diff --git a/pdf/contentstream/parser.go b/pdf/contentstream/parser.go
index 3e6b4f46..82aed9d2 100644
--- a/pdf/contentstream/parser.go
+++ b/pdf/contentstream/parser.go
@@ -46,6 +46,7 @@ func (this *ContentStreamParser) Parse() (*ContentStreamOperations, error) {
 			obj, err, isOperand := this.parseObject()
 			if err != nil {
 				if err == io.EOF {
+					// End of data. Successful exit point.
 					return &operations, nil
 				}
 				return &operations, err
@@ -69,9 +70,6 @@ func (this *ContentStreamParser) Parse() (*ContentStreamOperations, error) {
 			operation.Params = append(operation.Params, im)
 		}
 	}
-
-	common.Log.Debug("Operation list: %v\n", operations)
-	return &operations, nil
 }
 
 // Skip over any spaces.  Returns the number of spaces skipped and
diff --git a/pdf/contentstream/processor.go b/pdf/contentstream/processor.go
index 50f0a25a..8b27c234 100644
--- a/pdf/contentstream/processor.go
+++ b/pdf/contentstream/processor.go
@@ -7,7 +7,6 @@ package contentstream
 
 import (
 	"errors"
-	"fmt"
 
 	"github.com/unidoc/unidoc/common"
 	. "github.com/unidoc/unidoc/pdf/core"
@@ -25,10 +24,6 @@ type GraphicsState struct {
 
 type GraphicStateStack []GraphicsState
 
-func (gs *GraphicsState) String() string {
-	return fmt.Sprintf("%+v", gs)
-}
-
 func (gsStack *GraphicStateStack) Push(gs GraphicsState) {
 	*gsStack = append(*gsStack, gs)
 }
diff --git a/pdf/core/parser.go b/pdf/core/parser.go
index abb14ba6..2fca8734 100644
--- a/pdf/core/parser.go
+++ b/pdf/core/parser.go
@@ -570,8 +570,6 @@ func (parser *PdfParser) parseObject() (PdfObject, error) {
 			return nil, errors.New("Object parsing error - unexpected pattern")
 		}
 	}
-
-	return nil, errors.New("Object parsing error - unexpected pattern")
 }
 
 // Reads and parses a PDF dictionary object enclosed with '<<' and '>>'
@@ -657,13 +655,12 @@ func (parser *PdfParser) parsePdfVersion() (int, int, error) {
 	result1 := rePdfVersion.FindStringSubmatch(string(b))
 	if len(result1) < 3 {
 		major, minor, err := parser.seekPdfVersionTopDown()
-		if err == nil {
+		if err != nil {
 			common.Log.Debug("Failed recovery - unable to find version")
 			return 0, 0, err
 		}
 
 		return major, minor, nil
-		return 0, 0, errors.New("PDF version not found")
 	}
 
 	majorVersion, err := strconv.ParseInt(result1[1], 10, 64)
diff --git a/pdf/core/parser_test.go b/pdf/core/parser_test.go
index 7b27f956..c3d47048 100644
--- a/pdf/core/parser_test.go
+++ b/pdf/core/parser_test.go
@@ -151,7 +151,7 @@ func TestBoolParsing(t *testing.T) {
 			return
 		}
 		if bool(val) != expected {
-			t.Errorf("bool not as expected (%b)", val)
+			t.Errorf("bool not as expected (got %t, expected %t)", bool(val), expected)
 			return
 		}
 	}
@@ -188,7 +188,7 @@ func TestNumericParsing1(t *testing.T) {
 			return
 		}
 		if float32(*num) != val {
-			t.Errorf("Idx %d, value incorrect (%f)", idx)
+			t.Errorf("Idx %d, value incorrect (%f)", idx, val)
 		}
 	}
 
@@ -230,7 +230,7 @@ func TestNumericParsing2(t *testing.T) {
 			return
 		}
 		if float32(*num) != val {
-			t.Errorf("Idx %d, value incorrect (%f)", idx)
+			t.Errorf("Idx %d, value incorrect (%f)", idx, val)
 		}
 	}
 }
@@ -265,7 +265,7 @@ func TestNumericParsing3(t *testing.T) {
 			return
 		}
 		if float32(*num) != val {
-			t.Errorf("Idx %d, value incorrect (%f)", idx)
+			t.Errorf("Idx %d, value incorrect (%f)", idx, val)
 		}
 	}
 }
diff --git a/pdf/model/image.go b/pdf/model/image.go
index 03fe72aa..48e09ba2 100644
--- a/pdf/model/image.go
+++ b/pdf/model/image.go
@@ -124,7 +124,7 @@ func (this *Image) ToGoImage() (goimage.Image, error) {
 				b := uint16(samples[i+4])<<8 | uint16(samples[i+5])
 				a := uint16(0)
 				if this.alphaData != nil && len(this.alphaData) > aidx+1 {
-					a = uint16(this.alphaData[aidx]<<8) | uint16(this.alphaData[aidx+1])
+					a = (uint16(this.alphaData[aidx]) << 8) | uint16(this.alphaData[aidx+1])
 					aidx += 2
 				}
 				c = gocolor.RGBA64{R: r, G: g, B: b, A: a}