Workflow · Lightroom
Lightroom does not read .acv. Three workarounds, pick yours.
Calibration Flow exports to Adobe’s .acv format. Lightroom — made by the same company — does not read it. Three workarounds exist, matched to your current setup. None is as clean as the direct Photoshop workflow; all of them work.
Article reviewed by Tristan Sidem (Calibration Flow founder) + Raphaël Lebas de Lacour (Vision Picturale co-founder).
An old Adobe asymmetry
The .acv was designed for Photoshop in 1991. Lightroom, released sixteen years later, has its own Tone Curve module based on a different internal representation — capped at 14 points versus 16 in the .acv format. The two Adobe applications do not share the format. It is old, it does not move.
For alt-process photographers subscribed to Lightroom alone (without Photoshop), this is a concrete difficulty. The three workarounds below cover the usual cases: full Creative Cloud Photo, Lightroom alone, or a quick one-off need.
Three ways, one format
Calibration Flow → .acv → Lightroom, without native support
Choose by your setup and tolerance for effort. All three lead to a calibrated print; they differ on the precision preserved and the setup time.
Workaround 1 · Cleanest
Photoshop preset + droplet, triggered from Lightroom Classic
You save your .acv as a preset in Photoshop (Curves panel → Save Preset). You create a Photoshop action that applies the preset, convert it to a droplet (File → Automate → Create Droplet), place the droplet in Adobe/Presets/CalibrationFlow/. In Lightroom Classic, you point at the droplet via Edit → Preferences → External Editing. You get a right-click → Edit In → your process.
Precision: maximal, full 16 points. Effort: 30 minutes of initial setup, then one click. Requires: a Creative Cloud Photo subscription (Photoshop + Lightroom Classic).
Workaround 2 · Lightroom alone
Manual entry in the Tone Curve module
You read the coordinates of your curve points in Calibration Flow (the 25 sampling points give you reference marks, and the 9 to 14 retained points are shown on the graph). You open Lightroom’s Tone Curve module and place the 14 most representative points one by one. Count five to ten minutes the first time, two minutes after.
Precision: reduced, about 1% deviation in L* (visible only on very smooth ramps). Effort: repeated per curve. Requires: Lightroom alone is enough, works on Lightroom Cloud too.
Workaround 3 · Fastest
Intermediate TIFF
You export your image from Lightroom as a high-quality TIFF into a temporary folder. You open it in Calibration Flow, which can apply its own curve to any imported image. You export the corrected TIFF and re-import it into Lightroom as a new file.
Precision: maximal. Effort: 5 minutes per image. Limit: you break Lightroom’s non-destructive workflow — the corrected TIFF loses the link to its original RAW. For a one-off print, it is fast. For a run, it gets tedious.
Which to choose for your setup
| Situation | Workaround | Precision |
|---|---|---|
| You have full Creative Cloud Photo | 1 · Photoshop droplet | Maximal |
| You have Lightroom alone (Classic or Cloud) | 2 · Manual entry, 14 points | Reduced (~1% in L*) |
| You want a quick one-off print | 3 · Intermediate TIFF | Maximal (workflow broken) |
| You work fully on mobile | 2 · Manual entry in Lightroom mobile | Reduced |
Before Calibration Flow / after
Before
You push points in the Tone Curve by eye, with no reference. No written trace. To repeat the same result on the next photo, you copy-paste the Lightroom develop preset, which works as long as the file stays — but no way to recreate the curve elsewhere in six months.
After
Calibration Flow generates an .acv that becomes your source of truth. You pick your workaround and reach the target result in Lightroom. Six months later, you replay the same curve — the .acv file is still there.
Access
The web version of Calibration Flow is free with sign-up, no credit card. You generate your .acv and pick the workaround that matches your Adobe subscription.
Web
Free with account
No credit card. Full workflow, unlimited .acv export.
iOS
€9.90/month
Optimised iPhone capture. Cloud sync included.
Luminograph
1 year of Pro included
Shipped with a Luminograph purchase from Vision Picturale. Custom test charts + Color Venn.
Lightroom questions
Five practitioner questions
- It is a long-standing asymmetry Adobe has never resolved. The .acv was created for the Photoshop Curves panel in 1991. Lightroom, released in 2007, was built with its own Tone Curve module based on a different internal representation (limited to 14 points versus 16 for the .acv). Adobe’s product teams kept the two silos separate, probably to avoid re-architecting Lightroom. No public roadmap in 2026 mentions native .acv support on the Lightroom side. It is frustrating, but that is the situation.
- Count thirty minutes the first time: save the .acv as a preset in Photoshop, create a Photoshop action that applies the preset, convert the action to a droplet, and point Lightroom Classic at the droplet via Preferences → External Editing. Once configured, triggering it from Lightroom becomes a right-click → Edit In → Calibration Flow Cyanotype (or whatever you named the droplet). This is the cleanest workaround if you already have a full Creative Cloud Photo subscription.
- Yes for most processes. Lightroom caps at 14 points versus 16 in the .acv. You select the 14 most representative points of your Calibration Flow curve and enter them one by one. The final deviation on the result is about 1% in L*, visible only on very smooth ramps. For cyanotype, gum bichromate, Van Dyke, it is below the variation threshold you will face anyway from chemistry and paper. For platinum/palladium, where every inflection matters across the wide range, prefer workaround 1.
- Yes, and that should be understood before choosing this route. You export your developed RAW as a high-quality TIFF, process that TIFF in Calibration Flow (which applies its own curve), then re-import the corrected TIFF. The new file loses the link to its original RAW — if you want to re-develop later, you start again from the RAW in Lightroom and redo the TIFF round trip. It is the fastest method to set up (five minutes), but the least clean long term. Favour it for a one-off test or a single print, not for a production run.
- Partially. Lightroom mobile has neither a Photoshop droplet nor an easy TIFF bridge. You only have manual entry in the Tone Curve module (also limited to 14 points on the mobile version). If you work fully on mobile, the alternative that works is to use Calibration Flow iOS to generate your curve, open your image in Calibration Flow or Affinity Photo iPad, apply the correction, and re-import the result into Lightroom mobile via Photos or iCloud Files. It is heavy for regular use.
Three workarounds. One curve.
Calibration Flow Web is free with sign-up. Generate your curve, pick the workaround that fits your Adobe setup, run your calibrated print.
Try it free — no credit card