Deck owners and automation engineers exporting Keynote to per-slide PNG need one contract: 16:9 widths as integer multiples of the slide grid, one sRGB story, stable file names, and a batch queue that survives overnight runs on a remote Mac mini M4. Below: a 2026 decision matrix, a parameter table, and four README-ready acceptance sections.
Three pain points drive rework: non-integer scaling softens edges; queue contention from parallel Shortcuts or AppleScript jobs skips slides; disk exhaustion on small remote volumes when PNG stacks grow large. Pair this with the social banner PNG export matrix, the AVIF to PNG volume threshold matrix, and the sRGB versus Display P3 checklist for consistent color after Keynote.
Table of Contents
Decision matrix
Use this matrix before you automate. It assigns ownership for width, color, and alpha so engineering and design agree on one path before any script runs.
| Scenario | Recommended path | Risk if ignored |
|---|---|---|
| Web and app UI at 1× and 2× | Per-slide PNG using the width ladder below | Fractional CSS fights the raster grid. |
| Print or PDF-first archival | PDF then rasterize outside Keynote at a fixed DPI | ICC surprises when PDF and PNG mix. |
| Video needs motion | Movie or ProRes, not PNG stacks | Stills explode storage and queue time. |
| Layered marketing stills | PNG with alpha, one background rule per deck | Mixed transparency causes halos. |
Parameter table — copy into handoff as the single line of truth. Treat every row as a binary gate during CI promotion.
| Field | Recommended value | Notes |
|---|---|---|
| Aspect | 16:9 Keynote masters | One aspect ratio per batch folder. |
| Export width (px) | 1920, 2560, 3840 for 16:9 | One ladder per product; friendly to 1× and 2× math. |
| Color | sRGB display profile on the export Mac | Matches typical web and mobile targets. |
| sRGB contract | Embed sRGB downstream or profile-free with a README rule | Avoid double conversion with pngquant or AVIF. |
| File naming | deckId_slideNN_title-slug.png |
Zero-padded NN, ASCII slug, case-sensitive safe sort. |
Export presets
Keynote image export is a contract, not a filter. Fix 16:9 masters, avoid mixed slide sizes, and use PNG only for this pipeline. Lock width to the parameter table so every slide shares one grid—no per-author widths. On the remote Mac use an sRGB display profile and pause Night Shift for color sign-off. For transparency pick one rule per deck: all transparent or all solid keys; mixed folders fail alpha probes.
Batch AppleScript and Shortcuts parameters
Treat automation as a serial queue: one Keynote owner at a time. AppleScript should take deck path, output folder, width px, PNG, and subfolder per deck; log start time, slide count, and Keynote version to JSONL. Shortcuts should pass the deck as a file, build paths with the naming rule, and loop slides without relaunching Keynote each time. Use three retries per slide with backoff on busy errors; exit non-zero on any failure so CI skips partial folders. Never point two shortcuts at the same output directory.
Transparency and anti-aliasing acceptance
For transparency, slides marked transparent in the system must ship with alpha; flat RGB is a fail for those SKUs. At 400 percent in Preview, reject halos on logos and rounded rects—usually nested opacity or shadows on the wrong background. For anti-aliasing, diff text and strokes against a golden slide at the locked width; drift often comes from fractional layout pasted from other apps. Log three gates: alpha when required, no stray opaque fill, text within one px of golden.
Remote M4 batch disk headroom
On a remote Mac mini M4, match disk rules to color rules. Pre-flight: at least 20 GB free on the export volume, or 2× last run’s peak—whichever is larger. During the job, poll df and abort below 10 GB free so logs and swap stay healthy. After success, move PNGs off the boot volume or archive them. Count APFS snapshots and local backups toward used space. Raise thresholds for 4K or heavy motion decks.
sips or ImageMagick geometry); enqueue on M4 with JSONL; gate file count, alpha, and disk floor; promote only passing files to out/; version logs with the deck.
Next steps
The Tech Insights index, MacPng homepage, pricing and nodes, and help center are public pages you can share without logging in—use them to align stakeholders before you rent a dedicated export node.
Pin Keynote export QA to one Apple Silicon node
Rent a remote Mac mini M4, freeze presets and naming, then run overnight PNG batches with disk and color gates that match your README.