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Finding the Cheapest Lab
Use this when: you've got one specific roll — a stock, a price, a shooting speed — and you want to know what it'll actually cost once it's developed, and which of your saved labs to send it to.
This is the Film Lookup tab.
- Set Format (top of the app, above the tabs) to match the film you're costing out — 35mm, 120, etc. It applies across the whole app, not just this tab.
- In the Film block, fill in:
- Box Speed — the rated ISO on the box.
- Process — C41, B&W, E6, or ECN-2.
- Film Cost and Postage — split out so you can see each separately; the app adds them together for every calculation below.
- Rolls and Exposures per Roll — if you bought a multi-pack, put the pack's total cost against the pack's roll count; the app works out cost per roll and per photo either way.
- If you're not pushing or pulling, leave Shooting at (Target ISO) alone — tap "= box speed" to snap it to match, or just leave it blank once you've entered Box Speed. Only change it if you're deliberately over- or under-exposing (Box 400, shooting at 800 = pushing 1 stop).
- Scroll down to Labs For This Roll — every saved lab is compared automatically, already sorted cheapest-first.
Right under Target Speed, a card shows your total cost per photo (film + dev) — orange if a cheaper film already in your Library would beat it at this same box speed, green if this is already the cheapest option. If you've set a home lab in Settings, this figure uses your lab's price, with the actual cheapest lab noted underneath if a different one would be cheaper.
Further down, Labs For This Roll shows up to four highlighted picks:
| Card | What it means |
|---|---|
| 🏆 Cheapest Total | The absolute lowest cost per photo, any lab, any service tier. |
| ⚡ Cheapest Fastest | Cheapest among labs offering next-day turnaround. |
| 🔍 Cheapest Hi-Res | Cheapest among labs offering hi-res scans. |
| ⚡🔍 Cheapest Hi-Res + Fastest | Cheapest among labs offering both — highlighted gold instead of green if it's within your configured threshold of the absolute cheapest, since a small premium for both perks is usually worth it. |
If two of these land on the same lab/tier, they're shown once with combined labels instead of repeating the card.
Below that, All Options lists every remaining lab/tier — tap ⚡ Next Day or HI-RES to filter the list, tap a row to expand its full film + dev + push/pull breakdown, and tap 📌 on any result to pin it: change the film details afterwards and the pinned card stays on screen, showing how the new numbers compare against it. Pins persist across reloads until you unpin them.
Tap 🔗 Share Link (next to Save to Library) to copy a URL that reopens this exact roll — same Box Speed, Process, Film Cost, Postage, Rolls, Exposures, Target ISO, and Format, pre-filled and already calculated. Useful for bookmarking a roll you cost out often, or sending someone else the exact numbers instead of describing them.
This is entirely a browser-side shortcut, not a server API — opening the link runs the same
calculation your browser would do if you'd typed the numbers in yourself. A tool that can open a URL
in a real browser (or a person) can use it; a plain curl/script request can't, since there's no
server computing anything — the link just carries the inputs, and results appear once the page's own
code runs.
The URL looks like:
https://filmcalc.trentbauer.com/?format=35mm&process=C41&boxSpeed=400&filmCost=18&postageCost=3.95&rolls=1&exposures=36&devSpeed=800
Every parameter is optional and matches a Film Lookup field — leave any out and that field is left as
whatever's already there. onceOffFee/perRollFee are also supported and auto-expand "More options"
if present.
- A lab that's cheapest at box speed isn't always cheapest once you push. Push/pull fees (flat or per-stop) can flip the ranking — that's the whole reason this comparison runs live against your actual Target Speed, not just Box Speed.
- The orange/green cost card only compares films at the same Box Speed, Process, and Format. It won't suggest a 400-speed alternative for a 200-speed roll — for cross-ISO comparisons (e.g. "what's cheapest if I shoot at 800, pushed or pulled from anything I own?"), use the Per ISO view on the Dev Cost tab instead.
- A film's own push/pull limit matters. Set Max Push/Pull per film stock in the Library (defaults to 1 stop) — a warning appears here if the roll you're costing out exceeds that film's own tolerance, whether it was pushed manually or loaded from a saved profile.
- 💾 Save to Library carries whatever you've typed (Box Speed, Total Cost, Rolls, Exposures) over to a new film profile — handy right after you've costed out a roll you actually bought, so it's available next time without re-typing.