printserver/openspec/changes/revert-colour-mode-default/proposal.md

Proposal

Why

Commit tpypxmkn changed the vendor PPD default *DefaultBRColorMode: Normal → None on the theory that the printer's own CIE conversion washes out colours, and the spec recorded the result as Requirement: Colour output is saturated by default. A controlled before/after comparison now shows the change had no visible effect: prints made after it look the same as prints made before it, and both are clearly less saturated than the same document printed through the Mac's local driver. The commit itself had already noted that a second candidate (VividNoCIE) produced no difference from None; the new comparison extends that to None vs. the vendor default Normal. The washout originates in the server-side PostScript path, not in the printer's UseCIEColor switch — so the README and the spec currently promise a fix that does not exist, and the PPD carries a "modified by this repo" deviation for no measurable benefit.

What Changes

• PPD (assets/Brother HL-4150CDN/ppd/BR4150_2.PPD): restore the vendor default *DefaultBRColorMode: Normal and remove the comment block that justified the None deviation. The six APPrinterPreset entries stay — they are a separate feature and unaffected by this finding.
• README: correct all three places that repeat the claim — the options table (Normal is the default again), Changes to the vendor PPD (only the presets remain a deviation), and the troubleshooting section Colours are printed pale / washed out, rewritten from "fixed via UseCIEColor off" to a documented, tested limitation: BRColorMode/UseCIEColor settings do not measurably change saturation; for colour-critical output use the local driver.
• Spec (printserver/cups): remove Requirement: Colour output is saturated by default (its claim is disproven) and add a requirement that the queue preserves the vendor PPD colour-mode default unless explicitly overridden — encoding the revert and preventing another untested deviation.

Capabilities

New Capabilities

(none)

Modified Capabilities

• printserver/cups: the requirement Colour output is saturated by default is removed and replaced by a requirement that the vendor PPD colour-mode default is preserved.

Impact

• assets/Brother HL-4150CDN/ppd/BR4150_2.PPD — one value line plus its comment restored to the vendor original.
• README.md — three sections (options table, vendor-PPD section, colours troubleshooting).
• openspec/specs/printserver/cups/spec.md — one requirement removed, one added (applied at archive time).
• Runtime behaviour: only the queue's BRColorMode default changes back (None → Normal); per-job/per-queue overrides via PRINTER_OPTIONS or -o are untouched, as are the presets and PRINTER_OPTIONS itself. No container, entrypoint or discovery changes. Since the two defaults print identically, no user-visible difference is expected from the revert either.