How to scan A2 and A1 documents using only an A3 office MFP
An A3 MFP cannot fit an A2 or A1 document on its scanner glass in one pass. The workaround scans the document in overlapping sections, then stitches them together digitally. The process is more work than a true wide format scanner but produces an acceptable result for occasional A2 and A1 work in offices without a dedicated wide format device.
The stitched scan approach
(A3 size)
(A3 size)
The approach divides the source document into rectangular regions, each small enough to fit on the A3 scanner glass. Each region scans separately. The regions overlap by 20 to 30 mm to give material for stitching. After all sections are scanned, image editing software combines them into a single file matching the original document size.
The eight step workflow for A2
Lay the A2 document flat with the top half on the scanner glass
Place the document so the top half (longest dimension) sits on the scanner glass. The bottom half hangs off the edge of the device.
Set scan size to A3 and align the document with the glass corner
The corner registration mark on the glass becomes the reference point for the first scan. Ensure the document edge sits firmly in the corner.
Set resolution to 300 DPI and scan to file
300 DPI captures detail without inflating file size. Scan to a folder or USB stick rather than directly to email; you will need to combine the files in software.
Slide the document so the bottom half now sits on the glass, with 20 to 30 mm overlap
The overlap means the second scan captures a strip of content already in the first scan. The strip gives material for the stitching software to align the two halves.
Scan the second section with identical settings
Same resolution, same colour mode, same scan area. Consistency between the two scans is critical for clean stitching.
Open both scans in stitching software
Photoshop, GIMP, Affinity Photo or Microsoft Image Composite Editor all stitch overlapping images. Photoshop's Photomerge function automates the alignment.
Run the stitching tool
The software detects the overlap zone and aligns the two scans. The result is a single image at A2 size. Crop any uneven edges and save as PDF or JPEG.
Verify the stitched output matches the original
Hold the original document up against the digital file. Confirm the proportions match and no content is missing from the overlap zone.
For A1, the same approach with four sections
A1 documents need four A3 scans to cover the full area (2×2 grid). The overlap requirement doubles: each scan overlaps the adjacent scan on both top/bottom and left/right edges. The stitching software handles four image alignment but takes longer than two image alignment.
Above A1 size, the stitched scan approach becomes impractical. Eight or more sections introduce alignment errors that compound, producing visible seams. For A0 and larger, a dedicated wide format scanner is the right tool.
Settings consistency between sections
| Setting | Why it must match across sections |
|---|---|
| Resolution | Mismatched DPI produces sections of different pixel densities |
| Colour mode | Mixed colour and BW sections cannot stitch cleanly |
| Brightness / contrast | Auto exposure varies between scans; disable and use fixed exposure |
| Skew correction | One section straightened, another not, produces alignment mismatch |
| Output format | Same file type across all sections for stitching software |
When the stitched scan fails
Three common failure modes recur in stitched scans.
Alignment seam visible across the image
Insufficient overlap between sections, or shifts in the document between scans. Re scan with 30 mm overlap minimum, and weight the document during repositioning to prevent shift.
Brightness or colour mismatch at the seam
Auto exposure varied between scans. Lock manual exposure at a fixed value and rescan.
Stitching software cannot align
The overlap zone lacks distinguishing features (large blank area, repeating pattern). Add a small registration mark with a pencil at three points across the overlap zone, scan, and erase afterward.
The dedicated scanner alternative
For architecture, engineering and design studios, a wide format scanner or large format plotter with scan function handles A1 and A0 in a single pass at far higher quality than stitched scans. The investment makes sense at around 20 A1 scans per month or above. Below that volume, the stitched scan approach combined with occasional outsourcing produces acceptable results without the capital cost.
Volume thresholds
The stitched scan approach handles up to roughly 5 A2 or A1 documents per session. Beyond that, the manual repositioning and stitching becomes tedious. The setup time and quality control overhead make this technique a back up rather than a primary workflow.