Privacy Policy for Fractune

Last updated: May 2026

1. Who We Are

This privacy policy describes how Fractune (developed by Colours by Barslund, Denmark) processes your personal data when you use our app or website, contribute facade readings to the public dataset, or contact us for support.

Fractune (Colours by Barslund)
c/o Anders Barslund
Abildgaardsvej 51
2830 Virum, Denmark
Tel: (+45) 60 63 40 24
Email: legal@fractune.dk

2. What Data Do We Collect?

When you use Fractune, we collect and process the following types of data:

• Image analysis (on-device only): Photographs of facades you analyse are processed entirely on your iPhone and never leave the device unless you explicitly choose to contribute the analysis to the public dataset.
• Anonymous reading metrics (opt-in): If you accept research data sharing, we collect the computed values from each analysis: Architectural Fluency F, fractal dimension D, the four dimension sub-scores, lacunarity, edge-orientation entropy, spectral slope, balance, hierarchical scaling, solid/void ratio, curvature ratio, value contrast, the chromatic palette and harmony type, plus a contributor ID (a randomly generated UUID stored on your device). No data can be linked to your personal identity.
• Optional location and orientation: Latitude, longitude, camera heading, and pitch, only when you explicitly enable location sharing for a reading. You can toggle this per reading and revoke it in app settings at any time.
• Optional building metadata: If you enrich a reading with a building's name, address, architect, style, or construction year, this metadata is published with the reading.
• Optional redacted training images: If you separately consent to image donation, a face-redacted JPEG of the facade is included with the reading. Faces are detected and blurred on your device before upload.
• Queries and support: If you contact us, we process your name, contact details, and query to provide assistance.

3. Legal Basis and Storage Periods

• Anonymous reading metrics: our legitimate interest (GDPR art. 6(1)(f)) in researching architectural fluency, validating the F formula, and improving the analysis pipeline. Data is published as part of an open dataset and cannot be used to identify individuals.
• Location, orientation, building metadata, and redacted images: your explicit consent (GDPR art. 6(1)(a)). You can withdraw consent at any time in app settings, after which future readings will not include these fields.
• Erasure requests: you may request deletion of all readings linked to your contributor ID at any time. We process erasure requests within 30 days and log the action for accountability (GDPR art. 30).
• Queries/support: stored for up to 3 months after last contact unless required for dispute or legal documentation.

4. Purpose of Processing

We use your data to:

• Analyse facades on-device and present results to you
• Build and maintain the public Fractune dataset at sites.fractune.dk
• Calibrate and validate the Architectural Fluency F formula against real-world readings
• Support scientific research into fractal geometry, perceptual aesthetics, and architectural composition
• Comply with legal obligations (accounting, documentation)
• Defend our rights in case of disputes or regulatory investigations

Aggregated, anonymised dataset readings may be shared with or sold to third parties, such as architecture firms, research institutions, or urban planning bodies, for research and product development. No data is ever shared that can identify you as an individual.

5. Storage, Security & International Transfers

• Anonymous dataset readings are stored in Apple's CloudKit (public database) under our developer container.
• Your local session history (the readings shown on your device's history view) is stored locally on your iPhone and is not synced to any cloud service.
• Support inquiries are stored securely with access limited to authorised personnel.
• Data is not transferred outside the EU/EEA except as required for secure processing by Apple, who complies with GDPR requirements as a data processor.

6. Cookies and Tracking

Fractune does not use cookies or tracking technologies to collect data about your use of the app or website. We do not use analytics for advertising or profiling purposes. The website serves a short-lived Apple MapKit JS token to render the public sites map; this token does not identify you.

7. Disclosure to Third Parties

• Service providers and IT suppliers who help us deliver our services (Apple for CloudKit and MapKit; hosting providers for the Astro/Vercel website).
• External advisors (e.g. accountants, legal counsel).
• Other third parties with your consent, or in the case of mergers or legal requirements.
• Anonymised reading metrics, including F, D, and dimension sub-scores, are publicly available via sites.fractune.dk.

8. App Attest and Device Authentication

To prevent abuse of our public dataset, the app uses Apple's App Attest framework to prove that submissions come from a legitimate Fractune install on a real Apple device. App Attest does not transmit your Apple ID, device serial number, or any personally identifiable data, only a cryptographic attestation that the submission originates from an authentic copy of the app. See Apple's documentation for details.

9. Your Rights

You have the right to:

• Request access to or a copy of your data (provide your contributor ID, found in app settings)
• Request correction, erasure, or restriction of your data
• Object to our processing or to data used for research
• Withdraw your consent at any time (for location, image donation, building metadata)
• Complain to the Danish Data Protection Agency at www.datatilsynet.dk

To exercise your rights, contact us at legal@fractune.dk or by mail/phone (see above).

10. Children

Fractune is not directed at children under the age of 13. We do not knowingly collect personal data from children. If you believe a child has contributed data through Fractune, please contact us so we can promptly delete the affected readings.

11. Changes to this Privacy Policy

We may update this privacy policy as our services evolve or as required by law. Significant changes will be communicated via the app or website, and the consent flow will request renewed agreement when the scope of data collection materially changes. Your continued use after changes means you accept the updated policy.

Fractune – developed by Colours by Barslund