Author Topic: Using PM+ with Negative Lab Pro  (Read 381 times)

Offline timhenrion

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Using PM+ with Negative Lab Pro
« on: February 08, 2026, 08:48:55 AM »
I'm a new PM+ customer who has digital and analog workflows and uses Lightoom Classic & Photoshop as my primary editing tools.

For my analog workflow, I use a Lightoom Classic 3rd-party addon called "Negative Lab Pro" (https://www.negativelabpro.com/). This program applies film-custom profiles and adjustments to properly edit/display scanned film negative DNG's as positives in Lightroom Classic. It's *fantastic* for anyone who works with film negatives in Lightroom Classic. You scan your negatives to DNG using either Hamrick VueScan or Silverfast and then "process" them to positives using Negative Lab Pro in Lightroom Classic.

I'm migrating over to PM+ as my primary DAM from a metadata standpoint, using PM+'s Catalog feature. From a PM+ "Preview" perspective, I'm looking to be able to see properly "processed" thumbnails and previews of my negatives in PM+, using PM+'s "Use Adobe DNG Converter to generate previews feature.

My main issue/question is: How do I get PM+ to generate Thumbnails for these DNGs using Adobe DNG Converter so that I can see proper positive thumbnails? PM+ appears to be pulling previews from the DNG scans of my negatives, causing them to show up in contact sheets as negatives, not positives.

Is there any way to have PM+ use Adobe DNG Converter for Thumbnail generation for these DNGs?

Thanks!

Tim Henrion
Fashion/Fine-Art Photographer
Palm Coast, FL
https://www.timhenrion.com

Offline Kirk Baker

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Re: Using PM+ with Negative Lab Pro
« Reply #1 on: February 09, 2026, 09:55:43 AM »
Tim,

I'm a new PM+ customer who has digital and analog workflows and uses Lightoom Classic & Photoshop as my primary editing tools.

For my analog workflow, I use a Lightoom Classic 3rd-party addon called "Negative Lab Pro" (https://www.negativelabpro.com/). This program applies film-custom profiles and adjustments to properly edit/display scanned film negative DNG's as positives in Lightroom Classic. It's *fantastic* for anyone who works with film negatives in Lightroom Classic. You scan your negatives to DNG using either Hamrick VueScan or Silverfast and then "process" them to positives using Negative Lab Pro in Lightroom Classic.

I'm migrating over to PM+ as my primary DAM from a metadata standpoint, using PM+'s Catalog feature. From a PM+ "Preview" perspective, I'm looking to be able to see properly "processed" thumbnails and previews of my negatives in PM+, using PM+'s "Use Adobe DNG Converter to generate previews feature.

My main issue/question is: How do I get PM+ to generate Thumbnails for these DNGs using Adobe DNG Converter so that I can see proper positive thumbnails? PM+ appears to be pulling previews from the DNG scans of my negatives, causing them to show up in contact sheets as negatives, not positives.

Is there any way to have PM+ use Adobe DNG Converter for Thumbnail generation for these DNGs?

If you can get the previews in the DNG files updated to reflect the effects that your Negative Lab Pro does, then PM will pick those up directly.  If not, and using the DNG converter on your DNG files does update the previews, you can have PM render RAW files (DNG is a RAW file format) with the Adobe DNG Converter.

https://docs.camerabits.com/support/solutions/articles/48000361383-raw-rendering-in-photo-mechanic

HTH,

-Kirk

Offline timhenrion

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Re: Using PM+ with Negative Lab Pro
« Reply #2 on: Yesterday at 10:27:15 AM »
Hi Kirk,
I'm already able to successfully render previews in PM+ using DNG Converter. The issue I'm having is with the thumbnails in Contact Sheets. I need PM+ to be able to render them using DNG Converter for specific DNGs. I don't like the idea of changing the preview image in the DNGs. This would cause the DNG preview to not match the image data.

I'm looking for a way to "flag" DNG files that causes PM+'s cached thumbnail in Contact Sheets to be rendered using DNG Converter from the image data instead of the preview stored in the DNG.

Does PM+ have a "Toolkit" where it would be possible for users to create extensions like this?

Offline Kirk Baker

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Re: Using PM+ with Negative Lab Pro
« Reply #3 on: Yesterday at 10:38:38 AM »
Tim,

I'm already able to successfully render previews in PM+ using DNG Converter. The issue I'm having is with the thumbnails in Contact Sheets. I need PM+ to be able to render them using DNG Converter for specific DNGs. I don't like the idea of changing the preview image in the DNGs. This would cause the DNG preview to not match the image data.

I'm looking for a way to "flag" DNG files that causes PM+'s cached thumbnail in Contact Sheets to be rendered using DNG Converter from the image data instead of the preview stored in the DNG.

Does PM+ have a "Toolkit" where it would be possible for users to create extensions like this?

You didn't mention which OS you're running Photo Mechanic Plus on, but if it is macOS, you can set up the RAW rendering to "Only render on demand" and you can use that to render these specific files by selecting the photo and pressing the "Toggle Render Quality" key (default is 'q').  After that, unless the DNG is changed, it should always show the rendered image rather than the embedded preview (at least until the cache is emptied, which you can also control).

No, there is no toolkit that can be used to create extensions.

-Kirk

Offline timhenrion

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Re: Using PM+ with Negative Lab Pro
« Reply #4 on: Today at 06:09:29 AM »
Hi Kirk,

Yes, I am on macOS 26.

When set to "Only render on demand", the 'q' key does, in fact, render the thumbnail(s) in question correctly in Contact Sheets! Unfortunately, those rendered thumbnails don't appear to "stick" in the render cache, and when I close/reopen PM+, the Contact Sheets revert to the unrendered thumbnail.

Also, is there a reason why "Toggle Render Quality" is only available when rendering is set to "Only render on demand?" I have rendering set to "Always render" because Lightroom Classic is my primary editor and I do a significant amount of RAW editing there, necessitating "Always Render". With rendering set to "Only render on demand", I have to manually render (via the 'q' key) every photo in preview windows that requires rendering.

My ideal desired behavior:
1) "Toggle Render Quality" is available in Contact Sheets if DNG Converter rendering is enabled, regardless of the "render" setting, to allow me to render groups of thumbnails in Contact Sheets as needed.
2) Rendered thumbnails should be cached and displayed in Contact Sheets until the underlying DNG file is updated, necessitating a "re-render" (although it would be nice if that happened automagically).

Question: Many PM+ operations (like "Toggle Render Quality") are not available from the application menus. I'm potentially thinking about automating PM+ actions and am wondering if other customers automate PM+ and how they access actions that aren't available via application menus.

« Last Edit: Today at 08:06:53 AM by timhenrion »

Offline Kirk Baker

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Re: Using PM+ with Negative Lab Pro
« Reply #5 on: Today at 09:39:57 AM »
Tim,

Please post a screen shot of both your Render Cache and Caching settings.  Use the 'Attachments and other options' link when you're composing your reply to this message and there you'll be able to upload your JPEG format screenshots.

Question: Many PM+ operations (like "Toggle Render Quality") are not available from the application menus. I'm potentially thinking about automating PM+ actions and am wondering if other customers automate PM+ and how they access actions that aren't available via application menus.

You can customize the keyboard shortcuts and if you use an automation tool that can simulate keystrokes, that automation should work.

-Kirk