# Practical image size limits



## LRList001 (Aug 12, 2017)

1/  Does anyone know the practical image size limits in LR5?
I have LR5 and opened an image of around 3G pixels.  Apart from LR having weird display problems prior to the actual import process, once loaded LR ran fine, it was fast and responsive, using around 3.5GB RAM.  However, it was not possible to export the image in any format, so 100% useless.  Jpeg caused LR to give an out of memory message (at any output file size) and DNG caused a very hard crash of the OS.

2/ Is LR6 any better?

TIA


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## Jim Wilde (Aug 12, 2017)

I'm surprised you could get LR to import a file that large.....there's supposed to be a maximum file size of 65,000 pixels on the long edge, or 512mp total (whichever is the smaller). Might explain why it's struggling to export a file that large.

LR6 has the same restrictions.


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## LRList001 (Aug 12, 2017)

Jim Wilde said:


> I'm surprised you could get LR to import a file that large.....there's supposed to be a maximum file size of 65,000 pixels on the long edge, or 512mp total (whichever is the smaller). Might explain why it's struggling to export a file that large.


Thanks Jim
I had better check my maths re the size, the file is around 2GB on disk.  Whatever, I'm close to the 65,000 limit.  I forgot to mention that I'm running a 64 bit OS with plenty of spare memory.  My questions remain though:
1/  What is a practical file size limit (not the theoretical limits) (I can trim the image down, but as it takes a lot of processing time I'm not in the mood for a lot of experimentation, I'm trying to get this done(!!))
2/  Is LR 6 different?

PS My maths, 65,000 x 65,000 is 4G, so I am under that limit, but way over the 512mp limit.  512mp is a bit out of date now.  Is there any chance that although LR is 64bit, it has a 4GB limit on any one address space?  I guess I can try cutting down to the 512mp 'limit' as a first attempt at finding the practical limit.


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## Jim Wilde (Aug 12, 2017)

I think you're getting mixed up regarding pixel size and file size. AFAIK, the physical size of the file is not relevant (though I've a fuzzy recollection that 2mb file size used also to be a limitation, but I can't find a reference to that in Victoria's Missing FAQ book), it's purely the pixel size and count that are the limits. So if it's less than 512mp, and the long edge is less than 65000 px, it should be fine.

I have a panorama that I created in LR6 which is approx 50,000 x 5200 px, which imports and exports fine (which is as expected as the pixel count is only 261mp and the long edge is less than 65,000 px). So what are the pixel dimensions of the file that you're dealing with?

And LR6 has the same limitations.


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## LRList001 (Aug 14, 2017)

OK. Ignore all previous data and lets start again.

LR5.7.1, 64bit W10, at least 24GB spare RAM.  SSD with ample free space.  Empty (new) catalog.
These are all the same pano.  Memory usage is as per task manager.
Image 1: TIFF, probably not compressed, 48bit bit depth, 44,770 x 6484 = 290,289,000 pixels 2,099MB on disk  
Image 2: TIFF, no compression, 24bit bit depth, 44,770 x 6,484 = 290,289,000 pixels, 871MB on disk
Image 3: TIFF, zip compression within the TIFF 24bit bit depth, 44,770 x 6,484 = 290,289,000 pixels, 451MB on disk (should be identical to #2).

Starting with #3 in an otherwise empty folder.
Import #3 by dragging into LR.  Roughly 0.5s and thumbnail shows image.  Import ~1s and imported.  Develop, bit of a pause 2-3 seconds and 1:1 preview on screen.  Sharpen, change contrast.  All instant response.  Export to jpeg, sRGB, 76% quality. LR memory use climbed to 9GB and dropped back to 4.5GB  Took about 5 seconds.

Move #2 to same folder and import as before.  Much the same performance until rendering 1:1 preview, now a distinct pause maybe 6 seconds. Develop performance: instant.  Export to jpeg as before.  Took a bit longer.  Memory started at 6.5GB, climbed to 10GB dropped to 9.5GB, climbed to over 11GB and then went to 8GB when finished.  (We know that LR is poor at handling cached memory)

Lets try #2 in a new catalog.
Restored import and 1:1 performance to match that of importing #1 (ie quick).  Export started with 2.5GB RAM climbed to 9.5GB dropped back to 4.3GB.  (What is all that extra RAM needed for, the export has finished?)

Given that the first attempt with #2 was compromised by importing #1, lets have a third new catalog.  RAM at 1.5GB.
Clear those two images from the folder so only the 48bit one is visible to LR.
Noticeable delays, but nothing too bad.  Even though the 1:1 preview was claimed to have been built, it still took several seconds for the 1:1 view to be displayed.  Memory at 2.6GB  (Is LR 48bit?)
Export, memory climbed to over 11GB and dropped to 4.4GB, succeeded.

From these experiments it would seem that a clean LR with a clean catalog can manage an image this big, but I have no intention of trying it with my usual catalog.  Perhaps the moral is start LR again before working on larger images, and give up hope with any of those 10+gp images.

Regards

Thanks Jim for the LR limits and the LR6 being the same as LR5.


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## LRList001 (Aug 14, 2017)

I can add a PS to this.  I have now re-opened my regular catalog and memory use stabilised at around 800MB then climbed slowly to just over 1GB.  I'm not doing anything you understand.  There is one image on screen at 'fit' scale.  The new catalog with no images at all in it opened at 1.5GB.  Whatever.  Going into the library, clicking around a bit and then editing an image has managed to drive memory use to 1.6GB, took some doing before I exceeded the RAM requirement of LR 5.7.1 with no images at all.  On every occasion I am using 'open recent catalog' to switch.

More oddities.  Catalog #1's directory is big, many MBs of preview.  Catalog 2' and 3's directories are a few KB.  Just where those previews went, I have no idea.  A search of the SSD for any 'today' lrprev file only finds the ones from the first catalog.


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