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T
Thibaud R
Known Participant
October 23, 2025
해결됨

Lightroom Classic 14.5 (Windows) — SDK ignores TIFF color profile (always sRGB) and can’t access Exp

  • October 23, 2025
  • 1 답변
  • 117 조회

Title: Lightroom Classic 14.5 (Windows) — SDK ignores TIFF color profile (always sRGB) and can’t access Export Presets from Lua

Environment

  • Windows 10/11

  • Lightroom Classic 14.5.1 (English UI; previously tried French too)

  • Lightroom SDK (Lua) as shipped with Lr 14.x

Goal
Programmatically export TIFF 16-bit with ProPhoto RGB profile via plugin (no UI interaction). If the profile can’t be injected through exportSettings, we’d like to export via a user Export Preset object (TIFF + ProPhoto) from Lua.

What works

  • Exporting manually through the Export dialog using a user preset (TIFF 16-bit + ProPhoto RGB) produces correct ProPhoto-tagged TIFFs.

  • Our plugin can export TIFF 16-bit and control destination, naming, compression, etc.

What fails

  1. When we pass color-profile keys inside exportSettings to LrExportSession, the resulting TIFFs are still sRGB:

    • LR_format="TIFF" → respected

    • LR_tiff_bitDepth=16 → respected

    • LR_tiff_compressionMethod="compressionMethod_None" → respected

    • But LR_outputProfile="C:\\Windows\\System32\\spool\\drivers\\color\\ProPhoto.icm" and/or LR_outputProfileName="ProPhoto RGB" → ignored (files come out as sRGB)

  2. We cannot obtain an Export Preset object from Lua on this build:

    • pcall(function() return catalog:getExportPresets() end) → error (type=string)

    • pcall(function() return LrApplication.exportPresets() end) → error (type=string)
      → Therefore we can’t do exportPreset = <presetObject> as a workaround.

Minimal reproducible test (plugin below)

  • The test writes 3 TIFFs for the selected photo, trying three profile variants:

    • A_nameOnly: only LR_outputProfileName = "ProPhoto RGB"

    • B_pathOnly: only LR_outputProfile = "C:\\Windows\\System32\\spool\\drivers\\color\\ProPhoto.icm"

    • C_both: both keys together

  • All other keys are minimal and valid.

  • Result on our system: all 3 outputs are TIFF 16-bit but tagged sRGB.

Questions

  1. Is this a known regression/limitation on LrC 14.5.x where LR_outputProfile / LR_outputProfileName inside exportSettings are ignored for TIFF?

  2. Is there a documented alternative key (or combination) that reliably forces ProPhoto RGB for TIFF from Lua?

  3. Under what conditions should catalog:getExportPresets() / LrApplication.exportPresets() work in 14.5.x? Is there any configuration/state that disables these APIs?

  4. What is Adobe’s supported method to trigger a TIFF+ProPhoto export from a plugin if exportSettings ignores color profile and preset APIs are unavailable?

Thanks in advance. We can provide logs and the exact TIFFs if helpful.

    최고의 답변: johnrellis

    "We cannot obtain an Export Preset object"

     

    The SDK doesn't provide this ability. However, a plugin can read the Export presets (which are simple Lua-syntax files) from the preferences folder Lightroom/Export Presets.

     

    To see the specific settings you need to pass to LrExportSession():

     

    1. In the Export window, create a preset with the desired settings.

     

    2. In the Export window's Preset panel, right-click the preset and do Show In Finder / Show In Explorer. That will open Finder/Explorer with the preset's .lrtemplate file selected.

     

    3. Edit the preset's .lrtemplate file in a text editor to see all the key/values. Note that for some gratuitous reason, you need to prefix the keys with "LR_" when passing them to LrExportSession, e.g.

    LR_export_colorSpace = "ProPhotoRGB",

     

    1 답변

    johnrellis
    johnrellis답변
    Legend
    October 23, 2025

    "We cannot obtain an Export Preset object"

     

    The SDK doesn't provide this ability. However, a plugin can read the Export presets (which are simple Lua-syntax files) from the preferences folder Lightroom/Export Presets.

     

    To see the specific settings you need to pass to LrExportSession():

     

    1. In the Export window, create a preset with the desired settings.

     

    2. In the Export window's Preset panel, right-click the preset and do Show In Finder / Show In Explorer. That will open Finder/Explorer with the preset's .lrtemplate file selected.

     

    3. Edit the preset's .lrtemplate file in a text editor to see all the key/values. Note that for some gratuitous reason, you need to prefix the keys with "LR_" when passing them to LrExportSession, e.g.

    LR_export_colorSpace = "ProPhotoRGB",

     

    T
    Thibaud R작성자
    Known Participant
    October 25, 2025

    Hi John,

    That’s absolutely spot on — thank you so much for taking the time to explain it so clearly.

    Your answer about checking the .lrtemplate file and using LR_export_colorSpace = "ProPhotoRGB" inside exportSettings solved the issue right away.

    We’d been going in circles for hours trying every possible combination of keys, and your explanation about the “LR_” prefix finally unlocked it. It’s such a simple detail but it makes all the difference.

    Really appreciate your help — this was a huge time saver!

    Best,
    Thibaud

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