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Author Topic: Up-res advice  (Read 3286 times)
FrankG
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« on: March 06, 2013, 07:38:10 PM »
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Busy reading an article Jeff Schewe wrote in 2005 - 'The Art of The Up Res' . Now it's 2013 - I have CS6 & ACR 7.3 so things may have evolved since then.

I also searched for an answer to my question online (& another forum) and am still looking.

I am asking what the best way is to upsample my images. Of course there are many variables that will influence quality but in general is it better to use ACR  or bicubic smoother or look for a plug-in like Blowup or Genuine Fractals, or Photozoom etc or perhaps a combination of of the above?

I am no software engineer and some of the intricacies discussed on threads were beyond my comprehension.

This question arose for me because I have a file that originated on the 5D (the original version - I now have the Mk2) which was only 12MP. The dimensions are 4368 px x 2912 px (or 9.7 x 14.5 inches at 300dpi).

I have been asked for a very large 30 x 40 inch print which is 12000px x 8000px. That's almost 3x !

Of course the quality of the original file, print viewing distance, & subjective opinions about what constitutes 'high quality' means that 'good' is different to different people, and I can't quantify it with numbers except to say it has to satisfy critical pros.

Someone at a lab looked at my layered file (with D&B, healing/spotting/cloning, levels etc.) and asked for the original RAW file which he then graciously upscaled and sent back to me. I am retouching it now and have not yet seen a print but it seems promising.

I don't know how, or with what product, the upscaling was done ? It appears to be a "trade secret" because I asked and he won't divulge the method used.
Personally I don't know of a way other than ACR (up to 25mp), PS (bicubic smoother), or a plug-in.

I tried to replicate what he did but cant quite get the same 'smoothness' combined with 'sharpness' by first using ACR to the max (25MB) and then in PS bicubic smoother the rest of the way up.
Of course there may be variables such as the amount of sharpening applied in ACR (or none?) & other settings.
It's been like shooting in the dark...trial & error etc

Any light you can throw on the best way to up-sample (just a short version :-) is appreciated .

Thanks,
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Jim Kasson
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« Reply #1 on: March 06, 2013, 09:00:27 PM »
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I am asking what the best way is to upsample my images.

Frank,

An upsampling program takes the image with its original sampling, builds a model of what the original image might have looked like, and samples that image at a finer pitch. The trick is building the right model. It's even trickier, since "right" means "whatever satisfies the user". There is no silver bullet. If we want to have an upsampled image that looks sharp, we're asking the upsampling program to make up data. What looks good to you on one image may look bad to someone else. What looks good to you on one image may look bad to you on another.

The algorithms built into Photoshop are of the "first do no harm" variety. Used for upsampling  (downsampling is a different kettle of fish), they will rarely cause artifacts, but may give up some apparent sharpness.

Other algorithms -- some secret -- may exhibit more apparent sharpness, but their smoothness may not satisfy you.

Here's a comparison of the standard algorithms with a proprietary one at close to your three to one ratio: http://blog.kasson.com/?p=1913

There are several resampling programs that let you choose from many non-proprietary and some proprietary algorithms. QImage is one. There are others. I suugest you try one or two and see what you like.

If you want to save money and use what Photoshop ships with, take a look at this:
http://www.digitalphotopro.com/technique/software-technique/the-art-of-the-up-res.html?start=1

Of course the quality of the original file, print viewing distance, & subjective opinions about what constitutes 'high quality' means that 'good' is different to different people, and I can't quantify it with numbers except to say it has to satisfy critical pros.

I think the person it has to satisfy is you.

Jim
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FrankG
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« Reply #2 on: March 06, 2013, 09:25:55 PM »
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thanks for that Jim.
I was reading the Jeff Schewe article that you linked  but thought it may be old and that new products or methods may in the interim have superceded it ?
Great to see the visual comparisons - Perfect Resize' certainly wins that contest.
It would be so interesting to see the same example with BlowUp and Genuine Fractals and others included.

One question i have is notwithstanding the excellence of a plug-in like Perfect Resize, is it better to upsample as far as camera raw (ACR) will allow first, and then apply further enlargement with PS or one of these apps?
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Schewe
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« Reply #3 on: March 06, 2013, 09:42:54 PM »
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I also searched for an answer to my question online (& another forum) and am still looking.

You didn't find this thread?
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Jim Kasson
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« Reply #4 on: March 06, 2013, 09:46:01 PM »
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It would be so interesting to see the same example with BlowUp and Genuine Fractals and others included.

Perfect Resize is the new name for Genuine Fractals.

One question i have is notwithstanding the excellence of a plug-in like Perfect Resize, is it better to upsample as far as camera raw (ACR) will allow first, and then apply further enlargement with PS or one of these apps?

I can't help you there. I've never looked at upsizing in ACR. A demosaicing program like ACR builds a model of a continuous image like that done by an upsampling program, and, if it can use that model for upsizing, there's a potential advantage there. My guess is that it would be better to go all the way to the resolution you need in one step, but that's just a guess.

Jim
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Schewe
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« Reply #5 on: March 06, 2013, 10:21:56 PM »
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One question i have is notwithstanding the excellence of a plug-in like Perfect Resize, is it better to upsample as far as camera raw (ACR) will allow first, and then apply further enlargement with PS or one of these apps?

While ACR will limit the size of the upsampling in the Workflow Option dlog, there is another way to upsample in ACR by using the Custom Crop dlog. The trick is to select the Custom Crop, set the unit to Pixels, use a calculator to multiply the original pixel dimensions by the amount of size increase and enter those numbers in the custom crop entry. So, if the original pixel size was 3888 x 2592, you would multiply each number by the same factor. In the test case I just did, I multiplied by 3 to get 11664 x 7776 pixels. The end result looked pretty good (although could use a touch of sharpening in Photoshop). BTW, there upwards limit to this; 65,000 x 65,000 or 512MP. The same upsample size limit is in LR in Export.
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sniper
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« Reply #6 on: March 07, 2013, 04:25:30 AM »
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I did a test about a year back comparing photoshops bicubic smoother v perfect resize, I went up about 300% in both, as far as I could see perfect resize was ever so slightly better, but not enough to really make a difference in a real world print at "normal" viwewing distance.
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hjulenissen
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« Reply #7 on: March 07, 2013, 04:51:19 AM »
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I find this thread interesting, even though it is primarily about downsampling:
http://www.imagemagick.org/discourse-server/viewtopic.php?f=1&t=20992&start=240
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Jim Kasson
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« Reply #8 on: March 07, 2013, 08:43:33 AM »
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Jeff,

You got me thinking about the (at least theoretical) advantages of resizing to final size directly from the mosaiced data, and it's pretty intriguing. It's not a very practical workflow to go back through ACR and lose all your edits every time you change print size, but if it were done in Lightroom, the user wouldn't even notice. Well, the user wouldn't notice in the Print module, but what would zooming to 100% mean when you didn't know how many pixels wide the image was going to turn out to be? Made my head hurt.

There might be a pony in there...

But maybe LR resizing is good enough the way it is.

Jim
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jrsforums
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« Reply #9 on: March 07, 2013, 09:41:18 AM »
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While ACR will limit the size of the upsampling in the Workflow Option dlog, there is another way to upsample in ACR by using the Custom Crop dlog. The trick is to select the Custom Crop, set the unit to Pixels, use a calculator to multiply the original pixel dimensions by the amount of size increase and enter those numbers in the custom crop entry. So, if the original pixel size was 3888 x 2592, you would multiply each number by the same factor. In the test case I just did, I multiplied by 3 to get 11664 x 7776 pixels. The end result looked pretty good (although could use a touch of sharpening in Photoshop). BTW, there upwards limit to this; 65,000 x 65,000 or 512MP. The same upsample size limit is in LR in Export.

Jeff, what algorithm is used in the ACR upsampling and/or Custom Crop dialog?

John
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John
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« Reply #10 on: March 07, 2013, 01:40:35 PM »
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Jeff, what algorithm is used in the ACR upsampling and/or Custom Crop dialog?

It's an adaptive interpolation between Bicubic and Bicubic Smoother for upsample and Bicubic and Bicubic Sharper for downsample–which is something Photoshop can't do. The way I understand it, if you are upsampling a LOT, then it's mostly Bicubic Smoother. But the advantage is that ACR/LR automatically interpolates your capture sharpening and noise reduction up as well.
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FrankG
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« Reply #11 on: March 08, 2013, 02:33:00 PM »
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@ Jeff- jeez you sure know your stuff. After going round and round with this thing trying every which way,
I have been at this thing like a bulldog and comparing all my results to the 'unknown upsample' version.
As you indicated, I just did the entire upscale with the crop tool in ACR, and followed this with USM at 275, 1, 0 and I'd say, for all intents and purposes, I'm there.
This is pretty darn close to the result I was looking to match
Now there may be tweaks in ACR that I could/should do (I don't know enough about how to set the noise and sharpening settings there).
Also I'm not saying that there is no further sharpening required for output (variable depending on media etc).
But this is a great upsample IMHO & I'm excited

Any ideas on fine-tuning the ACR settings or capture sharpening on the tif please share.
« Last Edit: March 08, 2013, 07:34:24 PM by FrankG » Logged
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