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Are full-size and smart previews regenerated and saved after develop edits?

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If I make edits in the Develop module, obviously the display changes to reflect the edits. I presume that what I'm seeing in the Develop module is a full-size preview, so Iis this full-size preview saved so that the next time I open the image (either in Loupe or Develop) LR doesn't have to regenr

What about the smart preview for the photo I've edited? Is the smart preview also regenerated to reflect the edit(s)?
 
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Smart previews aren't really previews, they're a proxy for your master files, hence they are never regenerated.
 
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The answer to both your questions is no. Hal has already explained about the Smart Previews, but the preview that is used in the Develop module (if you've not elected to use the Smart Previews for editing) is a temporary preview generated each time you open an image in that module. Library previews are not used for editing purposes, so it therefore follows that as soon as you make an edit in Develop any existing Library preview for that image is now out-of-date and so is deleted. Thumbnail previews are recreated on the fly as you make edits (so you'll immediately see the effect of the edit in the filmstrip and navigator), but the Standard preview and 1:1 preview are not. However, the next time you view that image in the Library module (be that in the Grid, Filmstrip or Loupe), the Standard preview is automatically and silently updated, but the 1:1 preview is not and thus has to be rebuilt manually if needed.
 
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Previews and Smart previews always reflect the most current set of edits. Smart Previews are lossy DNGs and actual pixels the are displayed on the screen are saved as a LossyDNG to replace the previous Smart Preview. Regular Previews are generated in the sizes used by LR (including 1:1) Lightroom may not generate a new preview in the size requested UNTIL the size is requested. Any out of date previews are marked obsolete so that LR will know whether to regenerate a fresh preview when requested.

You can always select one or more images and build fresh ones in the {Library}{Previews} sub menu for either standard Previews or Smart Previews
 
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Smart Previews are lossy DNGs and actual pixels the are displayed on the screen are saved as a LossyDNG to replace the previous Smart Preview.
Nope. As others have said, smart previews are proxies for your raw files. Just like raw files they remain untouched. What you look at on screen are regular previews and these are the ones that get updated with each edit.
 
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Just like raw files they remain untouched.
OK. I think I am getting a better unserstanding myself. Smart DNGs are those sent to the cloud as proxy for the actual original image. These get updated and transmitted when ever a Classic image is sync'd to the cloud. They are proxy DNGs that are unedited originals with the latest edits being the adjustment parameters which are also sent along. Smart Previews are local unedited EGB original previews with the latest edits being the adjustment parameters which are applied when ever a display image is needed. New Previews and Smart Previews can be generated/regenerated anytime the function is invoked from the {Library}{Preview} submenu
 
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Correct. Adobe, famous for always trying to be as confusing as they can be, called them ‘smart previews‘, even though they have nothing in common with previews. ‘Smart proxies’ would have been infinitely better, but hey, then people might understand it! :)
 
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They are proxy DNGs that are unedited originals with the latest edits being the adjustment parameters which are also sent along. Smart Previews are local unedited EGB original previews...
I think they are actually the same, i.e. proxy DNGs. Remember that if a Smart Preview already exists when you start to sync an image to the cloud, the existing Smart Preview is simply copied to the cloud, i.e. it is not generated anew, ergo they are technically the same .
 
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I think they are actually the same, i.e. proxy DNGs. Remember that if a Smart Preview already exists when you start to sync an image to the cloud, the existing Smart Preview is simply copied to the cloud, i.e. it is not generated anew, ergo they are technically the same .
This thread has been enlightening. Prior to this thread, it considered Smart Previews and Smart Cloud proxies to be similar to regular previews. That is processed. I understand now that they are unprocessed RGB files in some DNG wrapper.


Sent from my iPad using Tapatalk
 
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Wow...I had no idea I would start such an interesting discussion!

Let's see if I understand the "final answer"...

1. OK, so Smart "Previews" are really lossyDNGs created from the original RAW files. They never change. I presume that they are NOT the same as what happens when one chooses "Convert to DNG" from the Library menu, because the latter is a lossless DNG while Smart Previews are lossy DNGs...yes?

2. 1:1 Previews are generated as needed. I have been generating 1:1 previews upon import because I read someplace where doing so would speed up the rendering process when I go into Loupe or Develop. Yes? If I've made edits on an image and am NOT using Smart Previews for edits, then the 1:1 preview will be regenerated as I make these edits. BUT, if I AM using Smart Previews for edits, then the 1:1 preview will NOT be regenerated until/unless I go into Loupe mode and thus need to use the 1:1 preview. Do I have this right?

Thanks, as always, for the great help from folks on this board.
 
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1. OK, so Smart "Previews" are really lossyDNGs created from the original RAW files. They never change. I presume that they are NOT the same as what happens when one chooses "Convert to DNG" from the Library menu, because the latter is a lossless DNG while Smart Previews are lossy DNGs...yes?
Yes. In addition to being lossy rather than lossless DNG's, smart previews are also on 2560px long edge, whereas the originals may be much bigger.

2. 1:1 Previews are generated as needed. I have been generating 1:1 previews upon import because I read someplace where doing so would speed up the rendering process when I go into Loupe or Develop. Yes?
1:1 previews are generated as needed in the Library module. They're not used at all in Develop. They're useful to render in advance if (and only if) you zoom into most photos in the Library module before you start editing, for example, when picking your favorites.

If I've made edits on an image and am NOT using Smart Previews for edits, then the 1:1 preview will be regenerated as I make these edits. BUT, if I AM using Smart Previews for edits, then the 1:1 preview will NOT be regenerated until/unless I go into Loupe mode and thus need to use the 1:1 preview. Do I have this right?
No, regardless of whether you're using smart previews or now, the 1:1 preview are not updated until you zoom in the Library module again.

So in summary, standard and 1:1 previews are used for fast viewing in the Library module, whereas Smart Previews can be used in place of the original in the Develop module.
 
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1. OK, so Smart "Previews" are really lossyDNGs created from the original RAW files. They never change. I presume that they are NOT the same as what happens when one chooses "Convert to DNG" from the Library menu, because the latter is a lossless DNG while Smart Previews are lossy DNGs...yes?
Yes.

1:1 Previews are generated as needed. I have been generating 1:1 previews upon import because I read someplace where doing so would speed up the rendering process when I go into Loupe or Develop. Yes?
Not entirely. Generating 1:1 previews during import is useful if you typically use a zoomed-in view when making the initial culling decisions in the Library module, but they are simply not used in the Develop module. Checkout the flow-chart diagrams on pages 461-464 of your Missing FAQ book for a full description of the preview loading logic in both Library and Develop modules.

If I've made edits on an image and am NOT using Smart Previews for edits, then the 1:1 preview will be regenerated as I make these edits. BUT, if I AM using Smart Previews for edits, then the 1:1 preview will NOT be regenerated until/unless I go into Loupe mode and thus need to use the 1:1 preview. Do I have this right?
No. 1:1 previews are NEVER regenerated in the Develop module. The only previews that are regenerated as you make edits are the smaller thumbnail previews (remember, each "Preview" is a container in which can be stored 6 or more differently-sized jpegs, the largest of which will be the Standard and 1:1 preview....neither of which are regenerated during editing). When you return to the Library module, and IF the images that you recently edited in Develop are still showing on screen either in the Grid or Filmstrip, then the Standard preview will silently be regenerated, but not the 1:1 preview. The latter is only regenerated by zooming into 1:1 or by using the Build 1:1 Previews option in the Library menu.
 
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Not entirely. Generating 1:1 previews during import is useful if you typically use a zoomed-in view when making the initial culling decisions in the Library module
And for this reason I suggest choosing Embedded and Sidecar in the Import dialog rather than 1:1. This more recent choice makes LR use the preview created by the camera, and is typically faster than generating the 1:1.
 
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And for this reason I suggest choosing Embedded and Sidecar in the Import dialog rather than 1:1. This more recent choice makes LR use the preview created by the camera, and is typically faster than generating the 1:1.
But if I wanted to be able to use Loupe view in my culling process wouldn't it be better to generate the 1:1 previews upon import, since when I went to Loupe view LR would then generate the 1:1 preview on the fly?

Also, if LR uses the camera-generated preview, won't I be looking at the jpg the camera generates rather than what LR shows from the RAW image? Is there a reason to prefer LR's rendering of the RAW image rather than the camera's?
 
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I used to generate the 1:1 previews upon import, but the embedded + sidecar is quicker and lets me get reviewing the pictures.

Yes, you are right that it will be the camera's rendering, but remember that I was responding to Jim's "making the initial culling decisions in the Library module". I don't really need the LR rendering to keep or trash, so embedded + sidecar is fine. Of course, if I do need to adjust an image to do so, for example if it is under- or over- exposed, then I'll do so and generate 1:1 preview at that time.
 
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One other thing to realise about the Embedded Preview is that like all the other Library previews it's obsolete as soon as you move a slider in Develop, so after any edits have been applied and then returning to the Library you will see the updated standard preview. By "obsolete" I mean that you cannot view it again in Lightroom, although of course it's still embedded in the raw file.

Like John, I also use the embedded preview option now (I used to render 1:1 previews on import), frankly it's so much faster, especially when importing larger numbers of images. Of course, not all cameras embed a full-size jpeg, so it's not so ideal for 1:1 culling decisions in those cases.
 
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Of course, not all cameras embed a full-size jpeg, so it's not so ideal for 1:1 culling decisions in those cases.
And having such a camera, I am forced to shoot raw+jpeg. Lightroom then uses the full-size jpeg for the embedded + sidecar workflow.

There's no further need of the jpeg after I've decided which to keep/trash, and I accept they will slightly clutter up my folders. But I'd be using the same disc space if the camera had embedded a full size jpeg.
 
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