App Overview

Reciprocity Timer icon

Reciprocity Timer

Pump Interactive · Photo & Video

Manage your film photography from start to finish! 

$1.99 · In-app purchases

PRICE
$1.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
2.5
4 ratings · Below Average

Evidence scope: No current overall US chart position is available. Category-chart positions shown in discovery are a separate scope. Revenue is a directional model estimate, not verified earnings.

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A product spec, screen plans, and build steps for your coding agent.

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What's included17 files

A product spec, phased build plan, differentiation notes, and screen references.

  • START_HERE
  • AGENTS
  • EVIDENCE
  • SPEC
  • BUILD_PLAN
  • DIFFERENTIATION
  • skills/
  • screens/
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Illustrative example: an invoice app for independent contractors. Your kit is tailored to the app you choose; this is not its generated content.

Feature spec

Goal: Send a clear invoice after finishing a job.

  • Add a client, line items, a due date, and payment instructions.
  • Preview the total before exporting a PDF.
  • Keep an editable draft if export fails.

Screen plan

Invoice editor: Client at the top, editable line items in the middle, total and preview action at the bottom.

States: Empty draft, validation errors beside each field, exporting, and a retry action that preserves the draft.

Differentiate and validate

Hypothesis: Contractors need faster repeat invoices more than more templates.

First experiment: Test duplicating a previous job with five contractors. Watch where they hesitate before expanding the feature set.

The full kit adds a phased build plan, evidence notes, tool prompts, and implementation guidance. It is a plan for your coding agent, not a finished app.

Usage: Mechanics are fair game; never reuse the original name, branding, assets, or verbatim copy.

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Quick prompt

> SELECT BUILD PLATFORM:

Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.

// RORK SYSTEM PROMPT
Rork plan preview for Reciprocity Timer: map the core Photo & Video workflow, choose the smallest differentiated feature set, define the data and monetization boundaries, then prototype the riskiest user journey first.
            

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Opportunities

AI-GENERATED OPPORTUNITY HYPOTHESES

These are generated suggestions, not verified review quotations. Check current App Store reviews and speak with users before treating a possible gap as a requirement.

Hypothesis 1

Offer advanced editing tools and filters.

Assumption to check: Limited functionality compared to full-featured photo editors.

Validate with people who use this workflow before building.

Hypothesis 2

Implement a guided onboarding experience.

Assumption to check: User interface can be confusing for new users.

Validate with people who use this workflow before building.

Hypothesis 3

Optimize image handling for better performance.

Assumption to check: Performance issues with high-resolution images.

Validate with people who use this workflow before building.

Hypothesis 4

Integrate social media sharing options.

Assumption to check: Lack of social sharing features.

Validate with people who use this workflow before building.

App evidence

Original App Store material. Ratings and screenshots describe the existing app, not proof of demand for your version.

App Store description

Manage your film photography from start to finish!  Reciprocity Timer has 2 Version - the "Standard" Version does NOT include advanced features but can be used to calculate reciprocity on a range of common films. The "Pro" Version is available for an additional $9.99 USD (via in-app-purchase) unlocks a range of advanced features. The initial purchase price allows you to calculate reciprocity for all the films included by selecting an observed exposure time. This $1.99 US non-pro version is suitable for people who just need to calculate an exposure that includes reciprocity adjustments for commonly used films. It will suit many users who don't require or need to upgrade to the pro version for features like note keeping or a camera database etc. It's most suitable if you are new to film. More advanced film users and photographers may want to pay to upgrade after their initial purchase to the pro version. If you use a pro-feature you'll be prompted to upgrade for an additional $9.99 US. This will unlock all the additional features including the Zone Editor, Note, Camera and Film Holder database as well as custom films and filters. There is no need to upgrade if you just want to calculate and time reciprocity for a particular film and you always use the same camera. The app includes in-app purchase to unlock pro features including a note-keeping feature, the ability to add custom films and the ability to select often used film stock as favorites. Once you upgrade then the one app does it all - notes, filters, exposure calculations, custom films, zone system editor, film holder management as well as the reciprocity math! A comprehensive film reciprocity calculator for photographers. Select a film type and metered exposure time - the calculator will provide a reciprocity compensated exposure time. The app includes an exposure timer so you can time your long exposures. You can also use a slider to adjust exposure when you have filters attached. The app supports a wide range of film stocks and allows the user to add various common exposure filters such as NDs and Polarizers. Keep detailed notes and share them. Share your adjusted exposure times with colleagues. This app makes film photography a breeze. You may need to setup Reciprocity Timer in Settings -> Notification Center to ensure the app's timer can notify you when exposures are ending and your device is asleep. Watch companion app now included. To install the app use the Apple Watch App on your phone. Ensure your watch and phone are paired an unlocked and scroll down the list of available apps to Reciprocity Timer. Select Install. You can also turn on "Automatically Install Apps".

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Screenshots

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Build scope

Plan a focused first version with your coding agent. These are planning assumptions, not a delivery guarantee.

Define the first version

Choose one audience and one core workflow. Use the kit to agree on its screens, data, and acceptance criteria before building.

Set boundaries

Decide which secondary features, integrations, and platform support can wait. Your version does not need to reproduce everything in the original.

Check the hard parts

Validate external services, specialist technology, data access, and ongoing costs for your chosen scope.

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BUILD KIT DIFFICULTY
Starter

From the Build Kit assessment.

A reliable timeline needs an agreed scope and a technical check. Ask your agent to estimate the phases in BUILD_PLAN.md after that review.