Fix the "Background Gray Level Not Suitable" Error — Vietnam Portal

What the "gray level not suitable" rejection means

When applying for a Vietnamese passport online, many applicants get this rejection: "Ảnh chân dung 4x6 không hợp lệ. Lý do: Phông nền có độ xám không phù hợp" — meaning the 4x6 portrait is invalid because the background's gray level is not suitable. It comes from the portal's automated photo checker: your background is not white enough, or not uniform, even if it looks white to the eye.

The official photo standard for online passport applications requires a white background with no shadows. The system measures background brightness — an off-white, cream, or shadowed backdrop, or one lit unevenly from one side, fails the check.

Why a background that "looks white" still fails

• Shadow behind you: standing too close to the wall casts a head-and-shoulder shadow the checker reads as gray.
• One-sided lighting: half the backdrop bright, half dark — non-uniform gray level.
• Ivory or cream walls: they look white but measure below the whiteness threshold.
• Underexposed photo: the whole image is dark, pulling the background into gray territory.
• Over-edited photo: manual brightening leaves blotchy white-and-gray patches.

3 ways to fix the gray-background error

Option 1: Replace the background with AI (fastest)

1. Open the change photo background tool;
2. Upload the rejected portrait;
3. AI cuts out your outline and replaces the entire backdrop with uniform white RGB (255,255,255) — no shadows, no gray zones;
4. Download the new file and resubmit on the portal.

This works even for photos taken against gray walls, cream backdrops, or with shadows — no reshoot needed.

Option 2: Reshoot properly

• Stand 30–50 cm away from the wall so your shadow doesn't land on it;
• Face a window in daylight so light falls evenly on your face and the backdrop;
• Pick the brightest white wall available, or hang a flat white sheet;
• No flash — flash throws a hard shadow behind you.

See the full guide on taking a compliant ID photo at home.

Option 3: Check the other criteria before resubmitting

The checker validates several criteria at once. Before resubmitting, compare your photo against the standard:

Criterion	Requirement
Aspect ratio	4 × 6 (width × height), at least 300 DPI
Background	Uniform white, no shadows
Face	About 75% of the frame, looking straight, both ears visible
Glasses, headwear	No glasses, head uncovered
Recency	Taken within the last 6 months

If you get the "photo size not suitable" error instead, the cause is usually a wrong 4x6 ratio or too few pixels — see the 4x6 photo size in pixels conversion table.

The surest fix: process the photo to standard from the start

At anhthe.io, AI processes your portrait to the exact online-passport standard: uniform white RGB (255,255,255) background, correct face ratio, 300+ DPI. The system also pre-checks the criteria that most often trigger rejections (background, brightness, expression, eye position) before delivering your file — and if a submission is still rejected for photo reasons, we re-process it free of charge.