diff --git a/src/ACadSharp.Tests/IO/WriterSingleObjectTests.cs b/src/ACadSharp.Tests/IO/WriterSingleObjectTests.cs
index 0a9e7427..04f54c9b 100644
--- a/src/ACadSharp.Tests/IO/WriterSingleObjectTests.cs
+++ b/src/ACadSharp.Tests/IO/WriterSingleObjectTests.cs
@@ -71,11 +71,26 @@ public void EntityColorTrueColor()
 				this.Document.Entities.Add(c);
 			}
 
+			public void EntityColorByIndex()
+			{
+				Circle c = new Circle();
+				c.Center = new XYZ(0, 0, 0);
+				c.Radius = 10;
+				c.Color = new Color(11);
+
+				this.Document.Entities.Add(c);
+			}
+
 			public void CurrentEntityColorTrueColor()
 			{
 				this.Document.Header.CurrentEntityColor = Color.FromTrueColor(1151726);
 			}
 
+			public void CurrentEntityByIndex()
+			{
+				this.Document.Header.CurrentEntityColor = new Color(11);
+			}
+
 			public void SingleLine()
 			{
 				Line line = new Line(XYZ.Zero, new XYZ(100, 100, 0));
@@ -295,7 +310,9 @@ static WriterSingleObjectTests()
 			Data.Add(new(nameof(SingleCaseGenerator.SingleMLine)));
 			Data.Add(new(nameof(SingleCaseGenerator.EntityColorByLayer)));
 			Data.Add(new(nameof(SingleCaseGenerator.EntityColorTrueColor)));
+			Data.Add(new(nameof(SingleCaseGenerator.EntityColorByIndex)));
 			Data.Add(new(nameof(SingleCaseGenerator.CurrentEntityColorTrueColor)));
+			Data.Add(new(nameof(SingleCaseGenerator.CurrentEntityByIndex)));
 			Data.Add(new(nameof(SingleCaseGenerator.DefaultLayer)));
 			Data.Add(new(nameof(SingleCaseGenerator.LayerTrueColor)));
 			Data.Add(new(nameof(SingleCaseGenerator.SingleMText)));
diff --git a/src/ACadSharp/IO/DWG/DwgStreamWriters/DwgStreamWriterAC18.cs b/src/ACadSharp/IO/DWG/DwgStreamWriters/DwgStreamWriterAC18.cs
index 577052ce..6bde842a 100644
--- a/src/ACadSharp/IO/DWG/DwgStreamWriters/DwgStreamWriterAC18.cs
+++ b/src/ACadSharp/IO/DWG/DwgStreamWriters/DwgStreamWriterAC18.cs
@@ -25,6 +25,11 @@ public override void WriteCmColor(Color value)
 				arr[0] = (byte)value.B;
 				arr[3] = 0b1100_0010;
 			}
+			else if (value.IsByLayer)
+			{
+				arr[3] = 0b11000000;
+				arr[0] = (byte)value.Index;
+			}
 			else
 			{
 				arr[3] = 0b1100_0011;