Help / Support — Exposure Calculator

Welcome!

This page shows how to use the app, calibrate, and connect to Google Sheets so your exposures are saved and sorted newest-first.

If you get stuck, scroll to Troubleshooting or Contact.

Quick start

  1. Enter three numbers

    - Baseline Exposure start a bit high, this is where overexposing it better.

    - First Max Black Step — first wedge step that reaches full black and where you can not see a line from the transparency (white for gravure).

    - Steps per Stop — 2 for 21-step wedges or 3 for 31-step.

    2. Pick your process, and optionally add Paper, Ink, Aquatint timing.

    3. Tap Calibrate → the app shows your Standard Exposure.

    4. (Optional) Export to Google Sheets so you can keep a running log.

    5. help Videos

    - Intro into the app
    - Setup Google Sheet + Web App
    - Step wedge & calibrateeb App

How to calibrate (short version)

  1. Print a step wedge using a generous baseline exposure.

  2. Dry and inspect. Find the first step that reaches max black (or brightest white) where you can not see a line from the transparency.

  3. Enter that step number in First Max Black Step.

  4. Enter your wedge type in Steps per Stop (2 or 3).

  5. Tap Calibrate to get your Standard Exposure.

  6. If steps 1 & 2 aren’t both solid, increase the baseline and reprint until they are, this is where a long exposure is always better than a short exposure..

Save to Google Sheets (one-time setup)

You’ll do this once per sheet. After that, just export.

1. Create the sheet

- New Google Sheet → in row 2 (A–F) paste:

`DATE | PROCESS | STANDARD EXPOSURE TIME | PAPER TYPE | INK TYPE | AQUATINT TIMING`

- Tip: in the app’s Help tab tap Copy header line.

2. Add the Apps Script & deploy as a Web App

- Extensions → Apps Script** in your sheet.

- Paste the script from the app’s Help tab (Copy Apps Script).

- **Deploy → New deployment → Web App

- Access: Anyone with the link

- Copy the URL that ends with /exec

3. Paste the Web App URL into the app

- In the app: Help → Open Settings → paste the /exec URL → Save.

- Tap Test Export** to confirm a new row appears.

Everyday exporting

Calibrate → Standard Exposure → Export to Google Sheets.
Your row is tinted by process, with today’s date and two-decimal exposure.

Troubleshooting

Non-JSON / “doGet not found”
Paste the script again, Deploy → New deployment → Web App, and use that /exec link.

“Not a Web App URL”
Must end with /exec (not the editor link). The app can normalize some googleusercontent.com/macros/echo links, but /exec is best.

Colours missing
Run Save in Settings (triggers formatting), or call the web app with ?action=format.

Dates not sorting
Use the in-app script so dates are coerced and then sorted Date-desc + timestamp.

New sheet
Repeat setup and update the URL in Settings → Test Export.

Subscription & billing

  • Auto-renewable yearly subscription for full access.

  • Charged to your Apple ID; manage in Settings → [your name] → Subscriptions.

  • Apple handles billing; we never see your card details.

Data safety

  • On-device we store your sheet URL and aquatint timing.

  • Exports go directly to your Apps Script and into your sheet.

  • We don’t collect your entries on our servers.

    Full details: Privacy Policy → https://itsasalfordthing.co.uk/privacy-policy-exposure-calculator

Contact us.