diff --git a/blocks/duotone-filter/duotone.php b/blocks/duotone-filter/duotone.php
index 68390c77..f04f8331 100644
--- a/blocks/duotone-filter/duotone.php
+++ b/blocks/duotone-filter/duotone.php
@@ -1,35 +1,22 @@
 <?php
 
-if ( ! function_exists( 'hex2rgb' ) ) {
-	function hex2rgb( $color ) {
-		if ( strlen( $color ) === 4 ) {
-			$r = hexdec( substr( $color, 1, 1 ) . substr( $color, 1, 1 ) );
-			$g = hexdec( substr( $color, 2, 1 ) . substr( $color, 2, 1 ) );
-			$b = hexdec( substr( $color, 3, 1 ) . substr( $color, 3, 1 ) );
-		} elseif ( strlen( $color ) === 7 ) {
-			$r = hexdec( substr( $color, 1, 2 ) );
-			$g = hexdec( substr( $color, 3, 2 ) );
-			$b = hexdec( substr( $color, 5, 2 ) );
-		} else {
-			return array();
-		}
-
-		return array(
-			'r' => $r / 0xff,
-			'g' => $g / 0xff,
-			'b' => $b / 0xff,
-		);
-	}
-}
+include_once 'utils.php';
 
 // phpcs:disable
 $duotone_id = $block['attrs']['duotoneId'];
+$duotone_selector = '.wp-block-image.' . $duotone_id . ' img';
 $duotone_dark = hex2rgb( $block['attrs']['duotoneDark'] );
 $duotone_light = hex2rgb( $block['attrs']['duotoneLight'] );
 // phpcs:enable
 
 ?>
 
+<style>
+	<?php echo $duotone_selector; ?> {
+		filter: url( <?php echo '#' . $duotone_id; ?> );
+	}
+</style>
+
 <svg
 	xmlns:xlink="http://www.w3.org/1999/xlink"
 	viewBox="0 0 0 0"
@@ -37,16 +24,16 @@ function hex2rgb( $color ) {
 	height="0"
 	focusable="false"
 	role="none"
-	style="visibility: hidden !important; position: absolute !important; left: -9999px !important; overflow: hidden !important;"
+	style="visibility: hidden; position: absolute; left: -9999px; overflow: hidden;"
 >
 	<defs>
 		<filter id="<?php echo $duotone_id; ?>">
 			<feColorMatrix
 				type="matrix"
 				<?php // phpcs:disable ?>
-				values=".2989 .5870 .1140 0 0
-				        .2989 .5870 .1140 0 0
-				        .2989 .5870 .1140 0 0
+				values=".299 .587 .114 0 0
+				        .299 .587 .114 0 0
+				        .299 .587 .114 0 0
 				        0 0 0 1 0"
 				<?php // phpcs:enable ?>
 			/>
diff --git a/blocks/duotone-filter/index.php b/blocks/duotone-filter/index.php
index fe5dcd7c..718dd00f 100644
--- a/blocks/duotone-filter/index.php
+++ b/blocks/duotone-filter/index.php
@@ -8,16 +8,16 @@
 	] );
 
 	function is_supported_block( $block ) {
-		$supported_blocks = [ 'core/image', 'core/cover' ];
+		$supported_blocks = [ 'core/image' ];
 		return in_array( $block['blockName'], $supported_blocks, true );
 	}
 
 	add_filter( 'render_block', function ( $block_content, $block ) {
 		if (
 			! is_supported_block( $block ) ||
-			! array_key_exists( 'duotoneId', $block['attrs'] ) ||
-			! array_key_exists( 'duotoneDark', $block['attrs'] ) ||
-			! array_key_exists( 'duotoneLight', $block['attrs'] )
+			! isset( $block['attrs']['duotoneId'] ) ||
+			! isset( $block['attrs']['duotoneDark'] ) ||
+			! isset( $block['attrs']['duotoneLight'] )
 		) {
 			return $block_content;
 		}
@@ -26,6 +26,6 @@ function is_supported_block( $block ) {
 		include 'duotone.php';
 		$duotone = ob_get_clean();
 
-		return $duotone . $block_content;
+		return $block_content . $duotone;
 	}, 10, 2 );
 } );
diff --git a/blocks/duotone-filter/src/duotone.js b/blocks/duotone-filter/src/duotone.js
index 7688acfb..16214346 100644
--- a/blocks/duotone-filter/src/duotone.js
+++ b/blocks/duotone-filter/src/duotone.js
@@ -3,76 +3,66 @@
  */
 import { SVG } from '@wordpress/components';
 
-const hex2rgb = ( color = '' ) => {
-	let r = '0';
-	let g = '0';
-	let b = '0';
-
-	if ( color.length === 4 ) {
-		r = '0x' + color[ 1 ] + color[ 1 ];
-		g = '0x' + color[ 2 ] + color[ 2 ];
-		b = '0x' + color[ 3 ] + color[ 3 ];
-	} else if ( color.length === 7 ) {
-		r = '0x' + color[ 1 ] + color[ 2 ];
-		g = '0x' + color[ 3 ] + color[ 4 ];
-		b = '0x' + color[ 5 ] + color[ 6 ];
-	} else {
-		return {};
-	}
-
-	return {
-		r: r / 0xff,
-		g: g / 0xff,
-		b: b / 0xff,
-	};
-};
+/**
+ * Internal dependencies
+ */
+import { hex2rgb } from './utils';
 
-function Duotone( { id: duotoneId, darkColor, lightColor } ) {
+function Duotone( { id: duotoneId, darkColor, lightColor, selector } ) {
 	const duotoneDark = hex2rgb( darkColor );
 	const duotoneLight = hex2rgb( lightColor );
 
+	const stylesheet = `
+${ selector } {
+	filter: url( #${ duotoneId } );
+}
+`;
+
 	return (
-		<SVG
-			xmlnsXlink="http://www.w3.org/1999/xlink"
-			viewBox="0 0 0 0"
-			width="0"
-			height="0"
-			focusable="false"
-			role="none"
-			style={ {
-				visibility: 'hidden',
-				position: 'absolute',
-				left: '-9999px',
-				overflow: 'hidden',
-			} }
-		>
-			<defs>
-				<filter id={ duotoneId }>
-					<feColorMatrix
-						type="matrix"
-						// prettier-ignore
-						values=".2989 .5870 .1140 0 0
-						        .2989 .5870 .1140 0 0
-						        .2989 .5870 .1140 0 0
-						        0 0 0 1 0"
-					/>
-					<feComponentTransfer colorInterpolationFilters="sRGB">
-						<feFuncR
-							type="table"
-							tableValues={ `${ duotoneDark.r } ${ duotoneLight.r }` }
-						/>
-						<feFuncG
-							type="table"
-							tableValues={ `${ duotoneDark.g } ${ duotoneLight.g }` }
-						/>
-						<feFuncB
-							type="table"
-							tableValues={ `${ duotoneDark.b } ${ duotoneLight.b }` }
+		<>
+			<SVG
+				xmlnsXlink="http://www.w3.org/1999/xlink"
+				viewBox="0 0 0 0"
+				width="0"
+				height="0"
+				focusable="false"
+				role="none"
+				style={ {
+					visibility: 'hidden',
+					position: 'absolute',
+					left: '-9999px',
+					overflow: 'hidden',
+				} }
+			>
+				<defs>
+					<filter id={ duotoneId }>
+						<feColorMatrix
+							type="matrix"
+							// prettier-ignore
+							values=".299 .587 .114 0 0
+							        .299 .587 .114 0 0
+							        .299 .587 .114 0 0
+							        0 0 0 1 0"
 						/>
-					</feComponentTransfer>
-				</filter>
-			</defs>
-		</SVG>
+						<feComponentTransfer colorInterpolationFilters="sRGB">
+							<feFuncR
+								type="table"
+								tableValues={ `${ duotoneDark.r } ${ duotoneLight.r }` }
+							/>
+							<feFuncG
+								type="table"
+								tableValues={ `${ duotoneDark.g } ${ duotoneLight.g }` }
+							/>
+							<feFuncB
+								type="table"
+								tableValues={ `${ duotoneDark.b } ${ duotoneLight.b }` }
+							/>
+						</feComponentTransfer>
+					</filter>
+				</defs>
+			</SVG>
+			<style dangerouslySetInnerHTML={ { __html: stylesheet } } />
+		</>
 	);
 }
 
diff --git a/blocks/duotone-filter/src/index.js b/blocks/duotone-filter/src/index.js
index b0b432e5..d3001104 100644
--- a/blocks/duotone-filter/src/index.js
+++ b/blocks/duotone-filter/src/index.js
@@ -1,8 +1,14 @@
+/**
+ * External dependencies
+ */
+import classnames from 'classnames';
+
 /**
  * WordPress dependencies
  */
 import { InspectorControls, PanelColorSettings } from '@wordpress/block-editor';
 import { createHigherOrderComponent, useInstanceId } from '@wordpress/compose';
+import { useSelect } from '@wordpress/data';
 import { useEffect } from '@wordpress/element';
 import { addFilter } from '@wordpress/hooks';
 import { __ } from '@wordpress/i18n';
@@ -11,8 +17,12 @@ import { __ } from '@wordpress/i18n';
  * Internal dependencies
  */
 import Duotone from './duotone';
+import { hex2rgb } from './utils';
 
-const SUPPORTED_BLOCKS = [ 'core/image', 'core/cover' ];
+const FALLBACK_DARK_COLOR = '#000';
+const FALLBACK_LIGHT_COLOR = '#fff';
+
+const SUPPORTED_BLOCKS = [ 'core/image' ];
 
 export const isSupportedBlock = ( blockName ) =>
 	SUPPORTED_BLOCKS.includes( blockName );
@@ -34,9 +44,20 @@ const withDuotoneAttributes = ( settings, blockName ) => {
 	return settings;
 };
 
+/**
+ * Convert a hex color to perceived brightness.
+ *
+ * @param {string} color Hex color
+ * @return {number} Perceived brightness of the color
+ */
+const toBrightness = ( color ) => {
+	const { r, g, b } = hex2rgb( color );
+	return r * 0.299 + g * 0.587 + b * 0.114;
+};
+
 const withDuotoneEditorControls = createHigherOrderComponent(
 	( BlockEdit ) => ( props ) => {
-		const { name: blockName, attributes, setAttributes } = props;
+		const { name: blockName, attributes, setAttributes, clientId } = props;
 
 		if ( ! isSupportedBlock( blockName ) ) {
 			return <BlockEdit { ...props } />;
@@ -50,6 +71,29 @@ const withDuotoneEditorControls = createHigherOrderComponent(
 			} );
 		}, [ instanceId ] );
 
+		const [
+			defaultDarkColor = FALLBACK_DARK_COLOR,
+			defaultLightColor = FALLBACK_LIGHT_COLOR,
+		] = useSelect( ( select ) => {
+			const { colors } = select( 'core/block-editor' ).getSettings();
+			return colors
+				.map( ( { color } ) => ( {
+					color,
+					brightness: toBrightness( color ),
+				} ) )
+				.reduce( ( [ min, max ], current ) => {
+					return [
+						! min || current.brightness < min.brightness
+							? current
+							: min,
+						! max || current.brightness > max.brightness
+							? current
+							: max,
+					];
+				}, [] )
+				.map( ( { color } ) => color );
+		}, [] );
+
 		return (
 			<>
 				<InspectorControls>
@@ -60,38 +104,55 @@ const withDuotoneEditorControls = createHigherOrderComponent(
 							{
 								label: __( 'Dark Color', 'block-experiments' ),
 								value: attributes.duotoneDark,
-								onChange: ( duotoneDark ) =>
-									setAttributes( { duotoneDark } ),
+								onChange: ( duotoneDark ) => {
+									if (
+										duotoneDark &&
+										! attributes.duotoneLight
+									) {
+										setAttributes( {
+											duotoneLight:
+												duotoneDark !==
+												defaultLightColor
+													? defaultLightColor
+													: FALLBACK_LIGHT_COLOR,
+										} );
+									}
+									setAttributes( { duotoneDark } );
+								},
 							},
 							{
 								label: __( 'Light Color', 'block-experiments' ),
 								value: attributes.duotoneLight,
-								onChange: ( duotoneLight ) =>
-									setAttributes( { duotoneLight } ),
+								onChange: ( duotoneLight ) => {
+									if (
+										duotoneLight &&
+										! attributes.duotoneDark
+									) {
+										setAttributes( {
+											duotoneDark:
+												duotoneLight !==
+												defaultDarkColor
+													? defaultDarkColor
+													: FALLBACK_DARK_COLOR,
+										} );
+									}
+									setAttributes( { duotoneLight } );
+								},
 							},
 						] }
 					/>
 				</InspectorControls>
+				<BlockEdit { ...props } />
 				{ attributes.duotoneDark &&
 				attributes.duotoneLight &&
 				attributes.duotoneId ? (
-					<>
-						<Duotone
-							id={ attributes.duotoneId }
-							darkColor={ attributes.duotoneDark }
-							lightColor={ attributes.duotoneLight }
-						/>
-						<div
-							style={ {
-								filter: `url( #${ attributes.duotoneId } )`,
-							} }
-						>
-							<BlockEdit { ...props } />
-						</div>
-					</>
-				) : (
-					<BlockEdit { ...props } />
-				) }
+					<Duotone
+						selector={ `#block-${ clientId } img` }
+						id={ attributes.duotoneId }
+						darkColor={ attributes.duotoneDark }
+						lightColor={ attributes.duotoneLight }
+					/>
+				) : null }
 			</>
 		);
 	},
@@ -108,9 +169,7 @@ function addDuotoneFilterStyle( props, block, attributes ) {
 		return props;
 	}
 
-	const { style = {} } = props;
-
-	return { style: { ...style, filter: `url( #${ attributes.duotoneId } )` } };
+	return { className: classnames( props.className, attributes.duotoneId ) };
 }
 
 export function registerBlock() {
diff --git a/blocks/duotone-filter/src/utils.js b/blocks/duotone-filter/src/utils.js
new file mode 100644
index 00000000..192e2d63
--- /dev/null
+++ b/blocks/duotone-filter/src/utils.js
@@ -0,0 +1,23 @@
+export const hex2rgb = ( color = '' ) => {
+	let r = '0';
+	let g = '0';
+	let b = '0';
+
+	if ( color.length === 4 ) {
+		r = '0x' + color[ 1 ] + color[ 1 ];
+		g = '0x' + color[ 2 ] + color[ 2 ];
+		b = '0x' + color[ 3 ] + color[ 3 ];
+	} else if ( color.length === 7 ) {
+		r = '0x' + color[ 1 ] + color[ 2 ];
+		g = '0x' + color[ 3 ] + color[ 4 ];
+		b = '0x' + color[ 5 ] + color[ 6 ];
+	} else {
+		return {};
+	}
+
+	return {
+		r: r / 0xff,
+		g: g / 0xff,
+		b: b / 0xff,
+	};
+};
diff --git a/blocks/duotone-filter/utils.php b/blocks/duotone-filter/utils.php
new file mode 100644
index 00000000..a2eed832
--- /dev/null
+++ b/blocks/duotone-filter/utils.php
@@ -0,0 +1,23 @@
+<?php
+
+if ( ! function_exists( 'hex2rgb' ) ) {
+	function hex2rgb( $color ) {
+		if ( strlen( $color ) === 4 ) {
+			$r = hexdec( substr( $color, 1, 1 ) . substr( $color, 1, 1 ) );
+			$g = hexdec( substr( $color, 2, 1 ) . substr( $color, 2, 1 ) );
+			$b = hexdec( substr( $color, 3, 1 ) . substr( $color, 3, 1 ) );
+		} elseif ( strlen( $color ) === 7 ) {
+			$r = hexdec( substr( $color, 1, 2 ) );
+			$g = hexdec( substr( $color, 3, 2 ) );
+			$b = hexdec( substr( $color, 5, 2 ) );
+		} else {
+			return array();
+		}
+
+		return array(
+			'r' => $r / 0xff,
+			'g' => $g / 0xff,
+			'b' => $b / 0xff,
+		);
+	}
+}