Privacy Policy
Last Updated: June 11, 2026
Scope and Acceptance
This Privacy Policy ("Policy") governs the handling of information in connection with the mobile application "Metamer" (the "App"), operated by Chunhou Li ("we," "us," or "our"). By installing, accessing, or using the App, you ("User" or "you") acknowledge that you have read, understood, and agree to be bound by this Policy. If you do not agree to this Policy, you must not use the App.
This Policy is published in English and Simplified Chinese. If the two versions diverge, the English version prevails.
Data Controller and Key Principle
The data controller in respect of any personal data processed in connection with the App is Chunhou Li. Correspondence may be sent to: diveintothefog@gmail.com.
The App has no network features. We do not operate any servers, do not require an account, do not use analytics or advertising SDKs, and do not collect, receive, store, or transmit any User data. All processing described in this Policy happens entirely on your device. The App's App Store privacy label is "Data Not Collected."
1. Data Processed on Your Device
1.1 Camera Frames
When you use the live camera, frames from the device camera are processed in real time, in memory, to apply the selected color-vision filter and to name the color under the reticle. Frames are displayed on screen and then discarded. The freeze-frame feature holds the most recent frame in memory only while the view is frozen. Camera frames are never written to disk and never leave your device unless you explicitly capture a photo (see Section 1.2).
1.2 Photos You Capture, Pick, or Export
- Captured photos: When you tap the shutter, the filtered photo is saved to your photo library, with your permission (see Section 3). Nothing is saved without your action.
- Picked photos: The gallery feature uses the system photo picker, which runs outside the App's process. The App receives only the image you select; it has no access to the rest of your photo library.
- Exports: Filtered photos can be shared as JPEG, HEIC, or match-source files to a destination you choose. The original photo's EXIF metadata is preserved, and a short annotation is added to the EXIF UserComment field recording which Metamer filter was applied. Exported files exist only in the locations you put them.
1.3 Settings and Quick-Check Results
The App stores your preferences locally on your device: selected filter and per-filter severity values, export format, language, the "Speak color names" toggle, and the outcome of the optional color-vision quick check (which axes were flagged and the suggested starting filter). These values never leave your device. The App does not use iCloud; nothing is synced anywhere.
1.4 Generated Ishihara Plates
Ishihara test plates are generated entirely on your device. Exported PNG and PDF files embed the plate's parameters (CVD type, hidden glyph, difficulty) as file metadata so a plate can be identified later. Exported plates exist only in the locations you put them.
1.5 Speech Output
The optional "Speak color names" feature uses on-device speech synthesis. No audio or text is transmitted anywhere.
2. Data Not Collected
We do not collect, and the App is not designed to collect:
- Personal identification information (name, email, physical address), except where voluntarily provided by you when contacting us for support.
- Location data of any kind.
- Photos, camera frames, or any media content.
- Health data. The quick-check outcome described in Section 1.3 stays on your device and is never transmitted.
- Usage analytics, crash reports through third-party services, advertising identifiers, or tracking data of any kind.
- Payment or financial information (the App does not process payments).
The one exception is support correspondence. If you choose to email us, we receive your email address and the contents of your message. We use them solely to respond to you, share them with no one, and retain them no longer than needed to resolve your request. To the extent the EU/UK General Data Protection Regulation applies to this processing, its legal basis is our legitimate interest in responding to your inquiry (Art. 6(1)(f) GDPR). We do not carry out any automated decision-making or profiling.
3. System Permissions
- Camera: Required for the live camera feature, to apply color-vision filters to what you see in real time. No images leave your device. The gallery and Ishihara generator work without camera access.
- Add to Photo Library: Requested only when you save a filtered photo. This is the add-only permission: the App can save the photo you just took, and cannot read, browse, or modify your existing library.
The App requests no other permissions: no location, no microphone, no contacts, no notifications.
4. Storage and Security
All App data (settings, quick-check outcome) is stored locally on your device using iOS storage mechanisms and is protected by your device's security (passcode, Face ID / Touch ID, device encryption). Photos you save are stored in your photo library under the protections iOS affords it. Deleting the App removes all App-stored data; photos and plates you exported remain wherever you saved them, under your control.
We ourselves retain no User data. The only information we may hold is support correspondence you have sent us, handled as described in Section 2.
5. Third-Party Services and External Links
The App integrates no third-party services. There are no analytics, advertising, or crash-reporting SDKs, and the App makes no network requests.
- App Store: Distribution and updates of the App are handled by Apple Inc. Apple may collect information (e.g., iOS version, device model) in accordance with its own policies. Apple's Privacy Policy is available at: https://www.apple.com/privacy/.
- External links: The App or this website may link to third-party resources (e.g., scientific references). Accessing such links takes you outside the App; the privacy practices of those third parties apply.
6. Not a Medical Device
The App is an educational and accessibility tool. The optional color-vision quick check and the Ishihara plate generator are informational only; they are not a medical examination, diagnosis, or treatment, and they must not be relied upon as such. On-screen and printed colors depend on display calibration, print quality, and ambient lighting, which can materially affect results. If you suspect a color vision deficiency or any vision problem, consult a qualified eye-care professional.
7. Disclosure of Personal Data
We do not sell, rent, trade, or disclose personal data, because we do not have any. All User data remains on your device. Should we ever be required by applicable law or valid legal process to disclose information, we would have no User data to disclose unless you have voluntarily provided it to us (e.g., in a support email).
8. Your Rights and Choices
8.1 Access, Correction, Deletion, and Portability
Because all data lives on your device, you exercise these rights directly:
- Access and rectification: View and change all settings within the App at any time.
- Erasure: Re-run or reset the quick check, change any setting, or uninstall the App to remove all App-stored data.
- Portability: Photos and plates you export are standard JPEG, HEIC, PNG, and PDF files that you already hold.
8.2 California Privacy Rights (CCPA/CPRA)
If you are a California resident: we do not collect, use, disclose, sell, or share your personal information, and have not done so in the preceding 12 months, so there are no categories of personal information for us to disclose or delete and nothing to opt out of. You will not be discriminated against for exercising privacy rights. For questions, contact us using the details in Section 12.
8.3 EEA and UK Rights (GDPR)
If you are in the European Economic Area or the United Kingdom: we do not process your personal data on any system under our control (other than support correspondence, see Section 2), so the GDPR rights of access, rectification, erasure, restriction, portability, and objection are exercised directly on your device as described in Section 8.1. You retain the right to lodge a complaint with a supervisory authority; a list of EEA authorities is available at https://edpb.europa.eu/about-edpb/board/members_en, and the UK authority is the Information Commissioner's Office (ico.org.uk).
8.4 Other Jurisdictions
Privacy laws elsewhere (including China's Personal Information Protection Law (PIPL), Brazil's LGPD, Canada's PIPEDA, and Japan's APPI) grant similar rights of access, correction, and deletion. Because the App keeps all data on your device and we collect none, you likewise exercise these rights directly on your device as described in Section 8.1. Contact us with any questions using the details in Section 12.
9. Minors
The App is not directed at children, and we do not knowingly collect personal data from children under 13 or the equivalent minimum age in your jurisdiction. Because the App collects no data from anyone, no data from children is collected (COPPA, GDPR Art. 8). A parent or guardian can remove all App data by uninstalling the App from the device.
10. International Transfers
The App transfers no User data internationally, because no User data leaves your device. If you contact us by email, your message is received on our email provider's infrastructure, which may be located in another country (including the United States).
11. Amendments
We may amend this Policy from time to time, for example if a future version of the App adds features that change how data is handled. Amendments will be communicated by:
- Publishing the revised Policy at this URL;
- Updating the "Last Updated" date at the top of this Policy; and
- Where reasonably practicable, providing notice within the App when material changes are made.
Your continued use of the App after the effective date of any amendment constitutes acceptance of the amended Policy.
12. Contact and Data Controller
For questions, requests, or complaints regarding this Policy, contact the data controller:
Chunhou Li
Email: diveintothefog@gmail.com