Posted by Mark Pelton on January 17, 2012 at 4:48 PM
In Adobe Camera RAW I have the workflow option of changing (during conversion of the raw file) the produced image size from 3782pix X 2592pix (10 MP the native resolution of my D200)up to 6144pix X 4113pix (25.3 MP). Is this equivalent to having shot the image (and no further upsizing in raw conversion)with a 25.3 MP sensor ?
Posted by Basil Greber on January 17, 2012 at 5:35 PM
I agree with Basil. Increasing pixel density in this manner simply means that ACR is adding pixels based upon the ones already present, so you're not gaining anything in terms of image quality; you'll just get a larger file. In fact, up-rezzing can introduce artifacts that reduce image quality and harm fine detail.
Your best bet is to work with your files at their native resolution.
--P.
Posted by Mark Pelton on January 17, 2012 at 6:21 PM
OK, say I am going to make a very large print (maybe 24"X36") so with my native resolution I am definitely going to have to uprez the file in photoshop. Won't I be better off (in terms of a cleaner uprez in size) doing this as the file is converted in ACR, instead of converting at the native resolution and then upsizing in photoshop?
"Won't I be better off (in terms of a cleaner uprez in size) doing this as the file is converted in ACR, instead of converting at the native resolution and then upsizing in photoshop?
I really don't know which will work best, since I print at 360 dpi (or 300 depending upon the printer) print resolution.
from scanned 4x5 film. Maybe Paul D., or one the ACR gurus can answer this for you.
Here's a chart from West Coast Imaging that should give you an idea of the quality you can expect. Again, up-rezzing adds pixels based upon those already present. As far as I know, up=rezzing cannot improve upon visual resolution. i.e. line pairs per milimeter.
A 24x36 print from a 10MP file will have to be printed at about 105 dpi (3782px/36in). For a print of this size from a 6144px X 4113px file, your print resolution goes up to about 170 dpi. Careful PS work and sharpening will be required to get a really good print at either of these print resolutions. The best prints are obtained when print resolution is in the 200+ dpi range.
An application like Genuine Fractals, or equivalent, may be a better choice for up-rezzing than the tools in ACR or Photoshop.
--P
Posted by Jim DeWitt on January 18, 2012 at 2:21 AM
The 4' x 7' black and white photos hanging in Fountainhead Antique Auto Museum were all processed by me. All 75 of them. I have blown up postcard-sized images to 48" x 84". I have another 20 in my queue. The techniques that work best vary from photo to photo. Genuine Fractals is now Perfect Resize. It's pretty good, and has a free trial package, but if the photos have flaws - scratches, dust bits, bleaching or tears - Perfect Resize seems to magnify those flaws more than Photoshop CS5's interpolation. As I say, it depends on the original image. By comparison, Perfect Resize does pretty good with detail, where CS5 makes a muddy mess.
None of those tools are ideal. They all guess at how an interpolated pixel should look. That may or may not have anything to do with what the pixel value should be. Faces, for example, are generally disaster areas. But you can get decent images if you work at it. In my project, it's sometimes hours on a single photo. They may or may not be as good as "thin printing" as Preston suggests. You should probably try both.
Good luck.
Posted by David Bostedo on January 18, 2012 at 8:40 AM
Won't I be better off (in terms of a cleaner uprez in size) doing this as the file is converted in ACR, instead of converting at the native resolution and then upsizing in photoshop?
To answer this a little more directly, no, you're no better of doing it in ACR. The size increase in ACR is not performed on the RAW data directly... it's performed after the RAW processing is applied and the pixels determined. So it's exactly the same as doing it in PS, although your control of which algorithm is used is a bit different.
I'd also suggest just letting the printer driver have a crack at it - that can work well too at times. Or one other thing to try is a lanzcos up-ressing algorithm as found in IrfanView or Qimage.
And I am in agreement with Jim that from what I've seen, sometimes Perfect Resize can be a bit better, but usually you won't be able to tell the difference on your wall between it and Photoshop's usual algorithms.
Posted by Mark Pelton on January 18, 2012 at 6:55 PM
Thanks, Guys. David, I had been led to believe that interpolation during the conversion was better, but had not really thought about the algorithm. Is there a way to select bicubic smoother algorithm for ACR use? Thanks for the info.
I'm preparing some landscape images to be printed at 30x40, which is going to require some up-rezing from my 18 megapixel native image. Just last night I downloaded the trial version of Perfect Resize (half off sale through 1/19) to see how well it worked. I also did some web searches and found there are several people who beleive that you get just as good results in Photoshop or Photoshop Elements. I even found some people who compared the results from Perfect Resize against an up-rezed image created using the Lightroom export module. I did my own experiment processing a landscape through Perfect Resize and Lightroom 3 and found there was not a significant difference in the two! This blew me away. My test image was mostly rocks, trees, leaves, and other detailed subjects with no smooth skies, skin, etc. I also found Perfect Resize to be very slow where Lightroom was very fast because the large image was not produced until the output step.
To be fair, Perfect Resize has many features and controls and may very well produce better resutls when your working with a specific type paper and printer. For me, I think I'm going with the Lightroom output.
Discussion
9 repliesYour best bet is to work with your files at their native resolution.
--P.
Thanks (please forgive the intrusion)
Sandy
I really don't know which will work best, since I print at 360 dpi (or 300 depending upon the printer) print resolution.
from scanned 4x5 film. Maybe Paul D., or one the ACR gurus can answer this for you.
Here's a chart from West Coast Imaging that should give you an idea of the quality you can expect. Again, up-rezzing adds pixels based upon those already present. As far as I know, up=rezzing cannot improve upon visual resolution. i.e. line pairs per milimeter.
A 24x36 print from a 10MP file will have to be printed at about 105 dpi (3782px/36in). For a print of this size from a 6144px X 4113px file, your print resolution goes up to about 170 dpi. Careful PS work and sharpening will be required to get a really good print at either of these print resolutions. The best prints are obtained when print resolution is in the 200+ dpi range.
An application like Genuine Fractals, or equivalent, may be a better choice for up-rezzing than the tools in ACR or Photoshop.
--P
None of those tools are ideal. They all guess at how an interpolated pixel should look. That may or may not have anything to do with what the pixel value should be. Faces, for example, are generally disaster areas. But you can get decent images if you work at it. In my project, it's sometimes hours on a single photo. They may or may not be as good as "thin printing" as Preston suggests. You should probably try both.
Good luck.
To answer this a little more directly, no, you're no better of doing it in ACR. The size increase in ACR is not performed on the RAW data directly... it's performed after the RAW processing is applied and the pixels determined. So it's exactly the same as doing it in PS, although your control of which algorithm is used is a bit different.
I'd also suggest just letting the printer driver have a crack at it - that can work well too at times. Or one other thing to try is a lanzcos up-ressing algorithm as found in IrfanView or Qimage.
And I am in agreement with Jim that from what I've seen, sometimes Perfect Resize can be a bit better, but usually you won't be able to tell the difference on your wall between it and Photoshop's usual algorithms.
To be fair, Perfect Resize has many features and controls and may very well produce better resutls when your working with a specific type paper and printer. For me, I think I'm going with the Lightroom output.