New Features of Lightroom Classic 8.4 – Does GPU Actually Work Now?

In Master Photography Roundtable by Jeff HarmonLeave a Comment

Catching Up With Brent

As of this recording, I just returned from our 3.5 week family road trip. We drove over 5,500 miles (8,851 km). I had a printing workshop in Boise, ID, as well as a presentation to their club. We then went to Denver where I hosted another printing workshop. In Boise I had 18 present, and in Denver I had 12. Things were quite hectic with the 18 attendees and 12 was also a bit busy. We had club members bring printers as well so we could be way more efficient with printing, but we still had some bottlenecks.

I then also had a commercial shoot for a corporate aircraft charter company. I was going to also do headshots and brought all the gear for that but it ended up not working out with the schedule. I was only in the Denver area for 6 days and so we just did the planes, exteriors at sunrise and then a few interior shots. I’m also working on their website starting today, I’ll be redeveloping it using much of the current content but adding in a bit more.

We then went further to Missouri where we participated in a homesteading conference and then on to Illinois to visit friends. We rode the train into the city (Chicago) and then after that we fired home with a brief stop at Scotts Bluff, NE. I got a few shots there but I have yet to review them so we’ll see how it went. I’ll go into a lot more detail in my next episode of Latitude.

I’m working on a trip to India this December, Hawaii in March, Europe next summer, and school is starting in a few weeks so I’m a bit slammed with work right now. If I can work in some other printing workshops with clubs I’ll try and squeeze that into the schedule as well.

And it’s not too late to join my Oregon Coast workshop starting August 25, it’s really close here. But There’s still a few spots left if anyone is looking for a week of awesome photography on the coast. We’ll also spend two days looking at post processing and printing. I’ll have my printer there and we’ll spend the mornings and evenings shooting if we’re not too tired but the middle of the day for two of the six days will be spent analyzing our shoot, processing and getting some great prints and then we wrap it up with another full day of shooting for the last day.

Lightroom Classic 8.4 Updates

Brent, I have been teasing the Facebook group that I have started to see some interesting results from the Lightroom Hardware Testing Project I started a few weeks ago.  Especially with how that testing has gone with the recent release of Lightroom Classic 8.4. Before we get into that much, let’s talk about the changes Adobe made to Lightroom Classic with this release.  

You can read what Adobe has to say about all of the new features at

GPU Accelerated Editing

This is the big one, the update that is making waves through all of mainstream photography media.  I have seen a lot of articles talk about the fact that Adobe has said they have added GPU acceleration to editing photos in Lightroom Classic but I haven’t seen nearly anything on how well it works.  I will share a little more about this in the second half of the show, but let’s talk about the other updates first.

Batch HDR/Panorama Processing

Adobe added HDR/Panorama merging to Lightroom Classic almost a year ago back in October of 2018.  You could select several photos in the Library or Develop modules and then right click and choose to merge them and Lightroom merges them together into a very high quality DNG file that can be edited just like a native raw file from your camera.  Adobe was hearing from a lot of photographers that they like the HDR/Panorama merge feature but they need a way to do batches of merges instead of selecting one set of bracketed or pano photos and waiting for the merge to be done before selecting the next set of photos.

In this release Adobe has made it possible to batch merge HDR/Panorama photos with a couple of caveats.  

  1. First, the photos have to be organized into stacks in Lightroom.  You either have to select the set of photos and put them into a stack or you can try to have Lightroom put the photos into stacks automatically based on timestamps in the photos.  
  2. Second, ALL of the photos you are merging have to either be bracketed shots for HDR or multiple shots for panoramas, not a mix.  If you shoot bracketed panoramas, can’t use this feature and you will have to select those photos and merge them one set at a time.

Neither of use have tried out this new feature yet and wonder how things like the “projection” (a few different strategies for making a panorama merge look normal rather than skewed) and using boundary warp to use content-aware fill to add pixels where the shots didn’t provide them will be done.  

Library Module Performance

Adobe says they have made improvements to performance in the Library Module too, specifically the folders panel.  We will take whatever performance improvements we can get with Lightroom. Wish there was a little more detail from Adobe here but hopefully it means that if you use the Folders panel in the Library module to move photos around that it does that faster and without losing photos.

Just this week there was a user in the Facebook group who asked a question about what state things are in after an attempt to move photos using the Folders panel failed by pausing or something and they weren’t sure what had happened to the photos.  Our recommendation is to move your photos between different photos and especially between different drives OUTSIDE of Lightroom. Just safer to do it that way and then go in and tell Lightroom where the photos have been relocated.

Collection Color Labels

The ability to color label individual photos and see those color labels in Library and Develop modules has been part of Lightroom for a very long time.  Jeff uses color labels on individual photos as a unique way to mark the photos his clients tell him they like best and want to be fully edited (Jeff includes his clients in the culling process).  He uses star ratings for his own culling and to determine which photos are portfolio pieces and then reject flags to mark photos that aren’t being used after close inspection when culling has been done.

Brent also uses color label on individual photos to make which have been sent to agents (stock photography).  A few years ago he had more than one agent so he used a different color to indicate which agent each had been sent to.

With this 8.4 update to Lightroom Classic the Library Module now supports adding color labels to Collections, Smart Collections, and Collection Sets.  You can use the colors however you like, but one way might be to mark the status of the collection with a color. Maybe red for a collection you need to cull, yellow for one where you need to do edits, and green for those that have been completed.

This feature would only be helpful to photographers who use the collections feature in Lightroom, something that doesn’t seem to be very popular.  Jeff uses collections extensively, creating a new one for every client photo shoot he does. He was sort of “forced” into checking out how they worked so that he could get his photos to sync to the Lightroom cloud.  Today Adobe would rather have photographers use the new Lightroom application (not called Lightroom Classic) to have photos synced to the cloud far more seamlessly, but you can still do this in Lightroom Classic. There is still a little bit of cloud storage that is part of your Photography plan for this.  Jeff isn’t sure that this is going to be something that will really matter to his own workflow.

Brent uses collections occasionally, but not really part of his normal workflow, so this feature doesn’t really mean much to him.  More important to him than color labels for collections to help manage the editing tasks he has to do in Lightroom is knowing which photo he left on in his editing.

Filmstrip Index Numbers

The grid view in the Library module has had index numbers for a long time.  As you look at the photos in the grid view of the Library module (get to it by hitting the ‘g’ key) the first photo being shown has a 1 in the corner and then it goes up from there.  If you change the sort order of the photos whatever photo shows up first will then have the 1.  

With version 8.4 of Lightroom Classic those index numbers are also shown in the filmstrip that runs along the bottom of the Develop module as well.  Brent thought this might be more helpful than collection color labels to help him figure out where he left off in editing photos, noting down on a piece of paper what index number he ended on in the previous editing session.  So long as he doesn’t change the sort order that would work pretty well, though it wasn’t really a huge deal to switch to the grid view in the Library module and note it down from there.

Jeff hasn’t used the index numbers in the Library module in his workflow, which means this new feature isn’t really meaningful to him.

Export PNG

Lightroom has been able to import PNGs for a long time, now PNG files can be exported.  PNG files are a common image format that all of the computers in the world know how to use, like JPEG files.

Unlike JPEG files where some of the pixels from your original raw file are lost as it goes through a compression algorithm (called a “lossy” format), PNG uses a compression algorithm that reduces the file size significantly from your raw file but does it in a way that does not throw away any pixels (called “lossless”).  PNG also supports the definition of “transparent” pixels in an image where it will show whatever is underneath it as you use it with other images or put it on top of things on a web page.

Jeff is a little confused by this feature because even with the 8.4 update to Lightroom Classic there isn’t any way to define parts of an image that should be transparent.  The only use case he can imagine is round-tripping from Lightroom to Photoshop where you make parts of the image transparent and then go back to Lightroom to export to PNG. He isn’t sure why you wouldn’t just export the PNG right there in Photoshop.

Brent agrees with Jeff, not sure what he is missing why this would be something that is important and why customers using Lightroom Classic have been asking Adobe to do this.  Makes him wonder what he is missing, which Jeff readily agrees with.

Does GPU Acceleration Actually Help With Lightroom Classic 8.4?

Adobe first added some GPU acceleration a few releases ago but it wasn’t a feature that was involved in any of the image editing.  It was only used to make updating the screen go faster for high resolution monitors like those 4K and above. Read on to find out what the preference to use GPU enhancement was in prior releases and what it does in version 8.4.

GPU Was For 4K+ Monitors Before Lightroom Classic 8.4

I have long recommended that if you don’t use a 4K monitor to do your photo editing that you turn off GPU acceleration in the preferences of Lightroom Classic because the performance actually decreased for many using 2K monitors or lower.

Now that advice came from my own experience where all of the sliders, adjustment brushes, and radial/gradient filters in the Develop Module felt slower when I enabled GPU acceleration than when I didn’t.  I also had a large number of photographers share the same experience they had with smaller resolution screens.  

Those with 4K or larger screens seemed more 50/50 depending on the computer they had and the type of images they were working on.  My advice had been to do some editing with the feature both on and off and see if you can tell a difference one way or another. Since GPU acceleration didn’t seem to be a universal “fix” to performance with 4K monitors I have even said that photographers were better off with a 2K monitor so that they didn’t run into the bad situation where editing on 4K was bad no matter if they turned on the GPU acceleration or not.

The advice I had been providing was based on anecdotal information.  I had a “feeling” for how it worked for me and I had heard from plenty of photographers who had said how things “felt” to them, but none of it was quantifiable.  This, and a few other things, made me start the Lightroom Hardware Testing project a few weeks ago.  

I talked about it in a previous Master Photography episode when I talked about how much memory Lightroom needs, but to briefly recap I have decided I need to go through 51 different features in the Lightroom Develop module and use each feature for 1 full minute so that I can observe the impact the feature has on processor, memory, and GPU.  This would give me a more quantifiable way to measure what features in the Develop module need more resources and what impact things like different kinds of hardware, building previews, and megapixel size of raw files has on the performance of the Develop module.

GPU Is Finally Involved With Photo Editing In Lightroom Classic 8.4!

With this update Adobe says that they have now changed Lightroom Classic in version 8.4 so that GPU acceleration is involved with the editing features in the Develop module.  Again, prior to version 8.4 the GPU acceleration only helped make updating high resolution screens go faster. Now, with version 8.4, the GPU is supposed to be involved in the math that is going on to process those pixels of your images.  The question is, does it really work?

I have been furiously testing the update.  I have already spent more than 20 hours going through those 51 features in Lightroom Classic and punishing those sliders more than any photographer ever would.  I am about half way through the tests I want to run and am not ready to share more detailed information in this episode, look out for a Photo Taco episode coming soon where I will share more.

What I can share is that on both Mac and PC enabling GPU acceleration is no longer causing massively negative issues.  In my testing I have seen that prior to Lightroom Classic 8.4 if you enabled GPU acceleration when using a 2K or smaller monitor the amount of CPU needed as you used nearly all of the features in the Develop module rose dramatically.  In fact, with GPU enabled prior to 8.4 I could get both my PC and my Mac to thermally throttle (the computer processor go so hot from significant use it had to slow down how fast it operates) where it didn’t when GPU was disabled. With version 8.4 that is no longer the case for either PC or Mac!  There is no longer a downside with penalizing performance for lower resolution screens.

OK, so it doesn’t have the downside it used to, but does it improve performance?  I am not ready to really tell you that just yet, I have to get through more testing.  Early indicators are that it helps for some Develop module features, but you will have to stay tuned to find out more after I get through my testing.

Make sure the GPU in your computer is not on the blacklist by checking that here:


Jeff: Microsoft Raw Image Extension for Windows 10 ($0).  Makes Windows 10 show thumbnails of raw files from many cameras in File Explorer.

Brent: (going to rent a m4/3 camera probably, to see how it goes for my smaller format shooting)


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