Skyglass  Privacy Policy

Last updated: 13 September 2026

Skyglass is an app for reading and recording the colour of the sky, inspired by Horace-Bénédict de Saussure's cyanometer of 1789. This policy explains what information the app collects, why, who it's shared with, and the choices and rights you have. We've tried to write it in plain English.

Who we are. Skyglass is made by Ben Strak / Studio Strak ("we", "us"). If you have any questions about this policy or your data, contact us at benjaminstrak@gmail.com.

The short version

• There are no accounts. You never give us your name or email.
• Your captures stay on your phone. The photo, the colour and the location of each capture are stored on your device and are not uploaded anywhere in the current version of the app.
• We collect anonymous usage analytics — which features are used, not what you photographed or where.
• By making a capture you give us permission to use it in future — for a shared map, research, exhibitions and promotion of Skyglass — always without your exact location or identity. Details below.
• We never sell your personal data or use it for advertising.

What we collect and why

1. Captures (photo + colour + location + time)

When you press the shutter, the app stores on your device:

• the photo of the sky as seen through the viewfinder,
• the colour it reads from that photo, the wheel it fell on, and the name it assigns,
• the GPS location and the nearest place name, if you have allowed location,
• the date and time.

Why: this is the point of the app — a personal record of the skies you have looked at, shown on your timeline and your map.

In this version, captures are kept only on your device. They are not sent to us or to anyone else unless you choose to share one (see 6 below).

2. Camera access

Used to read the colour of the sky live in the viewfinder and to take capture photos when you press the shutter. The camera feed is analysed on the device to decide whether it is looking at sky; nothing is kept or transmitted until you capture. The app doesn't access your photo library.

3. Motion sensors

The app reads the phone's motion sensors to tell which way it is being held — to judge whether it is pointing at the sky and to move the light on the glass as you tilt. This is processed live on the device and is never stored or sent anywhere.

4. Location access

Used to pin each capture to the place it was taken and to show your captures on the map. We request location "while using the app" only, and you can use Skyglass without it — captures without a location simply don't appear on the map.

5. Anonymous analytics

We use Mixpanel to understand how the app is used: events such as "app opened", "picture captured" (with whether it had a location), "picture shared" (with the colour name), and whether camera and location permissions were granted. Mixpanel assigns each install an anonymous device identifier. We do not send your photos, your colours' raw values, your coordinates, or any contact details.

Why: to see which parts of Skyglass people actually use, so we can improve it.

6. Sharing a capture

If you use the share button, the app builds an image of that capture (the photo, the colour name and a Skyglass watermark) and hands it to the iOS share sheet. Where it goes from there — Messages, Instagram, a saved photo — is your choice and is governed by that service's terms.

7. Feedback (optional)

If you use "Send feedback" in Settings, the message you write, together with the app version and iOS version, is sent to our team's Slack channel so we can read and act on it. No identity is attached unless you include it in your message.

We don't collect advertising identifiers, contacts, or browsing history.

Your captures, and how we may use them in future

Skyglass is designed to grow into a shared record of the sky: a map and archive built from everyone's captures. To make that possible without asking you again later, we ask for your permission now.

By making a capture in Skyglass, you grant Ben Strak / Studio Strak a worldwide, perpetual, royalty-free licence to store, copy, adapt, display and publish that capture — meaning the sky photo, the colour and its name, the date and time, and an approximate location — for the following purposes:

• showing captures on a shared map and archive inside Skyglass, alongside other people's, in future versions of the app;
• scientific, artistic and educational research into the colour of the sky, including sharing or licensing anonymised capture data with researchers, universities, charities and cultural institutions, including on commercial terms;
• exhibitions, publications, prints, films and other artworks derived from the collective record;
• promoting Skyglass and Studio Strak, for example in App Store screenshots, on our website and on social media.

What this never includes: your exact GPS coordinates (any location we use or publish is rounded to roughly a kilometre), your name, your contact details, or anything that identifies you. Captures are not linked to an identity because Skyglass has no accounts.

What you keep: you remain the owner of your photos. This is a licence, not a transfer. You can carry on using your captures however you like.

Deleting a capture (the trash icon on a capture) removes it from your device. Once captures are being uploaded in a future version, deleting one in the app will also remove it from the shared record, and we won't use it in new work after that. Work already published — an exhibition print, a research dataset already handed over — can't be recalled.

Nothing is uploaded yet. In the current version every capture stays on your phone. Before any version of Skyglass begins uploading captures we will update this policy, change the "Last updated" date, and say so clearly in the app.

Because captures may one day be public, please photograph the sky — not people, faces, vehicle number plates, or anything you wouldn't want to be seen.

Who else handles your data (processors)

• Mixpanel — receives the anonymous usage events described above. Governed by Mixpanel's privacy policy.
• Apple — provides MapKit for the map, the on-device Vision framework that recognises sky, and TestFlight during betas. Governed by Apple's privacy policy. Map tiles are requested from Apple as you pan and zoom, which tells Apple roughly which area you are looking at.
• Slack — receives in-app feedback messages you choose to send.

We do not sell your personal data to anyone.

Legal basis (UK/EU GDPR)

Where UK/EU data protection law applies, we rely on:

• Consent — for camera and location access (you grant these through iOS, and can withdraw them anytime in Settings), and for the licence over your captures described above, which you give by choosing to capture.
• Legitimate interests — to operate and improve the app, keep it secure, and respond to feedback.

Keeping your data / your rights

• Deletion: delete any capture in the app with the trash icon. Deleting the app removes every capture from your device. To ask us to remove anything we hold about you — for example feedback you sent — contact us at benjaminstrak@gmail.com.
• Retention: captures live on your device until you delete them. Analytics events are retained by Mixpanel according to our account settings; feedback messages are kept as long as they are useful to us.
• Your rights: under UK/EU law you can request access to, correction of, or erasure of your personal data, and object to or restrict certain processing. Contact us to exercise these.
• Complaints: if you're in the UK, you can complain to the Information Commissioner's Office (ICO) at ico.org.uk.

Security

Captures are stored in the app's private storage on your device, protected by your device passcode and iOS's encryption. Anything the app does send — analytics events and feedback — travels over encrypted HTTPS connections.

Children

Skyglass is not directed at children under 13. We don't knowingly collect data from children. If you believe a child has provided us data, contact us and we'll remove it.

Changes to this policy

We may update this policy as the app evolves — in particular when captures begin to be uploaded to a shared map. We'll change the "Last updated" date above, and for significant changes we'll make a reasonable effort to notify users in the app.

Contact

Ben Strak / Studio Strak
benjaminstrak@gmail.com