Lightroom 6X slower to open a DNG than a PSD of the same file

[MarvinHeston]

OK, the upside of the Stay at Home order is time to figure how really bad somethings are, and by that I mean Lightroom/Camera RAW.  A couple of months ago I noticed that it seemed to be taking longer to open DNG files, so today I tested opening a DNG and a PSD of the same file. The PSD opening in under 5 seconds the the DNG take over 31 seconds.  WTH!

I'm running

• Lightroom Classic 9.2
• Camera Raw 12.2
• Photoshop 21.1.1
• Windows 10 64bit
• 64 Gigs RAM
• SSD drives (C:, running drive, and Cache drive are all M.2 SSDs)

I've attached/linked a real time video of the two different files opening to Photoshop. For this video

• Lightroom is open
• Photoshop is open
• I open the DNG file (13 Megs) - after it opens 32 seconds, I close it and
• Open the PSD file (327 Megs)  - opens in under 5 seconds

The PSD files is 25x larger than the DNG, so why does it take 6x longer to open the DNG file?

https://vimeo.com/404671466

[dj_paige]

File size is irrelevant here. Does the DNG have edits saved as metadata, including possibly local adjustments? This takes Lightroom time to crunch (which can be computationally intensive) and then display the edited DNG. The PSD file may not require any such intensive calculations.

[MarvinHeston]

Good Point.  To test I did another image.

RAW file - No Edits No Adjustments - 10.8 seconds

PSD file - No Edits - 2.3 seconds

Still 4.6 times slower to open a RAW file over a PSD.

Is there anything that can be done to speed this up? 

[dj_paige]

Lightroom has to render the image of DNG and RAW photos. In other words, it has to read the file and then do some crunching according to its internal algorithms, so you can actually view the image. With a PSD with no edits, it just has to read the pixels and display them, no other crunching, no algorithm to follow. So I doubt that there is anything you can do to make these times equal. Nor do I think you can get Lightroom to speed up the rendering of a RAW or DNG image ... (you can ask for fewer previews to be generated at Import, but that just slows things down later in the process).

[Jao vdL]

dj is right. importing a dng file and doing the initial calculations is way more intensive than a psd file. PSD files have a fully rendered preview in them that Lightroom can use straight away and there is no math needed to demosaic the data. When you read a dng raw file it has to be demosaiced, fast load data has to be generated and then the embedded edits applied before you can actually display. One thing to do to speed up import is to use embedded previews in the import panel and to not generate smart previews. 

[MarvinHeston]

Jao,

Thanks.  Import is not really a problem I can start that and walk away.  It's the loading the images into PS for edit at 30+ seconds per image that is making me nuts.  In experimenting, so far I have discovered the primary cluprits are Hightlights, Shadows, and Dehaze... all add 10 seconds to the opening of a file, even if only the smallest amount is applied.

[Jao vdL]

Just watched your video and realized you are not talking about opening the file in Lightroom but doing an edit in photoshop from Lightroom. What you are showing does not look normal at all. When I do an edit in Photoshop from a raw or dng file it opens in a few seconds, basically the same time as it takes to open a tiff or psd when doing an edit in Photoshop.

[Jao vdL]

Looked at whether applying any settings you mention and it makes no difference to how long it takes to open in Photoshop. About 2 seconds before the image shows up rendered in Photoshop from doing an Edit in with Photoshop already running. That's about what I would expect. Something is wrong in your setup it appears.

[MarvinHeston]

OK, I've uploaded the DNG (Grand Marnier-147.DNG) that I'm using. 

I'd love to have a few people to the following test and see the open times, especially helpful if you are on Windows 10 64, but happy to have anyones help.

Start with LRC open
Start with PS open

Import the file, then

from LRC open the file to PS Ctrl+E (CMD+E) - how long does that take (Mine 10.5)

from LRC apply -10 Highlights, 3 Dehaze, 10 Shadow - how long does it take to open the file now?  (Mine 33.5 to 35 seconds)

[Jao vdL]

I don't see the dng. Where did you put it?

[MarvinHeston]

Well here mud in your eye.  I exported the file as a DNG from lightroom and got this message

"The attacment's Grand Marnier-147.dng content type (applicatiojn/Octet-stream) does not match its file extension and has been removed"

[Jao vdL]

If you want to share a dng file, you have to upload a file to a sharing service such as dropbox, box, google drive, onedrive, icloud, etc. and post the link here. You can't attach or upload those on this forum unfortunately.

[MarvinHeston]

Apparently you can't upload DNG or CR2 files here.  Put it on dropbox

https://www.dropbox.com/s/dva1a291jnn8662/Grand%20Marnier-147.dng?dl=0

[GoldingD]

So, for PSD , edit in PS, you are editing the original, no copy to be created. For DNG, that not being an option, either LRC or PS (I think LRC) creates a copy, a copy that has to be converted from RAW to raster.

But, that does look like way to much time. Mine goes a lot quicker.

[Jao vdL]

David, just for completeness, when you edit in Photoshop wuth a dng, Lightroom sends the location of the dng file and a xmp sidecar that it creates in a hidden area that contains the edit settings. Photoshop is then instructed to open that original file (so no copy is made!) using camera raw with the edit settings in the xmp sidecar and to demosaic and render it. That should take only about a second to accomplish for most raw files. Photoshop than creates an edit buffer with the rendered data and presents that. Only when you hit save in Photoshop is the new file created and will Lightroom be instructed to import the new file.

[GoldingD]

This inquiry may seem odd, and I may not be able to reply. But, as a diagnostic step

In LRC, accomplish an export of the DNG to a PSD, not an edit in, just an export, how slow?

[MarvinHeston]

It takes about 3.5 seconds to export to a PSD to SSD

[Jao vdL]

OK took your Grand Marnier file and imported it. I reset all the settings (there already was highlights, dehaze and shadows applied). Edit in Photoshop was approximately 2 seconds to open. Then I applied -10 highlights, +10 shadows and +3 deHaze and did an edit in Photoshop and it took exactly the same time of abouit 2 seconds. 

I am editing on a macBookPro 15" with a 2.9 GHz 6-Core Intel Core i9 processor and 32 GB memory so a fairly beefy machine but for files like this I would expect it to take no longer than a 2 to 5 seconds on most machines.

[Jao vdL]

Do you by any chance have any virus scanning software running?

[MarvinHeston]

Running Malwarebytes right now.  I've got AVG shut off

I'm running

i9-7940 - 14 Cores

64 Gigs RAM

M.2  SSD for Programs, Data, and cache drives

nvidia Quadro M4000

So I should have comparable times to your machine.

[Jao vdL]

Try turning malwarebytes off too. Wouldn't surprise me if it is some utility such as that thinking that the sequence of events looks suspicious to malware detection programs.

[MarvinHeston]

Turning off MalwareBytes cuts about 10% off the load time, so now its

9.5 second raw no adjustments

20.78 raw with adjustments

Next?

[Jao vdL]

And that machine should do this much faster than mine! 14 cores vs 6 and my ssd is similar speed but the opening time should mostly be dominated by doing the demosaic and running the camera raw engine which is mostly cpu bound for this operation.

[MarvinHeston]

You got me on the right path!!!  

I shut off Acronis and now my file opens in 1.9 - 2 seconds.  YEAH!  

Now I just need to decide if I want to have Acronis off, or if it has exclusion list that I can add LRC to.

Thank you so much for your help and patience.

[Jao vdL · Accepted solution]

Aha! of course a backup utility could do this too if it tries to backup and locks one of the files that is needed for Photoshop to read it.