PDF to TIFF using Compression 4 but output is blurry

The JPEG compression artefacts in your document could be producing noise when using the default fast 1-bit conversion algorithm.

In the profiles parameter, please set the following values:

{
  "TIFFCompression": "CCITT4",
  "OneBitConversionAlgorithm": "BayerOrderedDithering"
}