Last Updated on 19.05.2026 by DriverNew
When using multifunction printers (MFPs) and scanners, users often encounter three typical defects: the scanned document ends up smaller than the original A4 format, a continuous line (a vertical streak) appears on the image, and the white background takes on a distinct gray tint.
These issues are not hardware malfunctions and are equally common among devices from most popular brands, including HP (such as the Envy, LaserJet, and OfficeJet series), Canon (Pixma, i-SENSYS), Epson (EcoTank), and Brother.
1. Format Error: Why Does the Scan Turn Out Smaller Than A4?
Cause:
The main reason a digital copy shrinks is a mismatch in regional paper standards within the software settings. By default, many drivers are set to the American Letter format (216 × 279 mm), which is wider but shorter than the European A4 standard (210 × 297 mm). When an A4 document is scanned using a Letter profile, the auto-cropping or “fit to size” function proportionally compresses the image, creating extra margins and reducing the scale.
Solution:
- Open the official scanning application on your computer (for example, HP Smart / HP Scan, Canon IJ Scan Utility, or Epson Scan).
- Before you start scanning, go to the “Settings” or “Advanced Settings” section.
- Locate the “Scan Size” or “Original Size” option and manually change the value from “Letter” to “A4”.
- Disable any automatic compression options, such as “Fit to page”.
2. Appearance of a Vertical Streak on the Scan
Cause:
The appearance and origin of the streak depend on how you scan the document:
- When scanning via the Automatic Document Feeder (ADF): If you place a stack of paper into the upper feeder tray, the document moves past a stationary part of the scanner. A thin vertical line (black, white, or colored) running through the entire page means that a microscopic speck of dust, correction fluid residue, glue from a sticky note, or a fingerprint has gotten onto the scanner’s narrow glass strip. The scanner’s logic interprets this static dot as a solid line along the entire moving sheet.
- When scanning on the main scanner glass (Flatbed): If the document lies motionless on the glass, but the line still appears, this indicates an automatic border recognition error (“smart cropping”) on the software side.
Solution:
- Align the sheet strictly according to the A4 corner alignment mark on the flatbed body if you are scanning manually.
- Thoroughly clean the optics. Take a microfiber cloth or any other lint-free cloth. Lightly dampen it with glass cleaner (do not spray liquid directly onto the device!). Wipe the main flatbed glass, and most importantly, the narrow glass strip on the left which is responsible for the Automatic Document Feeder (ADF), as well as the white backing pad on the lid.
3. Gray Background and Poor Brightness (“Gradient Coating”)
Cause:
A gray tint instead of a clean white background occurs due to an incorrectly selected scan mode or misconfigured exposure calibration. When the device is set to “Photo” mode or scans in the full color spectrum (Color), the sensors try to capture the natural texture of the paper, shadows from minor paper wrinkles, and external light reflections. As a result, a white sheet turns into a dirty gray color.
Solution:
- In the scanning software interface, change the content type from “Photo” to “Document” or “Text”.
- If you only need a plain text document without color elements, select the “Black and White” (or “Monochrome”) scanning mode instead of “Grayscale”. This forces the algorithm to cut off any intermediate shades, making the background perfectly white and the text high-contrast.
- For color documents, go to the manual image settings and increase the “Brightness” level by 10–15% while also slightly bumping up the “Contrast”.
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