Aperture 1.5: Preview Management
2006-10-02
Quick -- which of these two images has a preview?
Managing previews in Aperture 1.5 is a little tricky. First, there is no "preview" badge that tells you whether an image has a preview already made. Secondly, the controls you need to use to manage these things you cannot see are scattered and confusing.
The easiest way I have found to check if a preview exists is to try to drag the images to the desktop. If there is no preview in the selection they will all spring back to the browser. On the left below, neither image has a preview. On the right, at least one does:
The little red 2 shows how many are being dragged, not how may will actually drop. It's the green plus you have to look for. The contextual menu for these images doesn't give a clue either. For images with and without previews, both of the preview actions Update and Delete are present:
So no clues there. And there is nothing in the metadata to help either. And there is no way to filter based on preview status, size, or quality. Maddening really. I believe that the thinking (evidenced by the default for all images to have previews generated) is that you should not care -- everything has previews and they are always available. But I don't believe that most people really want this because off the extra burden of the files and the processing.
When you drag an image with a preview to the desktop it will always use the master file name. It does this if you drag three versions of one file too, so they all end up with the master name and _2, _3 etc. appended. So if you have given your versions sensible names and expect them to still be there, you will not be happy with this behavior.
The second problem, actually controlling previews, is thornier. Since you can't see what is going on, you are operating blind. However it is possible to maintain order as long as you understand your actions and have some sort of philosophy for your personal use of previews. So I will attempt to make things clearer.
Every thumbnail, and hence every version of every master can have one preview. When the preview is created, the current settings in the prefs window are used:
If you don't limit the size of the preview it will be as big as the image. So a 4000x3000 pixel TIFF will result in a 4000x3000 pixel JPG. If you do limit the size, it will be scaled to fit inside a square of the size given in the pop-up. The size with the asterisk by it is the size of your screen, so is a good choice. The preview quality sets the JPEG compression and the file size varies greatly as it is moved. Anything from 7 up seems to be good. All of my images are JPGs, so previews with unlimited size don't make sense for me (they will just be lower-quality copies) unless I need much lower file sizes by setting the quality way down.
If you change the preview settings, nothing happens to your existing previews. And because you cannot filter on preview status, there is no way for you to update all the images with previews to the new settings fully automatically.
Deleting previews is easy and simple. Control click on the thumbnail selection, project or entire library and select Delete Previews. It always does the same thing: deletes your previews. And they are gone completely -- no copies in the trash.
What you cannot do is delete previews for an album, at least by control-clicking on the album. You can select the album, then select all the images, and then delete the previews.
The next simplest thing to do is to generate a preview. Generate means "delete the existing preview if there is one and build a new one using the current settings in the prefs window". You access Generate by option-control clicking on an image selection, project, or library:
Generate will silently fail if the original image is not available; if it is off-line for instance. It won't delete the old preview and it won't generate a new preview, but it won't tell you that is what happened either.
The logic for Update is as follows: "If a preview is already present, do nothing. Otherwise create a preview using the settings from the prefs window". So update really means make sure that all of these images have a preview. You can only make sure that it is a preview of a certain size and quality, however, by using Generate. My advice on the preview settings is to figure out what you need and then never change it.
Each project has a setting to maintain previews or not. It is in the action menu (cog) on the upper right of the project pane. Select a project and turn maintenance on or off:
With maintenance off, all preview generation is manual. You have to delete, update, generate, all by hand. If you turn maintenance on, it will do a one-time Update for all images in the project (not a generate!) so ensuring that all images have a preview. Once on, maintenance will make previews for all new images and will generate a new preview for all image edits, making sure that the previews stay in sync with the thumbnails. However if you create a new version of an image, it will not get a preview. I think that is a bug. It is certainly inconsistent behavior, and one that adds to the confusion. Further, if you delete that new version, the preview does not get deleted from the library. One way to quickly force a new version preview from the keyboard is to rotate the image left then right using the [ and ] keys.
You can also turn on preview maintenance for the whole library. This does the equivalent of turning on maintenance for every project in the library.
When you turn off preview maintenance for a project preview control goes back to being fully manual. The existing previews stay as they are. Turning off preview maintenance for the whole library simply turns off preview maintenance for every project.
And finally, the setting in the prefs window New Projects Automatically Generate Previews determines whether new projects are created with maintenance turned on or off.
Once you have mastered this behavior you should be able to keep previews from taking over your library and your life. For a workflow-oriented application, they are implemented a little oddly. But I expect Apple to tweak this behavior as they learn how people want to use them. For my own part I will be turning automatic creation of previews off and generating screen-sized images for only the last few months' projects so that I have something to use in other applications and put on my desktop as wallpaper.
Managing previews in Aperture 1.5 is a little tricky. First, there is no "preview" badge that tells you whether an image has a preview already made. Secondly, the controls you need to use to manage these things you cannot see are scattered and confusing.
A Game Of Spot The Preview
The easiest way I have found to check if a preview exists is to try to drag the images to the desktop. If there is no preview in the selection they will all spring back to the browser. On the left below, neither image has a preview. On the right, at least one does:
The little red 2 shows how many are being dragged, not how may will actually drop. It's the green plus you have to look for. The contextual menu for these images doesn't give a clue either. For images with and without previews, both of the preview actions Update and Delete are present:
So no clues there. And there is nothing in the metadata to help either. And there is no way to filter based on preview status, size, or quality. Maddening really. I believe that the thinking (evidenced by the default for all images to have previews generated) is that you should not care -- everything has previews and they are always available. But I don't believe that most people really want this because off the extra burden of the files and the processing.
When you drag an image with a preview to the desktop it will always use the master file name. It does this if you drag three versions of one file too, so they all end up with the master name and _2, _3 etc. appended. So if you have given your versions sensible names and expect them to still be there, you will not be happy with this behavior.
The second problem, actually controlling previews, is thornier. Since you can't see what is going on, you are operating blind. However it is possible to maintain order as long as you understand your actions and have some sort of philosophy for your personal use of previews. So I will attempt to make things clearer.
Preview Size and Quality
Every thumbnail, and hence every version of every master can have one preview. When the preview is created, the current settings in the prefs window are used:
If you don't limit the size of the preview it will be as big as the image. So a 4000x3000 pixel TIFF will result in a 4000x3000 pixel JPG. If you do limit the size, it will be scaled to fit inside a square of the size given in the pop-up. The size with the asterisk by it is the size of your screen, so is a good choice. The preview quality sets the JPEG compression and the file size varies greatly as it is moved. Anything from 7 up seems to be good. All of my images are JPGs, so previews with unlimited size don't make sense for me (they will just be lower-quality copies) unless I need much lower file sizes by setting the quality way down.
If you change the preview settings, nothing happens to your existing previews. And because you cannot filter on preview status, there is no way for you to update all the images with previews to the new settings fully automatically.
Deleting Previews
Deleting previews is easy and simple. Control click on the thumbnail selection, project or entire library and select Delete Previews. It always does the same thing: deletes your previews. And they are gone completely -- no copies in the trash.
What you cannot do is delete previews for an album, at least by control-clicking on the album. You can select the album, then select all the images, and then delete the previews.
Generating Previews
The next simplest thing to do is to generate a preview. Generate means "delete the existing preview if there is one and build a new one using the current settings in the prefs window". You access Generate by option-control clicking on an image selection, project, or library:
Generate will silently fail if the original image is not available; if it is off-line for instance. It won't delete the old preview and it won't generate a new preview, but it won't tell you that is what happened either.
Updating Previews
The logic for Update is as follows: "If a preview is already present, do nothing. Otherwise create a preview using the settings from the prefs window". So update really means make sure that all of these images have a preview. You can only make sure that it is a preview of a certain size and quality, however, by using Generate. My advice on the preview settings is to figure out what you need and then never change it.
Maintaining Previews
Each project has a setting to maintain previews or not. It is in the action menu (cog) on the upper right of the project pane. Select a project and turn maintenance on or off:
With maintenance off, all preview generation is manual. You have to delete, update, generate, all by hand. If you turn maintenance on, it will do a one-time Update for all images in the project (not a generate!) so ensuring that all images have a preview. Once on, maintenance will make previews for all new images and will generate a new preview for all image edits, making sure that the previews stay in sync with the thumbnails. However if you create a new version of an image, it will not get a preview. I think that is a bug. It is certainly inconsistent behavior, and one that adds to the confusion. Further, if you delete that new version, the preview does not get deleted from the library. One way to quickly force a new version preview from the keyboard is to rotate the image left then right using the [ and ] keys.
You can also turn on preview maintenance for the whole library. This does the equivalent of turning on maintenance for every project in the library.
When you turn off preview maintenance for a project preview control goes back to being fully manual. The existing previews stay as they are. Turning off preview maintenance for the whole library simply turns off preview maintenance for every project.
And finally, the setting in the prefs window New Projects Automatically Generate Previews determines whether new projects are created with maintenance turned on or off.
Once you have mastered this behavior you should be able to keep previews from taking over your library and your life. For a workflow-oriented application, they are implemented a little oddly. But I expect Apple to tweak this behavior as they learn how people want to use them. For my own part I will be turning automatic creation of previews off and generating screen-sized images for only the last few months' projects so that I have something to use in other applications and put on my desktop as wallpaper.
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