Export Unexpected file sizes from specific settings

[Nicky H]

Lightroom Version Number

Lightroom Classic 8.1

Operating System

1. Windows 10

I recommend to a group of people providing images for a project that they export at 4000 on the long side, 300 ppi, quality 80 or higher to provide print suitable images. When I export at these settings from files my 16-18Mb raw files, I get jpgs 6-9mb depending if Dialogue box "Resize to fit" is ticked or not. When others send me files which are from equally large or larger raw files, I often get file sizes of a few hundred kb only. I then have to query their export settings in case they have uploaded web quality by accident, or if they are using something like jpgMINI to retain quality but reduce file sizes. If they are providing correctly exported files, and not using jpgMINI, why are some sets of files exported so very small? I have yet to send one for a test print but this would be my next step.

This seems to be becoming increasingly common in recent months. Checking with the photographer every time it crops up is very time consuming. I can see pixel dimensions and ppi in Br, but can't check where the quality slider was. Why is Lr not giving reasonably consistent results from a given set of settings? It seems to be increasingly common in recent months. Have Adobe made changes? I can only say what version of Lr I am using, not the other contributors, but I expect their versions to be fairly recent as they are all working professional photographers.

Thanks in anticipation.

 

[Johan Elzenga]

File sizes of JPEG images mean very little. Some images compress well, other images (lots of detail, noisy) are hard to compress. Judge the images, not the file sizes.

 

[Hal P Anderson]

Judge the images, not the file sizes.

Exactly. How do they look at 1:1 on your monitor? If the JPEGs are really too compressed, you ought to be seeing highly visible compression artifacts.

 

[Nicky H]

We speculated on this with a very high key image, images at the opposite end of the scale were even smaller. I worry they will not print adequately - 300kb files to 30" canvas?? I can't judge the images suitability for print without ordering a print. They display fine, but that doesn't reassure me.

 

[Nicky H]

Exactly. How do they look at 1:1 on your monitor? If the JPEGs are really too compressed, you ought to be seeing highly visible compression artifacts.

Good point, I'm not seeing such.

 

[Johan Elzenga]

We speculated on this with a very high key image, images at the opposite end of the scale were even smaller. I worry they will not print adequately - 300kb files to 30" canvas?? I can't judge the images suitability for print without ordering a print. They display fine, but that doesn't reassure me.

If they look fine, they should print fine. I don't know any printer that deliberately ruins a print because it thinks the file size is too small.

 

[Nicky H]

Thanks folks, I rarely print these days, I've been accustomed to at least a few Mbs for 300ppi files so this sharp decrease in file sizes from others worries me when my exports with the same settings are staying pretty much the same as they've always been.
Nicky

 

[LR_JD]

ppi actually means nothing for digital files.
Pixel resolution and compression are what affect images.

ppi only itself only does one thing (although many mistake it as a quality indicator). ppi sets a print size for any given pixel resolution.
You can check this by saving any image at different ppi. So long as the pixel resolution remains consistent the image size will remain the same (no matter ppi)


As said above by JohanElzenga it's all about compression and the image itself as to how simple it is to compress. For example a plain white background with a subject can be very simple to compress resulting in pretty small images.

 

[prbimages]

Still, a "few hundred kb" does sound small for a 4000-pixel wide image. Do you notice any commonalities among the images giving you small file sizes? For example, large blocks of a single colour (skies, building facades, etc.) will often compress much more than fine detail (e.g. lots of trees with leaves in a landscape). The amount of sharpening that the photographer applied will make a difference too - something that is slightly soft will usually compress more than something with lots of areas of sharp contrast. Note that sharpening can be specified in the export process from Lightroom, as well as in the Develop module. Exporting with "high sharpening" can easily increase the file size by 50% compared with "no sharpening".

 

[Dan Marchant]

have you confirmed that the file you received is the same size as the file they exported? One common cause of problems like this is email software, rather than Lightroom. Some packages may resize images and the user doesn't always realise.