diff --git a/app/scodoc/sco_trombino.py b/app/scodoc/sco_trombino.py
index e603270be..eb303fda7 100644
--- a/app/scodoc/sco_trombino.py
+++ b/app/scodoc/sco_trombino.py
@@ -28,7 +28,7 @@
 """Photos: trombinoscopes
 """
 
-from io import StringIO
+import io
 from zipfile import ZipFile, BadZipfile
 import reportlab
 from reportlab.lib.units import cm, mm
@@ -221,7 +221,7 @@ def check_local_photos_availability(context, groups_infos, REQUEST, format=""):
 
 def _trombino_zip(context, groups_infos, REQUEST):
     "Send photos as zip archive"
-    data = StringIO()
+    data = io.BytesIO()
     Z = ZipFile(data, "w")
     # assume we have the photos (or the user acknowledged the fact)
     # Archive originals (not reduced) images, in JPEG
@@ -229,7 +229,7 @@ def _trombino_zip(context, groups_infos, REQUEST):
         im_path = sco_photos.photo_pathname(context, t, size="orig")
         if not im_path:
             continue
-        img = open(im_path).read()
+        img = open(im_path, "rb").read()
         code_nip = t["code_nip"]
         if code_nip:
             filename = code_nip + ".jpg"
@@ -337,7 +337,7 @@ def _trombino_pdf(context, groups_infos, REQUEST):
     N_PER_ROW = 5  # XXX should be in ScoDoc preferences
 
     StyleSheet = styles.getSampleStyleSheet()
-    report = StringIO()  # in-memory document, no disk file
+    report = io.BytesIO()  # in-memory document, no disk file
     objects = [
         Paragraph(
             SU("Trombinoscope " + sem["titreannee"] + " " + groups_infos.groups_titles),
@@ -411,7 +411,7 @@ def _listeappel_photos_pdf(context, groups_infos, REQUEST):
     # ROWS_PER_PAGE = 26  # XXX should be in ScoDoc preferences
 
     StyleSheet = styles.getSampleStyleSheet()
-    report = StringIO()  # in-memory document, no disk file
+    report = io.BytesIO()  # in-memory document, no disk file
     objects = [
         Paragraph(
             SU(
diff --git a/app/scodoc/sco_trombino_tours.py b/app/scodoc/sco_trombino_tours.py
index 3e1073ae4..7a7be41f7 100644
--- a/app/scodoc/sco_trombino_tours.py
+++ b/app/scodoc/sco_trombino_tours.py
@@ -30,7 +30,7 @@
    Modification Jérome Billoue,Vincent Grimaud, IUT de Tours, 2017
 """
 
-from io import StringIO
+import io
 
 from reportlab.lib import colors
 from reportlab.lib import pagesizes
@@ -265,7 +265,7 @@ def pdf_trombino_tours(
     # Réduit sur une page
     objects = [KeepInFrame(0, 0, objects, mode="shrink")]
     # Build document
-    report = StringIO()  # in-memory document, no disk file
+    report = io.BytesIO()  # in-memory document, no disk file
     filename = "trombino-%s-%s.pdf" % (DeptName, groups_infos.groups_filename)
     document = BaseDocTemplate(report)
     document.addPageTemplates(
@@ -456,7 +456,7 @@ def pdf_feuille_releve_absences(
     # Réduit sur une page
     objects = [KeepInFrame(0, 0, objects, mode="shrink")]
     # Build document
-    report = StringIO()  # in-memory document, no disk file
+    report = io.BytesIO()  # in-memory document, no disk file
     filename = "absences-%s-%s.pdf" % (DeptName, groups_infos.groups_filename)
     if sco_preferences.get_preference(context, "feuille_releve_abs_taille") == "A3":
         taille = A3