---
title: "Runway (Runway Dev API) Ruby ACEScg sequences are now referenced to the source: 2026-09-12 | Harbyn"
description: "Runway (Runway Dev API) Ruby ACEScg sequences are now referenced to the source, announced Sep 12, 2026."
canonical: "https://harbyn.com/changes/runway/2026-09-12-ruby-acescg-sequences-are-now-referenced-to-the-source"
last-updated: 2026-10-02
---

# Runway (Runway Dev API) Ruby ACEScg sequences are now referenced to the source

Markdown version of <https://harbyn.com/changes/runway/2026-09-12-ruby-acescg-sequences-are-now-referenced-to-the-source>.

Behavior change - Runway (Runway Dev API). medium severity. In effect.

The ACEScg sequence outputs are now built from the source plate with recovered highlights, changing their SDR and HDR appearance. The colorimetry.json sidecar now records the construction as plate-referenced. Gen-4.5 ACEScg outputs are unchanged.

## Facts

| Fact | Value |
| --- | --- |
| Vendor | [Runway (Runway Dev API)](https://harbyn.com/vendors/runway.md) |
| Kind | Behavior change |
| Severity | medium |
| Status | In effect |
| Announced | Sep 12, 2026 |
| Added to Harbyn | Oct 2, 2026 |
| Lead time | No dated deadline |
| Symbols | `hdr_exr_acescg_sequence_1_3`, `hdr_exr_acescg_sequence_2_0` |
| Review | Reviewed by a person, extracted by a model |

## Find it in your code

```sh
npx harbyn scan
```

This change names no identifier the scanner can match line by line, so the scan tells you whether your repository uses Runway (Runway Dev API), from its packages and API hosts. Nothing leaves your machine.

## Sources

Where this event comes from: the page we read, when we read it, and the hash of that snapshot.

- <https://docs.dev.runwayml.com/api-details/api_changelog.md> (changelog, fetched 2026-10-02 22:20 UTC, sha256 `ad20c1e9353f74a167dfb12692d8212f5cdf01dd25df96db51e00b716c76d5b7`)

## Related changes

### More from Runway (Runway Dev API)

- [Alpha channel support on /v1/video\_to\_hdr](https://harbyn.com/changes/runway/2026-09-11-alpha-channel-support-on-v1-video-to-hdr.md) (Behavior change, announced Sep 11, 2026)

### Changes at other vendors

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- [Jira / Atlassian Cloud: New IP address ranges in use from January 1, 2027](https://harbyn.com/changes/atlassian-jira/2026-10-16-atlassian-cloud-adds-new-ip-address-ranges.md) (effective Jan 1, 2027)

[All upcoming deadlines](https://harbyn.com/deadlines.md)