diff --git a/colorm.go b/colorm.go
index f6effe0c6..d4bcbfcc4 100644
--- a/colorm.go
+++ b/colorm.go
@@ -46,7 +46,7 @@ func (c *ColorM) affineColorM() affine.ColorM {
 
 // String returns a string representation of ColorM.
 func (c *ColorM) String() string {
-	return affine.ColorMString(c.affineColorM())
+	return c.affineColorM().String()
 }
 
 // Reset resets the ColorM as identity.
diff --git a/internal/affine/colorm.go b/internal/affine/colorm.go
index 01f888477..0851dd1ff 100644
--- a/internal/affine/colorm.go
+++ b/internal/affine/colorm.go
@@ -42,6 +42,8 @@ var (
 // Before applying a matrix, a color is un-multiplied, and after applying the matrix,
 // the color is multiplied again.
 type ColorM interface {
+	String() string
+
 	IsIdentity() bool
 	ScaleOnly() bool
 	At(i, j int) float32
@@ -71,7 +73,7 @@ type ColorM interface {
 	scaleElements() (r, g, b, a float32)
 }
 
-func ColorMString(c ColorM) string {
+func colorMString(c ColorM) string {
 	var b [16]float32
 	var t [4]float32
 	c.Elements(&b, &t)
@@ -93,6 +95,18 @@ type colorMImplBodyTranslate struct {
 	translate [4]float32
 }
 
+func (c ColorMIdentity) String() string {
+	return "Identity[]"
+}
+
+func (c colorMImplScale) String() string {
+	return fmt.Sprintf("Scale[%f, %f, %f, %f]", c.scale[0], c.scale[1], c.scale[2], c.scale[3])
+}
+
+func (c *colorMImplBodyTranslate) String() string {
+	return colorMString(c)
+}
+
 func clamp(x float32) float32 {
 	if x > 1 {
 		return 1
diff --git a/internal/graphicscommand/command.go b/internal/graphicscommand/command.go
index f55afac1f..6d422bfa0 100644
--- a/internal/graphicscommand/command.go
+++ b/internal/graphicscommand/command.go
@@ -381,7 +381,7 @@ func (c *drawTrianglesCommand) String() string {
 
 	r := fmt.Sprintf("(x:%d, y:%d, width:%d, height:%d)",
 		int(c.dstRegion.X), int(c.dstRegion.Y), int(c.dstRegion.Width), int(c.dstRegion.Height))
-	return fmt.Sprintf("draw-triangles: dst: %s <- src: [%s], dst region: %s, num of indices: %d, colorm: %v, mode: %s, filter: %s, address: %s, even-odd: %t", dst, strings.Join(srcstrs[:], ", "), r, c.nindices, c.color, mode, filter, address, c.evenOdd)
+	return fmt.Sprintf("draw-triangles: dst: %s <- src: [%s], dst region: %s, num of indices: %d, colorm: %s, mode: %s, filter: %s, address: %s, even-odd: %t", dst, strings.Join(srcstrs[:], ", "), r, c.nindices, c.color, mode, filter, address, c.evenOdd)
 }
 
 // Exec executes the drawTrianglesCommand.