Posted by Jack Garrett on January 22, 2008 at 12:58 AM
I have a client who wants a larger size image. My camera raw file size is 9mp at approx 9 x 14 inch and 240 pixels/inch. I need to get this to 18 x 24 or whatever it calculates to (18x27) I think. I tried resizing using bicubic smoother in CS3 and the image doesn't look so hot....any suggestions? I heard someone say once that you could enlarge by 10% increments and the image would stay sharp..is that true?
Posted by Ken Wyatt on January 22, 2008 at 1:13 AM
Enlarging in steps is debatable. Some think it makes a small difference - some say don't bother (Tim Grey, I believe). I've successfully enlarged to 24 x 36 without any problem (from 6MP JPEGS, no less). Are you keeping the resolution at least 240? I normally use 300 and just let the bicubic do its thing. The one thing I -always- have to do is reduce the noise with software like Noise Ninja or Neat Image (which is the one I use).
Could the image just be not sharp to begin with?
Ken
Posted by Paul Wegemann on January 22, 2008 at 8:49 AM
John,
I use Qimage and have had great luck. It's pretty inexpensive, and if you're selling images, probably well worth the cost. One thing you didn't mention is if you'll be printing this yourself. If so, then Qimage of one of the other uprezing packages might be worth a look. If you're having a lab print for you, then you should talk to them as some folks feel that the hardware uprezing in the lab printers is better than what you can to at home.
BTW, in his latest CS3 book, Scott Kelby has a slightly different method that works well - Basically, you use Bicubic Sharper (not smoother) and 360 dpi to upsize. He claims this works as well as any of the software packages you can buy.
Posted by Kalin Wilson on January 22, 2008 at 10:40 AM
I use Qimage or the DOP Upsize action. You should try a few techniques as upsizing is very image specific in my experience. I just checked the DOP filters page and I don't see the upsize plugin download link. I also can't find my copy. So maybe someone has a copy they can make available for download.
Qimage has a trial period but prints an overlay on your images. See the tutorials for how to upsize without printing.
Good luck!
Posted by Stan Rose on January 22, 2008 at 12:36 PM
I have compared a 10% step method to simple one-step bicubic and it sure looks way better to me, which is why i always use a step method.
Posted by Nat Coalson on January 22, 2008 at 3:35 PM
Jeff Schewe's article in Digital Photo Pro is the definitive resource on this.
I don't see the need to use anything other than Photoshop for resampling.
Sometimes I use a step method (50% in two steps), other times all at once. Depends on the image.
But in general you're better off using as few resampling steps as possible to avoid too much damage to the image data.
For upsampling, somtimes Bicubic Smoother is best, other times straight Bicubic produces the best results.
Sharpening is a critical step in resampling; too. Sometimes it's good to go halfway, sharpen, then go the rest of the way.
Always work on your master file at native resolution; only resample as necessary for printing, and save those derivative files if you'll need them again. Don't resample your master file.
Posted by Stan Rose on January 22, 2008 at 4:43 PM
But in general you're better off using as few resampling steps as possible to avoid too much damage to the image data.
Thanks for that info Nat, but could you explain--how would too may resamples damage the image? It seems to me (to use an analogy) that a bicubic sample in one step would be like cramming too much stuff trough a small tube. It seems intuitive to me that less damage would be done taking it in increments.
Posted by Nat Coalson on January 22, 2008 at 7:09 PM
Each time you resample the image, the data is modified. And with raster images, any time data is modified, some is lost, due to what's known as "rounding errors" in floating point CPU operations.
Put simply, each time an image is resampled, data is lost. And it's not recoverable (unless you go back in history, but then you lose your resizing, too.)
Depending on the image, the degradation may not be easily visible, but it's there.... Consider that every resampling involves interpolation during which pixels are either synthesized or thrown out. Either scenario is destructive to the image data.
If you want to maintain the absolute highest quality in your images, don't resample them more than 2 or 3 steps. And never go up and then back down (or vice versa).
Posted by Stan Rose on January 23, 2008 at 12:17 PM
Discussion
9 repliesCould the image just be not sharp to begin with?
Ken
I use Qimage and have had great luck. It's pretty inexpensive, and if you're selling images, probably well worth the cost. One thing you didn't mention is if you'll be printing this yourself. If so, then Qimage of one of the other uprezing packages might be worth a look. If you're having a lab print for you, then you should talk to them as some folks feel that the hardware uprezing in the lab printers is better than what you can to at home.
BTW, in his latest CS3 book, Scott Kelby has a slightly different method that works well - Basically, you use Bicubic Sharper (not smoother) and 360 dpi to upsize. He claims this works as well as any of the software packages you can buy.
Paul
http://www.digitalphotopro.com/tech/the-art-of-the-up-res.html
Qimage has a trial period but prints an overlay on your images. See the tutorials for how to upsize without printing.
Good luck!
I don't see the need to use anything other than Photoshop for resampling.
Sometimes I use a step method (50% in two steps), other times all at once. Depends on the image.
But in general you're better off using as few resampling steps as possible to avoid too much damage to the image data.
For upsampling, somtimes Bicubic Smoother is best, other times straight Bicubic produces the best results.
Sharpening is a critical step in resampling; too. Sometimes it's good to go halfway, sharpen, then go the rest of the way.
Always work on your master file at native resolution; only resample as necessary for printing, and save those derivative files if you'll need them again. Don't resample your master file.
Thanks for that info Nat, but could you explain--how would too may resamples damage the image? It seems to me (to use an analogy) that a bicubic sample in one step would be like cramming too much stuff trough a small tube. It seems intuitive to me that less damage would be done taking it in increments.
Put simply, each time an image is resampled, data is lost. And it's not recoverable (unless you go back in history, but then you lose your resizing, too.)
Depending on the image, the degradation may not be easily visible, but it's there.... Consider that every resampling involves interpolation during which pixels are either synthesized or thrown out. Either scenario is destructive to the image data.
If you want to maintain the absolute highest quality in your images, don't resample them more than 2 or 3 steps. And never go up and then back down (or vice versa).