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Author Topic: Lightroom up-rez?  (Read 5920 times)

stever

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Lightroom up-rez?
« on: September 03, 2007, 04:37:12 pm »

Trying to decide whether to use Lightroom for up-rezing (moderately) in the Print module or continue to do it in PS

Can't find any info on how Lightroom re-sizes
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oldcsar

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Lightroom up-rez?
« Reply #1 on: September 03, 2007, 05:33:18 pm »

Why don't you uprez in both and see if there are any visible differences in detail retention between LR and PS? I'm not sure if there are any differences between their interpolations, I'm guessing LR uses Bicubic Smoother for upsizing and bicubic sharper for downsizing (likely identical to PS counterparts). Since I haven't heard anything special about LR resizing, I'm thinking this is the case, although I could be wrong. There are programs such as Genuine Fractals and Photozoom Pro 2 which offer alternative interpolation methods to Adobe's bicubic interpolations, with arguably better, but different results.
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stever

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Lightroom up-rez?
« Reply #2 on: September 03, 2007, 11:31:54 pm »

because i'm lazy -- if someone knows the answer or has done the test it will save me a couple hours
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digitaldog

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Lightroom up-rez?
« Reply #3 on: September 04, 2007, 09:41:11 am »

Haven't tried LR and the tests I did in CR where a solid version back so YMMV. However, when I compared the two, the differences in CR and LR where almost identical. I had to actually use calculations to see the differences at a pixel level. Thomas Knoll once reported the math IS different which makes sense. One is linear gamma encoded for one. My take is this. IF I know I need to rez up from the get-go, I'll do it in the converter. If not, I don't and will, if necessary do it later. But really, do a test. I'd use Bicubic smoother in PS. Its always more valuable to test the waters yourself and see if there's anything YOU think is useful in one technique versus the other.
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CatOne

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Lightroom up-rez?
« Reply #4 on: September 04, 2007, 12:54:24 pm »

So does LR use the same approach for upressing as does ACR?  I know I'd heard recommendations to upres in ACR before going to Photoshop, given it did a very good job.  Not sure whether LR does the same thing or not -- it would seem to make sense.
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digitaldog

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Lightroom up-rez?
« Reply #5 on: September 04, 2007, 12:57:21 pm »

Quote
So does LR use the same approach for upressing as does ACR?  I know I'd heard recommendations to upres in ACR before going to Photoshop, given it did a very good job.  Not sure whether LR does the same thing or not -- it would seem to make sense.
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Unless something has changed recently, it should be using the same processing as CR.
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Giedo

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Lightroom up-rez?
« Reply #6 on: September 04, 2007, 04:15:52 pm »

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Unless something has changed recently, it should be using the same processing as CR.
[a href=\"index.php?act=findpost&pid=137253\"][{POST_SNAPBACK}][/a]
According to Mikkel Aaland in his book Lightroom Adventure (which I do recommend!) LR interpolates using a Lanczos kernel method. But the real difference with Photoshop would be that it resamples in linear space, which unlike Photoshop avoids darkening around edges. Especially in upsampling LR should do a better job than Photoshop (again according to Mikkel Aaland)

regards, Giedo
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Giedo

stever

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Lightroom up-rez?
« Reply #7 on: September 04, 2007, 04:51:25 pm »

thanks, i've got the book but missed that part - will re-read

and i will do a test, although i'm now more concerned with some of the sharpening differences between 1.0 & ACR 4.0 vs 1.1 and 4.1  -- probably need to test this first
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Brian Patterson

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Lightroom up-rez?
« Reply #8 on: September 11, 2007, 08:05:02 pm »

I agree with digitaldog - I upsize my order in the PS CS converter. But, I appreciate the comments on LR's methodology. Wish it was available on Import, don't you?

Mule
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Adam L

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Lightroom up-rez?
« Reply #9 on: September 13, 2007, 12:10:39 pm »

Jeff mentions in the C2P video that Lightroom does a better uprez than CS3.
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