diff --git a/backend/dmatrix.c b/backend/dmatrix.c
index 871b3b21..4c767da8 100644
--- a/backend/dmatrix.c
+++ b/backend/dmatrix.c
@@ -588,14 +588,14 @@ static int dm200encode(struct zint_symbol *symbol, const unsigned char source[],
         if (symbol->eci <= 126) {
             target[tp] = (unsigned char) symbol->eci + 1;
             tp++;
-            strcat(binary, " ");
+            strcat(binary, "  ");
         }
         if ((symbol->eci >= 127) && (symbol->eci <= 16382)) {
             target[tp] = (unsigned char) ((symbol->eci - 127) / 254) + 128;
             tp++;
             target[tp] = (unsigned char) ((symbol->eci - 127) % 254) + 1;
             tp++;
-            strcat(binary, "  ");
+            strcat(binary, "   ");
         }
         if (symbol->eci >= 16383) {
             target[tp] = (unsigned char) ((symbol->eci - 16383) / 64516) + 192;
@@ -604,7 +604,7 @@ static int dm200encode(struct zint_symbol *symbol, const unsigned char source[],
             tp++;
             target[tp] = (unsigned char) ((symbol->eci - 16383) % 254) + 1;
             tp++;
-            strcat(binary, "   ");
+            strcat(binary, "    ");
         }
         if (debug) printf("ECI %d ", symbol->eci + 1);
     }