Smart Previews and small originals

[bradm48868034]

One of my camera's generates really small images: 1080 pixels square; but not all images in the catalog are that small. If I set the catalog to generate all smart previews so that I can edit off line, will it upscale those images?  Should I set small images to 1:1 and use smart only for the larger images? 

Thanks!

[dj_paige]

What software are you using? What version NUMBER?

If Lightroom Classic

You say: "One of my camera's generates really small images: 1080 pixels square; but not all images in the catalog are that small." This, as far as I know, is impossible in Lightroom Classic for originals that are 1080 pixels square. Please show us screen captures of what you see that indicates not all images in the catalog are that small. Add the screen captures to your reply by clicking on the "Insert Photos" icon; do not attach files.

[bradm48868034]

To clarify: The original images from one of my cameras are only 1080 sq. Images from other cameras are in the multimegapixel range. 
Smart Previews are 2560 (?) on the longer side - larger than the original.

[richardplondon · Accepted solution]

Smart previews are usually to a different resolution, but more importantly are different in the nature of their content and in where they are stored. IMO to the extent  all images can undergo essentially the same workflow, so much the better.

.Whether or not these small images will create a smart preview despite their low resolution; you are best placed to find out. That status then shows under the histogram. I see no issue with working from a SP that happens to be of greater resolution than the original image, assuming that is how it works - certainly you'll be no worse off, than when a SP happens to be of lower resolution than its original.

[bradm48868034]

Interesting take. I agree with the workflow comment. What may become an issue is a Smart Previews.lrdata file that may be bigger than the collection of images themselves! I've set it to generate smart Previews for all. I'll let you know what happens. Thanks. 

[bradm48868034]

Previews: 1.33 GB

Smart Previews: 9.5 GB

LR Catalog File: 923.9 MB

Image Collection Itself: 18.95 Gig  (57k images  at 1080 sq/<200KB, 4k others) 
So, 50% of the size of the originals; presumably of 1/1 previews as well?
Next question is how offline edits on an oversized preview apply to a smaller original. 

[richardplondon]

As far as I know, localised edits such as a radial gradient as well as crop size and angle and other transforms, all work in terms of % of the image area as seen. So work the same pictorially speaking, regardless of a different number of pixels being used to show that picture. Same for masking (also image-resolution-neutral AFAICT).

This can be easily shown: import a JPG, apply edits, outside of LrC substitute in a lower or higher resolution version of this same JPG under the same filename, return to LrC and review what's happened with the previous edits.

I suppose the pixel specifics of sharpening and noise reduction cannot be so resolution independent: for example, sharpening is to a certain pixel radius (original pixels) so may not be accurately previewed. That said: it won't be either, when working with the original at a non-1:1 zoom. Some allowance is needed for circumstances..

[bradm48868034]

All great info, duly noted and thanks!

As an experiment I ran 100% Smart Previews on another catalog. 

Previews (auto) : 61.15 GB

Smart Previews: 35.83 GB

LR Catalog File: 476.1 MB

Image Collection Itself: 296.45 Gig for 75k Items

Solved! 

Thanks again. 

[HooliganImages]

This actually is an important question if one is using Adobe Portfolio.  Some have said that if the image is under 2560 pixels on the long edge the Smart Preview is that size.  I did a test which suggests that may be true but have yet to confirm that in any way.  

You can look at the images here and look at the third row which is a 1/4 crop rougly 2067 pixels on the long edge.  Compare the second and third images - sync from LRc using a smart preview and jpg uploaded directly.  

https://hooligansimagery.myportfolio.com/resolution-test