Previews for JPEG files? Why?

[funkahdafi]

Hi there,

I am new to Lightroom, coming from Aperture. While playing with it, I also imported a couple of hundred older JPEG files of photos I took before I started to shoot in RAW. To my big surprise, Lightroom started to build previews for these JPEGs.

Is this normal? Aren't previews just made for RAW? I mean, what't the point in creating a JPEG preview of a JPEG file?

Maybe you can give me some insight on the concept of previews in Lightroom. I seem to misunderstand it.

What if I zoom into one of those files, will Lightroom only display the generated preview or will it display the original JPEG?

Thanks

 

[DonRicklin]

Everything done in Lightroom even to JPEGs is non-destructive Database stored. They don't get turned to real pixel changes until export. So the only way you will see the changes in LR is with previews!

Don

 

[funkahdafi]

Everything done in Lightroom even to JPEGs is non-destructive Database stored. They don't get turned to real pixel changes until export. So the only way you will see the changes in LR is with previews!

Don

yes, but that was not my question really. Why does Lightroom create a preview for each JPEG on import? Wouldn't it be much fuster to keep the JPEGs as they are and only create a new "version" as soon as you start editing it?

So if LR creates a preview for every file, what is it that I am looking at when viewing the pictures? Am I looking at the preview or the real thing?

Am I mixing the concepts of versions and previews?

Sorry, but I don't get it. I don't see why I need a preview for a JPEG unless I want to edit it (and then I would still call it a version instead of a preview).

Is there some place or document where I can read up about the basic concepts? The provided online help within LR goes into great detail on how to do stuff, but it doesn't really explain why there is a preview at all.

 

[Kiwigeoff]

yes, but that was not my question really. Why does Lightroom create a preview for each JPEG on import? Wouldn't it be much fuster to keep the JPEGs as they are and only create a new "version" as soon as you start editing it?

So if LR creates a preview for every file, what is it that I am looking at when viewing the pictures? Am I looking at the preview or the real thing?

Am I mixing the concepts of versions and previews?

Sorry, but I don't get it. I don't see why I need a preview for a JPEG unless I want to edit it (and then I would still call it a version instead of a preview).

Is there some place or document where I can read up about the basic concepts? The provided online help within LR goes into great detail on how to do stuff, but it doesn't really explain why there is a preview at all.

Welcome, please take a mac moment to fill in your signature.
I guess it is so that all files go through the same processes. As Don said everything done is nondestructive so LR builds previews for all files to display what has been done. This information may not be sent to the files, depending on your settings and personal preferences.
For example if you choose to have autowrite to xmp turned off then the only time the file is updated is if you cmd-s or export the file. As the develop information would only be held in the database, if you haven't saved it to file, the file and the LR database information would be different, hence LR has it's own previews to show the database settings, not the file settings - although they may be the same.
With raw of course a preview is necessary as the raw info isn't an image file.

Hope that helps!!:lol::lol::lol:

 

[DonRicklin]

You can set the import previews to 'minimal'

Don

 

[nguzman]

Your questions are answered in George Jardine's tutorial in Adobe Photoshop Lightroom Podcast #45. You can get these podcasts free from iTunes. This particular podcast answers questions like, "Where are my pictures?" and "What am I looking at?"

 

[funkahdafi]

all right. thanks. allow me one more question please: say my jpegs are of very high quality. on import, I choose to render minimal previews. After rendering them and looking at the photos, will I look at the less quality preview or the original jpeg with the higher resolution?

 

[Victoria Bampton]

When you look at a file in Library module, it will render a standard preview for it if you haven't done so already (so it's quicker to render standard previews on import), and you will be looking at that preview (which is just a smaller copy of your original file until you zoom in, at which point it renders a full size copy of your original file).

If you go into Develop, it initially shows you the preview and then shows you the original file, as it assumes you want a much more accurate view at that point.

If it were to read the original file every time you just wanted to flick through your photos, LR would be slower, as they would be bigger files to load.

 

[funkahdafi]

how about slideshow mode? low quality previews or the real thing?

 

[Victoria Bampton]

how about slideshow mode? low quality previews or the real thing?

Previews - which is just a smaller version of the real thing, remember.

Only Develop reads the original file - oh, and Print when you have Draft Mode turned off.

 

[Denis Pagé]

So if LR creates a preview for every file, what is it that I am looking at when viewing the pictures? Am I looking at the preview or the real thing?

Am I mixing the concepts of versions and previews?

Sorry, but I don't get it. I don't see why I need a preview for a JPEG unless I want to edit it (and then I would still call it a version instead of a preview).

If you do not have Auto write to XMP turned on, there is also another advantage to have previews of your images in the database rather than the originals themselves.

For example, you can have you originals on an external drive and Lightroom running on a Laptop. Then, you can unplug the external drive, take the Laptop with you on the Bus, Train or else and start to keyword you photos without the originals. Other things can be done also...