, Shade::Darker), FillRectMode::Checker);
 	}
 
 	DrawOutline(w, this);
@@ -3126,7 +3126,7 @@ void NWidgetLeaf::Draw(const Window *w)
 
 	if (this->IsDisabled() && this->type != WWT_BOOLBTN) {
 		/* WWT_BOOLBTN is excluded as it draws its own disabled state. */
-		GfxFillRect(r.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(this->colour, SHADE_DARKER), FillRectMode::Checker);
+		GfxFillRect(r.Shrink(WidgetDimensions::scaled.bevel), GetColourGradient(this->colour, Shade::Darker), FillRectMode::Checker);
 	}
 
 	DrawOutline(w, this);