Major uprez question

[bvstaples]

I've worked in print production for many years, and Genuine Fractals has always served me well. It was originally designed to make billboard sized images from 35mm slides. Of course the resolution needed on a billboard is not that high, but still this is an excellent program for doing what you need–especially if all you need to go from is 16x24 to 20x30, where the percentage increase is small.

Brian

[Tyler Boley]

download the demos of the various plugins, try some tests, include Photoshop resizing, include no resizing/ print driver scaling. Evaluate the results PRINTED OUT ON PAPER. Do more than one image type as well.
Tyler

[neil poulsen]

In substantial resizing using Photoshop, I go up or down in steps of about 30%. I saw photos from an small experiment that Seth Resnick contrived comparing single-step versus multi-step resizing. Multi-step produced a better result.

[Greg Miller]

In substantial resizing using Photoshop, I go up or down in steps of about 30%. I saw photos from an small experiment that Seth Resnick contrived comparing single-step versus multi-step resizing. Multi-step produced a better result.

Just use "Bicubic Smoother". That's basically what it does, but does all the work for you in one step.

[percepts]

Well as far as I can tell from people responses, the only other bit of software people have used is genuine fractals so by default that is considered the best. Might be, might not.

Have read up and GF uses its own patented algorythms but that doesn't mean they are state of the art. Also discovered that any upsizing quality using bicubic is dependant on the filters applied to the resample. Mitchell filter is the best for large up scaling but it really depends on the specific image. Don't know if PS uses mitchell filter or not. Probably but you have no control over the amount so there are undoubtedly better software packages than PS for resizing where you can play with which filter and how much of that filter is applied in the resize. Trial and error is required to get optimum results. There is no one setting which works best for all images.
Imagemagick here we come.... May not be as good as GF but my old version of PS won't run current versions of GF.

[Brian Ellis]

Well as far as I can tell from people responses, the only other bit of software people have used is genuine fractals so by default that is considered the best. Might be, might not.

Have read up and GF uses its own patented algorythms but that doesn't mean they are state of the art. Also discovered that any upsizing quality using bicubic is dependant on the filters applied to the resample. Mitchell filter is the best for large up scaling but it really depends on the specific image. Don't know if PS uses mitchell filter or not. Probably but you have no control over the amount so there are undoubtedly better software packages than PS for resizing where you can play with which filter and how much of that filter is applied in the resize. Trial and error is required to get optimum results. There is no one setting which works best for all images.
Imagemagick here we come.... May not be as good as GF but my old version of PS won't run current versions of GF.

Fred Miranda used to sell a program called "Stair Steps" that cost about $15. I don't know if it's still available or not but it should be easy enough to check his web site and see. According to George deWolfe some years ago, it's as good as Genuine Fractals and the cost is a lot less. I've never used either one, I just pass this along FWIW.

[Claude Sapp]

Brian's suggestion is a good one.

The program is called SI Pro and the purchase link is here ($24.90):
http://www.fredmiranda.com/shopping/catalogue.php

[Tyler Boley]

As Greg pointed out, bicubic smoother basically made stairstep nearly obsolete. Additionally, several other plugins have come along to compete with the more famous GF, and are worth trying as demos. Blow Up comes to mind as one I have used.
If you do some internet searches you will find several good in depth comparison articles. For PC users, Qimage must be considered at the top of the list as well, for all kinds of reasons including sophisticated scaling options.
Tyler

[George Kara]

I believe that a better description is up rez instead of interpolation. In this case the digits are duplicated. This is why some of the more sophisticated algorithms are able to do this fairly well.

[Mike1234]

Some of you will be happy to know that I give up here... with one last attempt to force my opinion on others.

Although there are tools that may do a better job of adding or subtracting pixel data and (no matter how they "label" the process) they're still just "interpolating" the missing data. No tool is a magic bullet that can add things that simply aren't there. Otherwise they could take a scan from a 135 neg and magically add enough data to make it appear as though it was scanned from a 8x10. It's simply impossible. Interpolation is a bad thing when it comes to "ultimate quality" and should never be used unless completely unavoidable. I agree with what others have said. Leave the image resolution alone and let the printer do the work. Alternatively, you can resize in PS turning OFF the "Resample Image" setting and only resize the print dimensions. This leaves the number of pixels as they are... no interpolation. However, the printer will still do its own thing anyway so it's completely unnecessary.

Or... just have a new frame made.