Author Topic: Generate high-quality previews possible?  (Read 4132 times)

Offline nharnik

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Generate high-quality previews possible?
« on: March 26, 2008, 09:21:30 AM »
When a contact sheet loads, it first shows low quality thumbnails. Then (as I had set in my preferences) high quality previews are generated for all the thumbnails in the folder.

When I open an image in the preview window, at first a lower resolution image opens, then a higher resolution image is generated. If I zoom into an image, an even higher resolution image is generated.
(I assume all these images are stored in the cache)

Is there a way I can make PM automatically generate the high-resolution images for the preview window for all images in the folder, even the ones I had not viewed yet?  (as in mimic the high-resolution generation process done in the contact sheet view?)

It would be a huge benefit to me to instantly see a high-res preview

thanks,
nati

Offline Kirk Baker

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Re: Generate high-quality previews possible?
« Reply #1 on: March 26, 2008, 01:16:32 PM »
nati,

When a contact sheet loads, it first shows low quality thumbnails. Then (as I had set in my preferences) high quality previews are generated for all the thumbnails in the folder.

When I open an image in the preview window, at first a lower resolution image opens, then a higher resolution image is generated. If I zoom into an image, an even higher resolution image is generated.
(I assume all these images are stored in the cache)

Is there a way I can make PM automatically generate the high-resolution images for the preview window for all images in the folder, even the ones I had not viewed yet?  (as in mimic the high-resolution generation process done in the contact sheet view?)

It would be a huge benefit to me to instantly see a high-res preview

There is no way to force PM to automatically generate high-resolution previews.  Doing so could have several issues.  The disk cache could fill up before all previews are generated.  Making the cache generate all images in the background would reduce responsiveness throughout the application.  There are probably other issues but I haven't thought the idea completely through yet.

-Kirk


Offline nharnik

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Re: Generate high-quality previews possible?
« Reply #2 on: March 26, 2008, 09:10:15 PM »
Kirk,
Thanks for explaining. I am just beginning to appreciate how complex cach managment is.
I was just looking to avoid the lower resolution previews, which sometimes during a "fast and furious" edit I mistake them for out-of-focus images.
So while your answer seems to indicate there is no way to go directly to high-res previews, I may have found a semi-solution. 
In cach preferences I have upped my disk cach size to 2048 MB, with 1000 MB reserved on the disk cach volume and memory cach size is 1024 MB.
There is a marked improvement in program responsiveness. I also find that the high-res images that are now generated in preview mode persist when I quickly scroll backwards and forwards. (with my earlier and smaller cach they were generated over and over again.)   
So if a big cach is helpful, how big would I have to configure the disk cach so it retains all the high res images generated from a 1 gig cf card full of fine quality jpegs? Is there a limit to the size of the cach? (other than the limitation of the size of the hard drive?)
o, yes, and i am on a windows xp machine with 2 gig memory and a large hard drive.
thanks, nati
 

Offline Kirk Baker

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Re: Generate high-quality previews possible?
« Reply #3 on: March 26, 2008, 11:10:22 PM »
Nati,

Thanks for explaining. I am just beginning to appreciate how complex cach managment is.
I was just looking to avoid the lower resolution previews, which sometimes during a "fast and furious" edit I mistake them for out-of-focus images.
So while your answer seems to indicate there is no way to go directly to high-res previews, I may have found a semi-solution. 
In cach preferences I have upped my disk cach size to 2048 MB, with 1000 MB reserved on the disk cach volume and memory cach size is 1024 MB.
There is a marked improvement in program responsiveness. I also find that the high-res images that are now generated in preview mode persist when I quickly scroll backwards and forwards. (with my earlier and smaller cach they were generated over and over again.)   
So if a big cach is helpful, how big would I have to configure the disk cach so it retains all the high res images generated from a 1 gig cf card full of fine quality jpegs? Is there a limit to the size of the cach? (other than the limitation of the size of the hard drive?)
o, yes, and i am on a windows xp machine with 2 gig memory and a large hard drive.

The setting that you changed that gave you the most improvement was the change to the Memory Cache.  But you may find that you have set it too high at 1024 MB since you only have 2048 MB of RAM on your system.  This could cause swapping if you were to use another memory-hungry application like Photoshop.  I'd suggest setting the Memory Cache to something lower like 600 MB or even 512 MB.

As for retaining high-res previews of fine quality JPEGs: if you're talking about 100% previews, the cache is not used at all for 100% previews.  The image itself is loaded when needed.  Only the scaled-to-fit images are cached to disk.

Another setting you can change that will give you about a 25% speed boost is to turn off color management while previewing.

HTH,

-Kirk


Offline nharnik

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Re: Generate high-quality previews possible?
« Reply #4 on: March 27, 2008, 06:43:29 AM »
Kirk,
It is the scaled-to-fit images that I wanted cached.
Thanks for your help
n

Offline Kirk Baker

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Re: Generate high-quality previews possible?
« Reply #5 on: March 27, 2008, 07:12:15 AM »
nati,

It is the scaled-to-fit images that I wanted cached.

This would be hard to accomplish because the Preview window can be very dynamic.  For instance, you can view two images at once, or one at a time.  You can change the width of the control panel on the right side or you can hide it altogether.  You can change to full-screen mode, or view the thumbnails.

Each of these cases would change the size of the image that is scaled-to-fit.  If the images were pre-generated and you changed the display size with one of the above methods, all of the pre-generated scaled-to-fit images would be invalid until you went back to the layout used when pre-generating the previews...

-Kirk