‘up res’ files – bicubic or GF?

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Posted By
frankg
Oct 7, 2005
Views
352
Replies
6
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Closed
any thoughts on whether it’s better to use Bicubic Smoother or Genuine Fractals (PrintPro) to enlarge files from a digital camera ?


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Jim
Oct 7, 2005
"frankg" wrote in message
any thoughts on whether it’s better to use Bicubic Smoother or Genuine Fractals (PrintPro) to enlarge files from a digital camera ?

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6 one, half a dozen the other. That is if you aren’t extrapolating very much, which is what all I need.
Jim
BV
Bart van der Wolf
Oct 7, 2005
"frankg" wrote in message
any thoughts on whether it’s better to use Bicubic Smoother or Genuine Fractals (PrintPro) to enlarge files from a digital camera ?

Depends on how much you resample (which digicam to what output size), and what type of images you shoot.

Bart
F
frankg
Oct 8, 2005
….
any thoughts on whether it’s better to use Bicubic Smoother or Genuine Fractals (PrintPro) to enlarge files from a digital camera ?

Depends on how much you resample (which digicam to what output size), and what type of images you shoot.

I’m talking about approx 150% up

I have since also heard about PhotoZoom Pro.

I understand that they use different "up-rez" techniques but when I look at a side by side comparison of the same file enlarged by the same amount, I cant visually see a superior result. Are there instances where this may be more obvious? What do you look for in an image to decide which program should be used to "up-res" it ?
BV
Bart van der Wolf
Oct 8, 2005
"frankg" wrote in message

any thoughts on whether it’s better to use Bicubic Smoother or Genuine Fractals (PrintPro) to enlarge files from a digital camera ?

Depends on how much you resample (which digicam to what output size), and what type of images you shoot.

I’m talking about approx 150% up

Then it would be hard to see much of a difference with adequate sharpening after interpolation, assuming you are sure about the 150%.

To make sure, as an example let’s take an image from an EOS-350D (3456×2304 pixels, 8MP, physical sensor size = 22.2×14.8mm). Printing such a file at the native inkjet printer resolution (@600 or @720 PPI) on an 8x10in would require 4800×6000 or 5760×7200 pixels so upto 250% for an uncropped image
file. For that amount it will become necessary to have very good interpolation.

If you also consider that such an 8 inch output size results in a magnification of the on-sensor resolution (theoretical maximum = 77.8 lp/mm) of 203.2 / 14.8 = 13.7x, the factual resolution will have dropped to 77.8 / 13.7 = 5.7 lp/mm, which is considered to be on the lower side of the pro quality range at normal viewing distance. 8 lp/mm is considered about as good as photochemical projection print and close to human visual acuity, inkjet printers can do better (11.8 to 14.2 lp/mm).
A poorer interpolator will degrade the quality faster than the better interpolators will.

I have since also heard about PhotoZoom Pro.

Yes that’s one of the better interpolators, although I prefer Qimage for printing because it offers a much better workflow, and at a lower price.

I understand that they use different "up-rez" techniques but when I look at a side by side comparison of the same file enlarged by the same amount, I cant visually see a superior result. Are there instances where this may be more obvious?

First make sure there *is* enough image detail to make a sharp print. Resampling a low resolution image will most likely not make much difference, no matter what method is used.

Also, if you leave part of the resampling up to the printer driver, it becomes a black box without control over resampling method and subsequent sharpening. If the image has lots of critical detail in it,
e.g. nature photography or some kinds of fashion photography, you’ll
need a realistic transition going from in-focus to out-of-focus. If images have large smooth gradients, you’ll need a method that avoids posterization. A lot depends on the quality of the source material.

What do you look for in an image to decide which program should be used to "up-res" it ?

I do all my (automatic) resampling for print with Qimage. It produces good results from most types of images with it’s "Pyramid" method.

Bart
T
Tacit
Oct 8, 2005
In article <95z1f.4848$>,
"frankg" wrote:

any thoughts on whether it’s better to use Bicubic Smoother or Genuine Fractals (PrintPro) to enlarge files from a digital camera ?

Genuine Fractals is the digital equivalent of snake oil, overhyped and advertised in borderline unethical ways by a company which claims it can do things it can’t.

The reality is, there is no way to increase the number of pixels in a raster (pixel-based) image and create detail that does not exist in the original. It’s not even theoretically possible. No program, no technique, and no algorithm can do it.

Photoshop, if used carefully, can give results as good as third-party solutions like Genuine Fractals, but nothing will give great results. The best way to enlarge an image from a digital camera is to buy a digital camera with better resolution.

Sorry…


Art, photography, shareware, polyamory, literature, kink: all at http://www.xeromag.com/franklin.html
F
frankg
Oct 9, 2005
thanks

"Bart van der Wolf" wrote in message
"frankg" wrote in message

any thoughts on whether it’s better to use Bicubic Smoother or Genuine Fractals (PrintPro) to enlarge files from a digital camera ?

Depends on how much you resample (which digicam to what output size), and what type of images you shoot.

I’m talking about approx 150% up

Then it would be hard to see much of a difference with adequate sharpening after interpolation, assuming you are sure about the 150%.
To make sure, as an example let’s take an image from an EOS-350D (3456×2304 pixels, 8MP, physical sensor size = 22.2×14.8mm). Printing such a file at the native inkjet printer resolution (@600 or @720 PPI) on an 8x10in would require 4800×6000 or 5760×7200 pixels so upto 250% for an uncropped image
file. For that amount it will become necessary to have very good interpolation.

If you also consider that such an 8 inch output size results in a magnification of the on-sensor resolution (theoretical maximum = 77.8 lp/mm) of 203.2 / 14.8 = 13.7x, the factual resolution will have dropped to 77.8 / 13.7 = 5.7 lp/mm, which is considered to be on the lower side of the pro quality range at normal viewing distance. 8 lp/mm is considered about as good as photochemical projection print and close to human visual acuity, inkjet printers can do better (11.8 to 14.2 lp/mm). A poorer interpolator will degrade the quality faster than the better interpolators will.

I have since also heard about PhotoZoom Pro.

Yes that’s one of the better interpolators, although I prefer Qimage for printing because it offers a much better workflow, and at a lower price.
I understand that they use different "up-rez" techniques but when I look at a side by side comparison of the same file enlarged by the same amount, I cant visually see a superior result. Are there instances where this may be more obvious?

First make sure there *is* enough image detail to make a sharp print. Resampling a low resolution image will most likely not make much difference, no matter what method is used.

Also, if you leave part of the resampling up to the printer driver, it becomes a black box without control over resampling method and subsequent sharpening. If the image has lots of critical detail in it, e.g. nature photography or some kinds of fashion photography, you’ll need a realistic transition going from in-focus to out-of-focus. If images have large smooth gradients, you’ll need a method that avoids posterization. A lot depends on the quality of the source material.

What do you look for in an image to decide which program should be used to "up-res" it ?

I do all my (automatic) resampling for print with Qimage. It produces good results from most types of images with it’s "Pyramid" method.
Bart

Must-have mockup pack for every graphic designer 🔥🔥🔥

Easy-to-use drag-n-drop Photoshop scene creator with more than 2800 items.

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