diff --git a/crates/eps/src/import/ai/mod.rs b/crates/eps/src/import/ai/mod.rs
index 449eb73c0..d74fba703 100644
--- a/crates/eps/src/import/ai/mod.rs
+++ b/crates/eps/src/import/ai/mod.rs
@@ -38,8 +38,10 @@ pub(crate) use read::{slot_frame, slot_of};
 #[cfg(test)]
 mod tests;
 
-/// Largest editing data read, decompressed (bytes).
-pub const MAX_DATA: u64 = 256 << 20;
+/// Largest editing data read, decompressed (bytes). Files with embedded rasters reach 340 MB (a
+/// 30 MB poker box template unpacks to 322 MiB), so 64-bit builds read twice the old 256 MiB; a
+/// 32-bit address space (wasm) keeps it.
+pub const MAX_DATA: u64 = if cfg!(target_pointer_width = "64") { 512 << 20 } else { 256 << 20 };
 /// Largest Zstandard window accepted (a frame asking for more is damaged data).
 const MAX_ZSTD_WINDOW: u64 = 64 << 20;
 /// Most Zstandard frames read (the app writes one).
diff --git a/crates/eps/src/import/ai/tests.rs b/crates/eps/src/import/ai/tests.rs
index 3d90a4323..6a0d914c5 100644
--- a/crates/eps/src/import/ai/tests.rs
+++ b/crates/eps/src/import/ai/tests.rs
@@ -1193,6 +1193,22 @@ fn a_linked_images_colour_space_operator_is_ignored() {
     assert_eq!(art(&read_ok(&layer(&art_)).doc).len(), 1);
 }
 
+/// Editing data past the old 256 MiB limit still opens on a 64-bit build (#3510): a card file with
+/// embedded rasters unpacks to over 300 MiB.
+#[cfg(target_pointer_width = "64")]
+#[test]
+fn editing_data_past_256_mib_is_read() {
+    let mut body = stream(&layer("")).into_bytes();
+    // Comment lines the reader skips, so the data stays valid while it grows past the old limit.
+    let filler = vec![b'%'; (257 << 20) - body.len()];
+    body.extend_from_slice(&filler);
+    let raw = [&b"%AI12_CompressedData"[..], &crate::ps::deflate(&body)].concat();
+    assert!(raw.len() < 1 << 20, "zeros compress");
+    let data = decode_private(&raw).unwrap();
+    assert_eq!(data.len(), body.len());
+    assert!(too_large().contains("512 MB"));
+}
+
 #[test]
 fn many_zstandard_frames_are_read_in_one_pass_and_capped() {
     let frame = zstd(b" ");
diff --git a/docs/file-format-parity.md b/docs/file-format-parity.md
index f2eea9f27..91f785528 100644
--- a/docs/file-format-parity.md
+++ b/docs/file-format-parity.md
@@ -130,6 +130,7 @@ the app's own editing copy of a file (an EPS after its `%%EOF`, a `.ai`'s `AIPri
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-25 | minor | `.ai` import: the editing data is read up to 512 MiB on 64-bit builds (the limit was 256 MiB), so a file whose embedded rasters unpack to 300 MiB or more keeps its layers, groups and text instead of opening as its PDF part (part of #3510); 32-bit and web builds keep 256 MiB. Own-fixture test `import::ai::tests::editing_data_past_256_mib_is_read`; scores and hours unchanged |
 | 2026-10-25 | minor | `.ai` import: the `--` placeholder of a radial gradient's highlight (`-- -- angle length Bh`, a gradient without one) and the `XC` operator after a linked image's file name no longer send the whole file to its PDF part, so files with them keep their layers, groups and live text (#4176). A `--` anywhere else is still an operator the reader doesn't know. Own-fixture tests in `import::ai::tests`; scores and hours unchanged |
 | 2026-10-24 | minor | EPS, EMF/WMF and legacy `.ai`: type with ruby (ふりがな) is written with the reading's glyphs where the canvas draws them (they were dropped); legacy `.ai` writes such type as outlines, since a text object can't hold ruby. Tests `eps::tests::ruby_is_written_with_its_type`, `tests_legacy_ai::type_with_ruby_is_outlines_with_the_reading`, `metafile::tests::ruby_is_written_with_its_type`; scores and hours unchanged |
 | 2026-10-24 | minor | `.ai` import: an image larger than the editing data's reader takes (2^25 pixels, a halftone texture at print resolution) no longer leaves its layer blank: the file comes in as its PDF part, which reads larger images, with a note saying why (#1479). Own-fixture test; scores and hours unchanged |