diff --git a/autotests/read/psd/53alphas.png b/autotests/read/psd/53alphas.png
new file mode 100644
index 0000000..3987b5e
Binary files /dev/null and b/autotests/read/psd/53alphas.png differ
diff --git a/autotests/read/psd/53alphas.psd b/autotests/read/psd/53alphas.psd
new file mode 100644
index 0000000..8aa90a4
Binary files /dev/null and b/autotests/read/psd/53alphas.psd differ
diff --git a/src/imageformats/psd.cpp b/src/imageformats/psd.cpp
index 7447fa1..80a61b2 100644
--- a/src/imageformats/psd.cpp
+++ b/src/imageformats/psd.cpp
@@ -643,7 +643,9 @@ static bool IsValid(const PSDHeader &header)
         qDebug() << "PSD header: invalid color mode" << header.color_mode;
         return false;
     }
-    if (header.channel_count < 1 || header.channel_count > 56) {
+    // Specs tells: "Supported range is 1 to 56" but the limit is 57:
+    // Photoshop does not make you add more (see also 53alphas.psd test case).
+    if (header.channel_count < 1 || header.channel_count > 57) {
         qDebug() << "PSD header: invalid number of channels" << header.channel_count;
         return false;
     }