Lightroom keeps reloading images even if 1:1 previews have been generated

[chrvi]

Hi,

I would think that once I create 1:1 previews, there is no reason for Lightroom to load this image again (which it would normally do if previews have not been generated). If I make an adjustment to the image later, Lightroom is said to update the image preview based on the up-to-date state of the image (including applied adjustments). I would suppose that Lightroom creates this updated preview once (as the adjustment has been done and I zoom in the picture to 1:1 level) and then the preview remains created so there won't be any reason to reload that image when I zoom to it.

Nevertheless, if I zoom to the 1:1 level and scroll through the images, Lightroom doesn't show the 1:1 versions of the images immediately but it takes some time while "Loading" label is displayed at the bottom of the image being loaded.

The question is - why would Lightroom "load" the 1:1 versions of the image again and again if the 1:1 previous have been generated? (it looks like it always generates an updated image preview including all adjustments over and over) At this stage I can't see any difference between viewing images at 1:1 level for which previews have been generated and images for which previews have not been generated.

It almost looks like the time it takes to "Load" the image is, in fact, time Lightroom needs to get the preview file from the file system (i.e. it's not time spent on creating the preview again but rather opening the already existing preview).

In such case I don't understand why it should take so long though... Neither any of my CPU cores, neither my HDD or RAM seem to be 100% utilized (usually they're at about 15% of their capabilites) while I wait for an image to be "loaded".

What do you think? I would like to cut the time needed for the image to load but in fact I don't know what in this case may be the bottleneck and whether I can configure something to improve the load times. 

Thanks.

[DdeGannes]

Just a hint. The previews are utilized by the Library Module for you to browse through your files there. When you are working in the Develop Module, Lightroom works with Original imported files or Smart Previews if built and the Originals are not available.

[MacTavish24210287vnpr]

3 years later and the problem is still there. bravo adobe.

[Jao vdL · Accepted solution]

@DdeGannes gave the correct answer already in 2019. 1:1 previews are only used in Library, so when you step through images in Develop (where you see the loading text), those cannot be used and it loads the raw files. So this is not a bug or problem, it simply does not apply. If you have 1:1 previews you will see that in Library you can zoom to 1:1 without any delay.

[MacTavish24210287vnpr]

I'm sorry but it's simply not true. If you have any high mega pixel camera, like A7R IV or GFX 100S, rest assure even if you've built the 1:1 previews and DO NOTHING ELSE, it still loads and waits in Library module when zoomed into 100%.

[Jim Wilde]

Not on my system, it doesn't. I've just downloaded half a dozen full resolution raw files from a GFX 100S, imported into LrC, built 1:1 previews, then zoomed to 1:1 on each of them. No "loading" messages, time to zoom I estimate at around 1/10th of a second, i.e. pretty well instantaneous.

Running an M1 Mac Mini with 16GB unified memory.

[Jim Wilde]

On my late-2013 MacBookPro, also with 16GB memory, it is obviously slower than my 2021 Mac Mini. It probably takes a second or so to load the 1:1 preview first time, but subsequently it's instantaneous (expected, as it's now cached). No "loading" message.

Overall, though, considering the age of the system and the size of the files, I'd regard that as very acceptable.

[MacTavish24210287vnpr]

I think you should try a fast random 100% zooms to check focus across, like, >100 images, as that is a very common situation for photographers to do mass culling to remove the misfocused images. In short, it's usually just 3 times faster to switch to develop module to check the focus instead of using the 100% preview in library module, because it always loads in previews in a very sluggish way. Even with 1:1 previews generated.

[Jim Wilde]

Sure, tried that with 200+ 45mp files from my Canon R5. Moving quite quickly through them in Library (after building the 1:1 previews) and zooming each one to the 1:1 view, that was as quick at the end (i.e. instant) as it was at the beginning, which is no more than I would have expected. So in your workflow, how quickly can it zoom to 1:1 with the first few images, and how quickly does it zoom after your >100 images? What files are you processing? I suppose doing it with 102mp files from a GFX might put more pressure on the system Ram, so that might translate into a slowdown the further you proceed through the collection.....but initially it should be instant.

But 3x faster in Develop? That shouldn't be possible if the 1:1 previews have been built and you cull in Library. The best you should be able to hope for in Develop is parity with the 1:1 zoom in Library with 1:1 previews.....and that would only be possible if you slowed down the culling speed to allow time for the pre-caching in Develop stay ahead of you.

FWIW, I gave up building 1:1 previews on import when the embedded preview workflow was introduced (Classic V7?). Fortunately I use mainly Canon cameras, which usually embed a full-resolution jpeg....these are perfect for high-speed culling in the Library, a process which I can start even before the Import has completed. No need to then wait for previews to be built.

[Jao vdL]

Yeah that makes no sense. If there are actually 1:1 previews, stepping in Library is light years faster than stepping in Develop. I also currently just use embedded previews on import as that is again light years faster on the import step and those work perfectly for focus check at 1:1. Almost every camera out there embeds 100% scale jpeg previews in the raw file and those work great and are basically immediately available upon import.

[Jim Wilde]

 Almost every camera out there embeds 100% scale jpeg previews in the raw file and those work great and are basically immediately available upon import.

Sadly, there are a few manufacturers that don't embed full-size Jpegs....Fuji don't, and Olympus didn't when I last used them. So the downloaded GFX 100S files that I tested don't, though the embedded preview seemed a good size, so it might still be big enough for most focus-checking purposes.

[Jao vdL]

Good to know. I am only intimately familiar with Nikon, Sony and Canon files myself.

[MacTavish24210287vnpr]

For Sony, at least for the R series, at least for Lightroom running on both PC and Mac, high end or low end, it's not loading the full size embedded preview, and it's taking seconds to render full size previews as well. Even if a full size preview is pre-rendered via the library commands, it's still taking a couple seconds to load in. I know it doesn't make any sense, but it's happening everywhere, and that's exactly the reason that I'm not happy with it.

[JohanElzenga]

There is no problem. Library previews, including 1:1 previews, are 8 bits jpegs. Believe me, you would not want Lightroom to use these in the develop module!...

[richardplondon]

In Catalog Settings, there is an expiry option for 1:1 previews

after which period (since last edit IIRC) the disk space gets reclaimed. Could that be it?

IIRC the trigger for having (or later re-making) a 1:1 preview is: zooming right into that image in Library. For those images not inspected at 1:1 in Library, such a preview may never happen in the first place, let alone later updates to this.

Zooming to 1:1 in Develop, is unconnected. And making a new edit will not necessarily trigger (re)calculation of 1:1 Library preview - until you go back to look at that - just updates to the normal Library preview and the thumbnail, AFAIK.

Personally, it is entirely Develop where I use 1:1 zoom, and that is generated live as you go. Develop does use an intermediate (so called ACR) cache, so doesn't always need to go right back to the Raw data. Hence for performance of switching between images in Develop at 1:1 zoom, the location of that cache (on fast storage is better) as well as sufficient sizing, may be worth a look especially if some images are very high-res. 

I do find standard Medium previews to be ample for Library. Analogy: at the counter of a book library, staff are only really looking at the barcode / spine label / whatever of each book, and its overall condition. The book's detailed contents simply are not read in this context.