Export w/ original and Smart Preview

[solo-nko]

So there is an option in LR Classic's Preferences, a checkbox labeled "Use Smart Previews instead of Originals when image editing."  My understanding from Adobe's tutorial pages is that with this option checked, you can edit and export photos with just the Smart Previews, even if the original is disconnected.

My question though, is if you have this option enabled, will Lightroom still use the Smart Preview for editing and exports even when the original photo(s) are connected?

[DdeGannes]

The Smart Previews are useful for carrying out edits which should be adequate for viewing on-screen. If you require high/ full resolution export images you require the original files. If you use Smart Previews to export and resize to a higher resolution then guess what? Reduced quality.

Smart Previews are 2540 pixels on the long side.

[Theresa J · Accepted solution]

Lightroom Classic does not edit the photo itself regardless if it is connected to the catalog or not. So the smart preview option shouldn't make any difference for editing, unless the photo is offline. If the photo is offline you won't have the option to edit it. 

When you export with the photo offline, it will use the smart preview and limit the export size to the size of the smart preview. If the original image is available, you can export a larger size file. The smart preview is not going to get in the way of that.

[richardplondon · Accepted solution]

Whether export sizing will actually be constrained to reflect the use of a smart preview, depends both on the availability of the original, and on whether "Don't Enlarge" is checked in the Image Sizing settings for the export.

Whenever the original is not available but a smart preview is, a warning message notifies you that only that limited quantity of picture information will be used towards export processing. You can still select whatever export pixel dimensions you choose, and (if "Don't Enlarge" is turned off) LR is just as ready to upsample, as it more typically would be to downsample. The available source / the output settings are two independent upper limits, on the picture detail within the output.