diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..c561650
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1 @@
+*.icc filter=lfs diff=lfs merge=lfs -text
diff --git a/Dockerfile.alpine b/Dockerfile.alpine
index 225861c..98aa701 100644
--- a/Dockerfile.alpine
+++ b/Dockerfile.alpine
@@ -7,6 +7,7 @@ RUN set -ex; \
       ghostscript \
       inotify-tools \
       make \
+      patch \
     ; \
     \
     tlmgr update --self; \
@@ -20,6 +21,12 @@ RUN set -ex; \
 
 COPY src/usr /usr
 
+RUN set -ex; \
+    \
+    cp /usr/share/ghostscript/lib/PDFA_def.ps /usr/local/share/autodoc/; \
+    patch -d /usr/local/share/autodoc < /usr/local/share/autodoc/PDFA_def.ps.patch; \
+    rm /usr/local/share/autodoc/PDFA_def.ps.patch;
+
 WORKDIR /docs
 ENTRYPOINT ["autodoc"]
 CMD ["-bw"]
@@ -37,7 +44,6 @@ RUN set -ex; \
     apk add --no-cache \
       chromium \
       npm \
-      patch \
     ; \
     \
     npm install --global @mermaid-js/mermaid-cli; \
diff --git a/Dockerfile.ubuntu b/Dockerfile.ubuntu
index d213449..fc89cc0 100644
--- a/Dockerfile.ubuntu
+++ b/Dockerfile.ubuntu
@@ -8,6 +8,7 @@ RUN set -ex; \
       ghostscript \
       inotify-tools \
       make \
+      patch \
     ; rm -rf /var/lib/apt/lists/*; \
     \
     tlmgr update --self; \
@@ -21,6 +22,12 @@ RUN set -ex; \
 
 COPY src/usr /usr
 
+RUN set -ex; \
+    \
+    cp /usr/share/ghostscript/10.02.1/lib/PDFA_def.ps /usr/local/share/autodoc/; \
+    patch -d /usr/local/share/autodoc < /usr/local/share/autodoc/PDFA_def.ps.patch; \
+    rm /usr/local/share/autodoc/PDFA_def.ps.patch;
+
 WORKDIR /docs
 ENTRYPOINT ["autodoc"]
 CMD ["-bw"]
@@ -45,7 +52,6 @@ RUN set -ex; \
       libxkbcommon0 \
       libxrandr2 \
       npm \
-      patch \
     ; rm -rf /var/lib/apt/lists/*; \
     \
     npm install --global @mermaid-js/mermaid-cli; \
diff --git a/src/diagram.lua.patch b/src/diagram.lua.patch
index 3e991d7..acfe7f2 100644
--- a/src/diagram.lua.patch
+++ b/src/diagram.lua.patch
@@ -1,5 +1,5 @@
---- diagram.lua	2024-11-18 23:55:02.673989033 +0100
-+++ diagram.patched.lua	2024-11-19 00:10:14.359878550 +0100
+--- diagram.lua
++++ diagram.lua
 @@ -158,7 +158,7 @@
          write_file(infile, code)
          pipe(
diff --git a/src/usr/local/share/autodoc/PDFA_def.ps.patch b/src/usr/local/share/autodoc/PDFA_def.ps.patch
new file mode 100644
index 0000000..680bb29
--- /dev/null
+++ b/src/usr/local/share/autodoc/PDFA_def.ps.patch
@@ -0,0 +1,11 @@
+--- PDFA_def.ps
++++ PDFA_def.ps
+@@ -9,7 +9,7 @@
+   /DOCINFO pdfmark
+ 
+ % Define an ICC profile :
+-/ICCProfile (srgb.icc) % Customise
++/ICCProfile (/usr/local/share/autodoc/compatibleWithAdobeRGB1998.icc) % Customise
+ def
+ 
+ [/_objdef {icc_PDFA} /type /stream /OBJ pdfmark
diff --git a/src/usr/local/share/autodoc/compatibleWithAdobeRGB1998.icc b/src/usr/local/share/autodoc/compatibleWithAdobeRGB1998.icc
new file mode 100644
index 0000000..1c6795c
--- /dev/null
+++ b/src/usr/local/share/autodoc/compatibleWithAdobeRGB1998.icc
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:76f4ad83ad4726d33e2291a5b3e3bf4f30b2f723c65a583b74a9365e30e097c7
+size 580
diff --git a/src/usr/local/share/autodoc/pdftools.mk b/src/usr/local/share/autodoc/pdftools.mk
new file mode 100644
index 0000000..e30bd0e
--- /dev/null
+++ b/src/usr/local/share/autodoc/pdftools.mk
@@ -0,0 +1,46 @@
+#############
+# FUNCTIONS #
+#############
+
+PDFTOOLS_GSFLAGS := \
+	-sDEVICE=pdfwrite \
+	-dNOOUTERSAVE \
+	-dNOPAUSE \
+	-dQUIET \
+	-dBATCH
+
+pdftools_pdfcat = gs \
+	$(PDFTOOLS_GSFLAGS) \
+	-sPAPERSIZE=a4 \
+	-dFIXEDMEDIA \
+	-dPDFFitPage \
+	-dCompatibilityLevel=1.7 \
+	-dPDFSETTINGS=/ebook \
+	-sOutputFile=$(2) \
+	$(1)
+
+pdftools_mkpdfa = gs \
+	$(PDFTOOLS_GSFLAGS) \
+	-dPDFA=$(1) \
+	-sColorConversionStrategy=RGB \
+	-dPDFACompatibilityPolicy=1 \
+	--permit-file-read=/usr/local/share/autodoc/ \
+	-sOutputFile=$(3) \
+	/opt/pdfa/PDFA_def.ps \
+	$(2)
+
+############
+# PATTERNS #
+############
+
+# convert PDF to PDF/A-2B
+%_pdfa2.pdf: %.pdf
+	$(call convert_pdfa,2,$<,$@)
+
+# convert PDF to PDF/A-3B
+%_pdfa3.pdf: %.pdf
+	$(call convert_pdfa,3,$<,$@)
+
+# convert PDF to PDF/A (default variant 3B)
+%_pdfa.pdf: %.pdf
+	$(call convert_pdfa,3,$<,$@)