diff --git a/tools/skqp/make_gmkb.go b/tools/skqp/make_gmkb.go
index 97e44e449e..e5dd06ca67 100644
--- a/tools/skqp/make_gmkb.go
+++ b/tools/skqp/make_gmkb.go
@@ -29,6 +29,17 @@ const (
 	max_png = "max.png"
 )
 
+// `slack` is an amount to add to the max and subtract from the minimim channel
+// value for each pixel for the given test.  By default, slack is 0.
+var slack = map[string]int{
+	"imagemagnifier":  1,
+	"xfermodes":       1,
+	"xfermodes2":      1,
+	"xfermodes3":      1,
+	"dashcircle":      1,
+	"encode-srgb-jpg": 1,
+}
+
 type ExportTestRecordArray []search.ExportTestRecord
 
 func (a ExportTestRecordArray) Len() int           { return len(a) }
@@ -44,6 +55,15 @@ func in(v string, a []string) bool {
 	return false
 }
 
+func clampU8(v int) uint8 {
+	if v < 0 {
+		return 0
+	} else if v > 255 {
+		return 255
+	}
+	return uint8(v)
+}
+
 func processTest(testName string, imgUrls []string, output string) error {
 	if strings.ContainsRune(testName, '/') {
 		return nil
@@ -84,6 +104,15 @@ func processTest(testName string, imgUrls []string, output string) error {
 	if img_max.Rect.Max.X == 0 {
 		return nil
 	}
+	if delta, ok := slack[testName]; ok {
+		for i, v := range img_min.Pix {
+			img_min.Pix[i] = clampU8(int(v) - delta)
+		}
+		for i, v := range img_max.Pix {
+			img_max.Pix[i] = clampU8(int(v) + delta)
+		}
+	}
+
 	if err := os.Mkdir(output_directory, os.ModePerm); err != nil && !os.IsExist(err) {
 		return err
 	}