Calibrating a process takes about fifteen minutes — not long in absolute terms, but repeated monthly across three different processes, it quickly adds up to several hours a year. If your parameters don't change (same paper, same chemistry, same UV source), there's no reason to redo the measurement on every print. The presets library exists to reuse a previous calibration without going back through the whole pipeline.

A preset, in Calibration Flow, is a snapshot of your calibration at a given moment — the curve you generated, the export options you chose, the name you gave it. You find it again in the library the next time, you click to apply it, and you start from that base. It's the mechanism that turns Calibration Flow from a measurement tool into a tool of recurring production.

#What you do

When you've finished a calibration and you want to keep it, you click "Save preset". The app asks you for a name. It's the only field you fill in manually — typically something like

cyanotype-arches-mai-2026

. The other information (the curve, the export parameters you chose in the Negative module, the date) is captured automatically from your current state.

The preset is saved locally on the device you're using. You find it in the library as a list — a name, a date, a button to recall it. You click to recall: the curve is immediately loaded as the active curve, the export options return to what they were at the moment of saving. You can now generate a negative with exactly this calibration, export the

.acv

that depends on it, or adjust slightly if something has changed.

You can rename a preset, delete a preset (irreversible action — be careful), and duplicate a preset (useful for starting from an existing calibration and modifying it without touching the original).

#Why it matters

For recurring production. If you regularly print cyanotype on the same paper with the same chemistry, you don't need to re-calibrate each month. You take your existing preset, you check on a quick test target that nothing has drifted, and you produce. The full measurement calibration you do once per chemistry batch, not once per print.

For comparison between parameters. You can have three presets side by side:

cyanotype-arches

cyanotype-hahnemuhle

cyanotype-fabriano

. When you prepare a new print, you choose the preset that matches your paper. No confusion, no calibrating the wrong variant by mistake.

For tracking chemistry drift. Keep all your presets dated. After a year, you can compare the May 2026 curve to the May 2027 one. If they diverge, your chemistry has changed. It's a simple and precise measure of the quality of your batches over time.

#When you don't need it

For a one-off calibration without repetition. If you do a single measurement for a one-off project with no intent of reuse, export the

.acv

directly and move on. The library is for long-term memory, not one-off gestures.

If you work entirely in Photoshop after the export. Once your

.acv

is loaded in Photoshop, you can reuse it from Photoshop directly (by saving it as a Photoshop curve preset). Calibration Flow doesn't need to be reopened to reapply the curve to new images.

For quick tests with no intent of keeping them. If you test a new chemistry dilution on a target, you can generate the curve to see, without saving as a preset. The library only fills up if you save explicitly.

#Worth remembering

Element	Value
Contents of a preset	Curve + export options + name + date
User input	Only the name is asked manually
Storage	Local on the device (browser IndexedDB or iOS)
Cross-device synchronization	Active with an account + Pro subscription
Editing a preset	Rename, duplicate, delete
Reapply	One click from the library
Deletion	Irreversible (no trash)

#The test

Generate a calibration on a test image. Save it with a descriptive name. Quit the app completely and reopen it. Go to the library — your preset should be there with the right name and the right date. Click to recall it: the curve should come back as is, identical to what it was at the moment of saving. If the recalled curve differs from the saved one, either the preset didn't capture the complete state, or the app changed something between saving and recall — report it.