title: "Soft-proof producer" description: "ICC soft-proof simulation — render the input PDF as it would appear under a destination ICC profile, with a ΔE accuracy summary." group: "Reference" order: 14

Soft-proof producer

The soft-proof producer simulates an input PDF under a destination ICC profile and reports an aggregate ΔE summary, so an editor host (artwork-pdf's soft-proof overlay) can show "how far off will this look on that press?" without a hardcopy proof.

Ships as the compile-pdf-soft-proof satellite package. Mounted under /v1/soft-proof when COMPILE_PRODUCER is soft_proof or all. Schema version: SOFT_PROOF_SCHEMA_VERSION = "1.0.0" (owned by the satellite's version.py, re-exported into /v1/contract).

Endpoint

POST /v1/soft-proof/apply

Request — input PDF plus both ICC profiles inline as base64 (no pre-upload step; the profile bytes are hashed into the cache key, so identical requests hit cache):

{
  "input_pdf_b64": "…",
  "source_icc_b64": "…",
  "destination_icc_b64": "…",
  "options": {
    "intent": "relative-colorimetric",
    "black_point_compensation": true,
    "delta_e_formula": "ciede2000"
  }
}

Response:

{
  "output_pdf_b64": "…",
  "pdf_sha256": "…",
  "input_sha256": "…",
  "options_sha256": "…",
  "source_icc_sha256": "…",
  "destination_icc_sha256": "…",
  "cache_key": "…",
  "cache_hit": false,
  "delta_e": { "max": 0.0, "avg": 0.0, "p95": 0.0 },
  "schema_version": "1.0.0",
  "compile_version": "0.7.0"
}

Errors: 400 (malformed / empty base64, with the offending field named), 422 (engine rejected the payload), 500 (post-condition verify failed).

Notes

delta_e carries only max / avg / p95 — the full per-pixel ΔE map is too heavy for the JSON envelope and is rendered separately by the editor host.
Reachable through the streaming wrapper too: POST /v1/stream/apply with producer: "soft_proof" (see stream.md). There is no dedicated CLI subcommand; use compile-pdf stream --producer soft_proof.

Status

Shipped (passthrough engine). The response shape is final; when the real LCMS-based simulator lands, the only caller-visible change is that the ΔE summary becomes meaningfully larger for mismatched profile pairs.