Which of the following enlargement strategies gives a better picture
enlarging an image 400% and printing at 360 dpi
or
enlarging an image 300% and printing at 270dpi
schewe, why even bother to make such a useless reply.. ???..if you cannot say anything positive, what do you gain? I am sure you'll probably have some equally irrelevant comment to this post.
Which of the following enlargement strategies gives a better picture
enlarging an image 400% and printing at 360 dpi
or
enlarging an image 300% and printing at 270dpi
in both cases you will end up with the same size picture. Say for example
you have an image that is 900 pixels by 900 pixels
...upsampling from that few pixels to make a print will never be good ...
Could you define 'good', and would that apply to any subject matter?
Starting from 900 x 900 pixels and trying to get anything that will be what I would call an acceptable print at 10" x 10" would fall into the category of not "good". Do you disagree?
I know if you have enough native resolution such as from a 1DsMIII, that very large enlargements can be "good". But that's starting from a 21MP file with 5616 x 3744 pixels. That's a far cry from 900 x 900 pixels. Upsampling from a higher MP size will always be better...
900 pixels enlarged to 10 inch at 360 PPI is 4x enlarged or effectively 90 PPI, 5616 pixels enlarged to 3 metres at 360 PPI is 7.57x enlarged or effectively 47-48 PPI. I don't see how the former could be worse than the latter, and the latter can look darned 'good'.
I just did a test...going from 900 x 900 to 10" at 360 prints out like crap, lots of ringing and artifacts from the upsample (bicub smoother in PS)....taking an image that is 5616 to 3 meters will also look like crap unless the viewing distance is from a lot further away than a 10" print.
Yes, you can massage it and make a larger native file size look better, but it'll never look as good with a close viewing distance as a higher rez original.
But trying to get a good print at 10" from 900 x 900 starting pixels? No, not unless your acceptance is a lot lower than mine...maybe I'll adopt yours.
The issue was if the print benefits from upsampling to 360 or not, and it does.
I was hoping to read something from the wizard who did the code for photokit but was saddened to discover his passing in 2005.
Actually, it was 2006 when Bruce passed away (http://brucefraserlegacy.com/)....
Best thing to do is test this on your own printer because YRMV...
Sry, I was still in a fog about M. Skurski who had complications and was thinking about him.
thank you for your lively debate. my research shows that greater enlargement and subsequent greater reduction results in softening of boundaries. so an image scaled up 10 fold with bicubic resampling and then resized to 360 dpi from 72 shows softer edges than an image scaled up 7.5 fold and resized to 270 dpi.
Intuitively that also makes sense. But this is only based on what I see on a monitor. When the images are sprayed onto inkjet paper, I cant really see a difference. I think this may be because the epson printer is resampling the 270 dpi image to 360 dpi and thereby softening the edges. or maybe my old eyes just cannot see.
whether or not an image looks like crap from this kind of extreme rescaling and resizing is not the question. i am trying to determine which rescaling algorithm would produce the least crappy image when you need to upsize your image. And rather than split hairs over subtle differences, I am using an extreme example so I can magnify the effects to come to a clear conclusion.
Since my original post, I have also been reading about others' experience with epson printers. It seems the most critical variable is to maintain the dpi of the output image as a factor of 360.
This eliminates the printer from the rescaling/resizing loop and removes another cycle of image degradation. So the subtle difference I was trying to measure in my initial post, is actually overshadowed by something I never took into account-the printer nozzle density which is fixed at a specific dpi. This renders the initial question moot .
Of course there is no substitute for real pixels, but I'm looking forward to hearing what the findings are ..., does upsampling (sometimes as a last resort) produce crap or what?
Well, I looked at the images (didn't print them mind you) and they are definitely on the crap side of the scale.
The Photozoom looked a tad better but I think S-Spline has a component of sharpening built in, doesn't it?
Here are a couple of examples of what to really expect from upsampling. ... Of course there is no substitute for real pixels, but I'm looking forward to hearing what the findings are ..., does upsampling (sometimes as a last resort) produce crap or what?
According to JIDM, going from the original crop to 400% enlargement the Photozoom Pro version reduces sharpness by a factor of 0.6, where as the BiCubic Smoother version by a factor of 0.125.
Although I don't know if your metric scales linearly (or another correlation) with resolution or with perception,
Here is an interesting thing. I overlaid the FFTs of the 100% crop over the respective 400% enlargements of Photozoom Pro and BiCubic Smoother. Photozoom Pro is shown below. Interestingly, the common portions of the 100% crop and 400% Photozoom Pro enlargement are quite identical, and the spikes in the 100% crop seem to continue in the extended space of the 400% Photozoom Pro.
Indeed, it shows that signal is added at higher spatial frequencies, not just more blurry pixels to fill the gaps.
A thing that I have noticed is that it appears Photozoom Pro is "thining" out the edges by defining sharper transitions.
Because your question indicates a severe lack of understanding and little or no effort on your part? Maybe that's why I answered the way I did. Do some research on your own and get back to us.
The Right Resolution (http://www.digitalphotopro.com/technique/workflow/the-right-resolution.html)
And The Art Of The Up-Res (http://www.digitalphotopro.com/technique/software-technique/the-art-of-the-up-res.html)
Read those and get back to us...
Then I've made 2 examples of 400% enlargements, in line with what the OP gave as a theoretical example (they should print as 5 inch square at 360 PPI). Here (http://bvdwolf.home.xs4all.nl/temp/7640_Crop1_400pct_BiCubSmth.jpg) is one with Photoshop Bicubic Smoother, a quality which according to Jeff "prints out like crap, lots of ringing and artifacts from the upsample". And here (http://bvdwolf.home.xs4all.nl/temp/7640_Crop1_400pct_SSmax.jpg) is one example of a 400% upsampling with Photozoom Pro (S-Spline Max method).The photoshop one obviously is poor, also with what appears to be blocking artifacts?
The photoshop one obviously is poor, also with what appears to be blocking artifacts?
Photozoom pro appear very sharp, but has a "water-colory" quality that I dislike. I actually prefer a more smeared, "linear filtering-like" look.