image resizing?

Cybix

macrumors 6502a
Original poster
Feb 10, 2006
993
1
Western Australia
I'm trying to figure out the best way (quality) to resize images in OS X.

i've highlighted a pile of files and setup an automator workflow to scale the images, using 'preview', and the quality of the result is rubbish. all chunky and pixelated...

is there a better way? I need to resize LOADS of pics before uploading them to my coppermine photo gallery... :(

James
 

Cybix

macrumors 6502a
Original poster
Feb 10, 2006
993
1
Western Australia
not an option, I dont need to do any image editing, and hate trial-ware.

I'm tempted to buy apeture though... does it batch resize? :) do i need a 30" acd to go with it? rofl
 

20rogersc

macrumors 65816
Jun 28, 2005
1,144
0
Brighton, UK
Put them all in to a Album in iPhoto.
'Cmd-A' or highlight them all.
'Cmd-Shift-E' or 'File-Export' (I think).
Then change the file size, and chose folder.

I think this will export them all at once!?
Sorry, not on my iBook to check!

::20ROGERSC::
 

gauchogolfer

macrumors 603
Jan 28, 2005
5,555
5
American Riviera
20rogersc said:
Put them all in to a Album in iPhoto.
'Cmd-A' or highlight them all.
'Cmd-Shift-E' or 'File-Export' (I think).
Then change the file size, and chose folder.

I think this will export them all at once!?
Sorry, not on my iBook to check!

::20ROGERSC::
Yep, this would work fine. I use it to export pictures to a website of mine all the time.
(You even got the key combos right ;))
 

Cybix

macrumors 6502a
Original poster
Feb 10, 2006
993
1
Western Australia
back on this...

resizing my images using iPhoto still pixelates them, they look aweful when they have been exported, perhaps there's a hidden quality setting somewhere? Same story when using the automator to do it.

at this stage I have to use some canon software that came with my camera to resize pics and keep them looking good. Unfortunately it only lets me do one pic at a time.

the quality out of iPhoto is just not there. Say my pic is 3xxx px in size, and I resize down to say 1440 (or whatever), it looks great until I click on 'actual view' in iPhoto, and see all the chunkyness, it's like a jagged edges pixelation problem...

help?

I could try post some examples
 

snickelfritz

macrumors 65816
Oct 24, 2003
1,109
0
Tucson AZ
Save an Action as a Droplet on your Desktop from Adobe ImageReady.
"Resize Image" and "Set Output Folder" are the two functions you need in the action.
You can then simply drag the images onto the droplet and they will be resized and saved in that folder.
 

CanadaRAM

macrumors G5
GraphicConvertor will also allow you to batch operations.

Keep in mind that resizing from 3000 px to 1400 px means you are throwing away 3/4 of the pixels in the document. If you look at it at the same viewable size onscreen, you WILL have pixels that are 2x and tall and 2x as wide as the original.
 

clintob

macrumors 6502
Feb 16, 2006
255
0
New York, NY
There's a reason Photoshop is inordinately more expensive than it's counterparts, and it's only partially to do with all the "other" tools. One of the main advantages of Photoshop is it's ability to resize, rotate, and alter images with little or now loss of quality. It has a very sophiticated engine for resizing, and thus, costs more.

If you want the same quality for less bucks, get Photoshop Elements. It'll do the job for resizing and such just as well as Photoshop, and you don't have the clutter of all the tools and filters you wont use. And it's a LOT cheaper.
 

snickelfritz

macrumors 65816
Oct 24, 2003
1,109
0
Tucson AZ
I resized a 3000 pixel image in Photoshop and a copy of it in iPhoto.
Placed the photos on separate layers in Photoshop to facilitate rapid comparisons at 500% zoom.
If there was a significant difference in quality/pixelation etc..., I couldn't see it.
 

clintob

macrumors 6502
Feb 16, 2006
255
0
New York, NY
snickelfritz said:
I resized a 3000 pixel image in Photoshop and a copy of it in iPhoto.
Placed the photos on separate layers in Photoshop to facilitate rapid comparisons at 500% zoom.
If there was a significant difference in quality/pixelation etc..., I couldn't see it.
Yeah, that's true. Just keep in mind that it will vary a bit from image to image, and is heavily dependant upon the color space, resolution, and subject matter of your original photo. iPhoto downsamples most images to it's standard 8-bit RGB settings, which is fine for 99% of users. The real advantage to Photoshop is its ability to work effectively in multiple color spaces, at very high resolution, and with 16-bit image files, so you end up getting a bit better dynamic range.

However, in the end you're right. Unless you're a real stickler for details, or have a loupe in hand, you're not going to notice a tremendous difference in most tasks. The differences become noticeable when working with large, high-res files for print. You'll see the differences there, but again, it's not life or death, especially for consumer stuff (3x5 / 5x7 / 8x10 photo printouts).
 

snickelfritz

macrumors 65816
Oct 24, 2003
1,109
0
Tucson AZ
clintob said:
Yeah, that's true. Just keep in mind that it will vary a bit from image to image, and is heavily dependant upon the color space, resolution, and subject matter of your original photo. iPhoto downsamples most images to it's standard 8-bit RGB settings, which is fine for 99% of users. The real advantage to Photoshop is its ability to work effectively in multiple color spaces, at very high resolution, and with 16-bit image files, so you end up getting a bit better dynamic range.

However, in the end you're right. Unless you're a real stickler for details, or have a loupe in hand, you're not going to notice a tremendous difference in most tasks. The differences become noticeable when working with large, high-res files for print. You'll see the differences there, but again, it's not life or death, especially for consumer stuff (3x5 / 5x7 / 8x10 photo printouts).
I think the original problem is probably related to something other than a flaw in resizing algorithms.
IMO, Photoshop is an excellent investment for anyone who works with images on a regular basis.
It's undeniably expensive, but the overall product satisfaction is enormous.
And it does a really fabulous job of resizing images.
 
Try sips from Terminal or alternatively download imagemagick.

I have only used the former a little but is included with OS X.

The second I know has many, many features and you will be able to apply all sorts of filters to ensure you maintain quality.

Both are free.

As both are command line apps, they are trivial to script for large numbers of files.