Eric Stevens
But it's not the same as the file you would - say - send to a printer.

Sandman
It could be, sure. It's an ordinary JPG, and most printer drivers can handle them just fine. Again, you don't know what you're talking about.

Eric Stevens
I would send my best file to the printer, not a highly reduced JPG.

Sandman
They're not highly reduced, Eric. You are confused.

Eric Stevens
I have looked at the actual file sizes. I *know* they are reduced.

Sandman
Here's some education for you.

In Lightroom, you the user can select whether standard previews should be 1024, 1440, 1680, 2048 or 2880 pixels large, you can also set the preview quality to low, medium or high.

BUT, Lightroom *always* use a 1:1 preview for the file you are working with. You can select for how long these 1:1 previews should be kept around, but for the files you're working with - and would send to a printer in this hypothetical scenario - the preview file is the exact same resolution as the original file. Always.

You really don't know anything about Lightroom and should keep far away from discussions about it.

Depends on how you export it. If you export it as a low-res highly compressed JPG, it can use the preview file. Chances are that it doesn't, but it certainly could, since the preview file *is* the current pixel data of the image.

Eric Stevens
So what happens when you want a high quality TIFF of the same size as the original file? Do you expand by resampling your low-res highly compressed JPG?

Sandman
Only if the original file is a low-res highly compressed JPG, which of course it could be.

And TIFF's aren't "expanded" or "resampled". They're - like the preview's - a 1:1 copy of the original file, the difference being that TIFF can support a higher bit depth.

Again, you know nothing about these matters. You would do best to just sit quiet.