A simple web search shows that many photographers have found that stepwise or stair interpolation is superior to Photoshops single step bicubic interpolation, and many are still using the technique. Some even offer free tools to work with 16 bit images. In fact I haven't seen a site that categorically says that it's harmful to an image. Hell the only way it could be is if you overwrite your original file. Most recommend it up to 400% size increase, (well within the range that Dave is working in). Hell if I were making the print I'd do both print a test of the most important part of the image to see which method worked best and go from there. By the way Dave this guy has a Photoshop action that should make the stair interpolation almost painless, (and it's hell of a lot easier to use than the one I wrote for myself).
http://homepage.ntlworld.com/nick.thomas93/interpolation/interpolation.htm [EMAIL PROTECTED] wrote: > I've seen Fred's plug-in plug. I think he's one of only a few who still > consider stepping to be a good method. For normal upsizing a straight Bicubic > Smoother interpolation compares very favorably to a fractals job as well. > Fractals is at its best when you have to go extremely large. The art > directors I work with specify it when interpolating an MF shot for a 50-foot > billboard. That's where it shines. > Paul > -------------- Original message ---------------------- > From: "P. J. Alling" <[EMAIL PROTECTED]> > >> Perhaps you should tell that to Fred Miranda, who sells a Photoshop >> plugin. to do Stepwise, (or as he puts it stair), interpolation, and >> seems to be well respected for his results. He even supplies samples to >> compare results between his SI method and Genuine Fractals. I'm not >> sure where Greywolf is coming from. By my quick mental calculation >> using a 300 DPI as a standard then Dave is looking at more of a 3-4x >> linear increase in size which implies that some care should be taken. I >> usually settle for 250 dpi for my prints but this is for presentation... >> >> [EMAIL PROTECTED] wrote: >> >>> Exactly. And upsizing in steps has been shown to be destructive. Every >>> >> interpolation introduces some error. You only multiply the problems by >> stepping. >> >>> Paul >>> -------------- Original message ---------------------- >>> From: graywolf <[EMAIL PROTECTED]> >>> >>> >>>> The point everyone seems to be missing is that this is only a 2x upsize at >>>> >> the >> >>>> most. No need for a lot of exotic stuff. And I have not noticed that GF or >>>> Stepping does all that much better than Bicubic Smoother. Converting from >>>> RAW >>>> >> is >> >>>> a bit better, but not miraculously so. While I do not print 16x20's I do >>>> >> often >> >>>> crop that much. This is not rocket science, for crying out loud. >>>> >>>> graywolf >>>> http://www.graywolfphoto.com >>>> http://webpages.charter.net/graywolf >>>> "Idiot Proof" <==> "Expert Proof" >>>> ----------------------------------- >>>> >>>> >>>> P. J. Alling wrote: >>>> >>>> >>>>> I think it would depend on three things. 1.) Subject matter, a very >>>>> detailed photo will loose a lot upresed that much, while a less detailed >>>>> shot might be fine. 2,) Viewing distance. If viewed from a reasonable >>>>> distance it will look fine. Close up flaws will be very apparent. 3.) >>>>> The method used to upres the shot. Genuine Fractals is supposed to work >>>>> miracles, stepwise bicubic interpolation is supposed to work almost as >>>>> well, (and is available to anyone willing to make a Photoshop action). >>>>> You could try resizing using the second method to get a reasonable pixel >>>>> density for your purposes then crop out a sample size and print it to >>>>> see if it would work. >>>>> >>>>> David J Brooks wrote: >>>>> >>>>> >>>>>> I can't seem to fiqure out the math on this and don't want to quess, >>>>>> but can anyone tell me what size i need to uprez a 2000 x 1300 file to >>>>>> print 16x20. >>>>>> >>>>>> If a 2.74 D1H file can be resized that big. >>>>>> >>>>>> A client wants this size for her company wall. >>>>>> >>>>>> Dave >>>>>> >>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>> -- >>>> PDML Pentax-Discuss Mail List >>>> [email protected] >>>> http://pdml.net/mailman/listinfo/pdml_pdml.net >>>> >>>> >>> >>> >> -- >> All dogs have four legs; my cat has four legs. Therefore, my cat is a dog. >> >> >> -- >> PDML Pentax-Discuss Mail List >> [email protected] >> http://pdml.net/mailman/listinfo/pdml_pdml.net >> > > > -- All dogs have four legs; my cat has four legs. Therefore, my cat is a dog. -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
