AI Colorization

Convert black-and-white or grayscale photos to full color using AI (DDColor model with OpenCV DNN fallback).

API Endpoint

POST /api/v1/tools/colorize

Processing: Asynchronous (returns 202, poll /api/v1/jobs/{jobId}/progress for status via SSE)

Model bundle: object-eraser-colorize (1-2 GB)

Parameters

Parameter	Type	Required	Default	Description
file	file	Yes	-	Image file (multipart)
intensity	number	No	1.0	Color intensity (0-1). Lower values produce more subtle colorization
model	string	No	"auto"	Model to use: auto, ddcolor, opencv

Example Request

curl -X POST http://localhost:13490/api/v1/tools/colorize \
  -F "[email protected]" \
  -F 'settings={"intensity":0.9,"model":"auto"}'

Response

Initial Response (202 Accepted)

{
  "jobId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
  "async": true
}

Progress (SSE at /api/v1/jobs/{jobId}/progress)

event: progress
data: {"phase":"processing","stage":"Colorizing...","percent":55}

Final Result (via SSE)

{
  "phase": "complete",
  "percent": 100,
  "result": {
    "jobId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
    "downloadUrl": "/api/v1/download/{jobId}/old-bw-photo_colorized.jpg",
    "previewUrl": "/api/v1/download/{jobId}/preview.webp",
    "originalSize": 180000,
    "processedSize": 210000,
    "width": 1920,
    "height": 1080,
    "method": "ddcolor"
  }
}

Notes

• Requires the object-eraser-colorize model bundle to be installed (1-2 GB).
• DDColor produces higher quality results but is slower; OpenCV DNN is faster with slightly lower quality. auto uses DDColor when available with OpenCV fallback.
• The intensity parameter blends between the original grayscale and the AI-colorized result. Use 1.0 for full color, lower values for a partially desaturated vintage look.
• Output format matches the input format automatically.
• For non-browser-previewable output formats, a WebP preview is generated alongside the main output.
• Supports HEIC/HEIF, RAW, TGA, PSD, EXR, and HDR input formats via automatic decoding.