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Preview strategy for 27" iMac (5K)

Joined
Sep 28, 2008
Messages
574
Location
Tacoma, WA
Lightroom Experience
Advanced
Lightroom Version
Classic
Lightroom Version
9.4
Operating System
macOS 10.15 Catalina
I made some decisions several computers & monitors ago about previews, and I'm wondering if making different choices makes sense now. What brings this to mind is that my previews file is about 80GB without any 1:1 previews (I discarded the previews.lrdata file—which AFAIK holds only the standard and 1:1 previews—and rebuilt the standard previews to see how much room they take up), and I am about to embark on a scanning project for my pre-digital images, which will increase the number of images in my catalog (now about 20K). The internal SSD, where I keep the catalog for speed purposes, is filling up to the point at which it will start to slow down (I've read that keeping an SSD to ~70% capacity is better for performance).

I have had standard previews set to Auto (which for a 5K monitor means 5120px) and High quality. 1:1 previews are set to delete after 30 days. I use smart previews in the Develop module, and I generate smart previews and 1:1 previews at import.

I (reread) a variety of threads about how LR uses & generates previews, and this tutorial Victoria wrote on the subject.

This is what I'm asking myself:
  1. Is Auto (5120px for me) really a useful size for standard previews in my use case? Should it/could it be smaller? I almost never look at an image full-screen in the Library. Because of the size & resolution of the 27" 5K monitor, looking at an image in Loupe mode with the left and right panels visible is almost always enough for me to make culling & rating decisions. And, because I have an external monitor as well, when I'm culling & rating I have the second monitor (1920x1200) set to Loupe and the 5K monitor in Grid view. So, I'm wondering if Auto is the right setting for standard previews, as I almost never would need a 5120px preview on the 5K screen.
  2. Should I use Medium vs High quality standard previews? When I decided long ago to use High quality, I suspect my thought at the time was "the higher quality the better," but does that really make sense for culling & rating purposes (and I mostly likely did not know back then that Develop doesn't use the standard previews).
  3. Should I stop using smart previews in Develop? I set LR to use smart previews in Develop (I always edit on the 5K monitor), because on older equipment there was a delay that I didn't like while LR built the 1:1 preview as I moved into the Develop module. But, for a 5K monitor, a 2560px smart preview is significantly lower resolution that the size of the image that is displayed in Develop. If I understand correctly what LR is doing with this setting, it is taking the 2560px smart preview and just enlarging the pixels to the size that fills the Develop module's viewport. If I'm right about this, am I making editing decisions on a lower resolution version, and so would it be better to stop using smart previews in Develop?
  4. Should I stop generating 1:1 previews on import? Given my workflow, I'm thinking that generating 1:1 previews on import is silly, as the standard preview is already larger than the size at which I typically view images in the Library in Loupe mode.
Of course, I may still misunderstand things about how LR generates and uses various previews...
 
Joined
Jun 20, 2009
Messages
16,581
Location
Houston, TX USA
Lightroom Experience
Power User
Lightroom Version
Cloud Service
I do the following:
Medium size Previews on import and skip the 1:1 until LrC requires them.
After import, I cull so that I minimize the Previews created.
I create smart Previews but that is another large preview folder created by LrC.


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Joined
Nov 5, 2017
Messages
856
Location
UK
Lightroom Experience
Power User
Lightroom Version
Classic
I do the similar to Cletus, but I set size to Auto. I'd suggest Medium Quality (reduces size of previews) as if you want to zoom in or work in Develop it'll make 1:1 anyway.

To understand the loading logic and when different previews are used, look at the charts on pages 461 & 464 of your Classic book, that may help!
 
Joined
Jun 20, 2009
Messages
16,581
Location
Houston, TX USA
Lightroom Experience
Power User
Lightroom Version
Cloud Service
Actually, I was reciting my Import setting from memory. I no longer use this since I started using a 48mp Nikon Z7.
Here are my current import settings CORRECTED:
Build Minimal Previews
I no longer build Smart Previews since the develop Time saved is minimal and I only work on my desktop with the original files available.
 
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