Resizing - Is interpolation a sign of the past?

12/21/2003 11:54:44 PM · #1

Slightly misleading title, ran out of characters, should really be "intermediary interpolation" ... but, with that in mind .....

Taken directly from a document from Adobe on Photoshop CS that covers new features that got less press than they might have:

And I quote (minor edit for tired fingers):

There are two new interpolation algorithyms for resizing images. Both are based on bicubic interpolation, but focus on keeping the image smoother or sharper - "Bicubic Smoother" and "Bicubic Sharper". Typically Bicubic Smoother works better on images you need to enlarge and removed the need for intermediary interpolation and Bicubic Sharper where you need to downsize.

So, I wonder how these do compared to doing it in 5% steps.

It would be silly to do it in 5% steps if it makes no difference, or potentially does not even do it as well.

Thoughts on this people?

Message edited by author 2003-12-21 23:55:58.

ahaze

12/22/2003 06:17:42 PM · #2

would anyone who has tried it in PSCS be able to post some results from both CS and 5% for comparison purposes? I'd sure be curious.

Canon EF 400mm f/5.6L USM

12/22/2003 07:49:13 PM · #3

Same here, I'd love to know if people have done a comparrison.

I'm not good enough to be able to spot the difference usually anyway.

Refracted

Canon EOS-50D

12/22/2003 08:11:39 PM · #4

I did a little test.. i'm not sure what would be best..

Original:

using Bicubic Sharper:

using Bicubic Smoother:

using 5 percent increments:

Refracted

Canon EOS-50D

Canon EF 400mm f/5.6L USM

12/22/2003 08:14:07 PM · #5

after looking at them for a bit (flipping through the pages looking at each), it seems both smoother and sharper are blurrier than the 5% method, but the 5% method doesn't seem to keep it's shape, because of the constant "rounding off" caused by each resize step, it is sharper though, but does increase haloing (around the finger)..

PS: the original image is am untouched 100% crop of a 5 mp image.

Message edited by author 2003-12-22 20:22:16.

dacrazyrn

Nikon D300

Nikon AF-S DX NIKKOR 18-200mm f/3.5-5.6G ED VR II

12/22/2003 08:28:17 PM · #6

I think the 5% still looks better. what about doing the 5% with smoother and/or sharper? Any difference?

KevinRiggs

Canon EOS-1Ds

Canon EF 70-200mm f/2.8L IS USM

12/22/2003 08:42:14 PM · #7

Just an FYI -

Scott Kelby in his book, the photoshop cs book for digital photographers(capitalization his), suggests Jim DiVitale's trick of using Bicubic Smoothing but only doing it in increments of 10% (pp 75-76).

Edit - Oh yeah, and he suggests assigning this as an action and creating an F-key shortcut so that you can easily rez up an image via keystrokes. And before Kelby, DiVitale or New Riders gets concerned, let me suggest that you pickup this book. Kelby's writing is good and enjoyable to read (if you like a sardonic wit every few pages) while his reference to keystrokes in a personal manner of usage lends credibility to his authority with the Photoshop software. It is worth the $39.99.

Message edited by author 2003-12-22 20:45:09.

Canon EF 70-200mm f/2.8L IS USM

12/22/2003 08:46:33 PM · #8

Hey Kevin ....

Am thinking of getting that book. Would you recommend it?

I am a reasonably experienced PS user, but not an expert. I can usually manage to do what I want to do, but often find there are easier ways of doing it than I am attempting. Worth getting for me you think?

Nice work there Refracted. I can see a difference, but not enough that I would notice unless I was deliberately hunting for the difference. I think that may just be my lack of experience with it though.

Message edited by author 2003-12-22 20:47:55.

KevinRiggs

Canon EOS-1Ds

12/22/2003 09:24:07 PM · #9

The book is written in a workflow manner with the first 2 chapters being on the use of the FileBrowser within Photoshop and how to customize it for you particular methodology. The book is very in-depth on multiple ways to setup your copy of PSCS to accomplish some of the most common tasks. Kelby seems to be very familiar with PS and he shares several comments from other people who are probably well known in the digital photography field. The only one that comes to mind is Jim DiVitale (just cause I looked up his tip). Don't expect to find every filter mentioned or every layer but if you want a good book that will show you several tricks and help you refine your workflow after seeing how the author just glides from one step to the next via keystrokes or actions he has saved, then this book contains useful information and is a good resource for helping you get familiar with the little extras that PSCS throws in. I've already cut down on my time editing some images and I didn't have to dig through several chapters about stuff that I won't use. I've read pretty much straight through the book.

Annnnndddd, if you like a sharp, sardonic wit, please be sure to read the chapter introductions. Kelby is a smartass when it comes to writing the "non-essentials" like an introduction. He's dead-on when it comes to sharing methods for accomplishing editing tasks that you're likely to need to do.

All-in-all, if you're familiar with PS but you know that there are little tricks that you just haven't found and no one's shared them with you, then this is the book that can help you while it teaches you some new features of PSCS.

TechnoShroom

Canon EOS-30D

Canon EF 100mm f/2.8 USM Macro

12/22/2003 09:55:11 PM · #10

Originally posted by Natator:

So, I wonder how these do compared to doing it in 5% steps.

I've seen this 5% mentioned before on this site. Where did this come from? I've only ever heard it here. Everywhere else, including Adobe, says resizing in 10% increments works best. Is the 5% you mention something new?