changing a photo's dpi resolution on a MAC

I'm working on a slideshow for a wedding and all of my pictures are HUGE. I've changed the image size but still need to decrease the resolution. Is there a way to do this on a mac? Thanks in advance.

Photoshop / Image / Image Size (type in your desired DPI in the "Resolution" box).

BTW...I would have done this FIRST before resizing the pics.

Joey

When life gives you dilemmas...make dilemmanade.

how do you batch resize a bunch of images in photoshop so i dont have to redo them all one by one. thanks

Photoshop has a "batch" tool which will remember something you do to a picture and then do it repeatedly to a number of pictures.

I wrote up a brief tutorial for Photoshop 5, but every new Photoshop is slightly different.

[www.kozco.com]

That will give you the idea. It is covered in the photoshop instructions. It's a very thinly disguised programming language, so if you speak COBOL, you'll be right at home. If not, you may be writing down some steps on a notepad as you go.

Koz

There's no reason to change the DPI of a file - it has no meaning in video.

Martin Baker
[www.digital-heaven.co.uk]
Unique plug-ins and tools for Apple Pro Apps

<<<batch resize >>>

Yes, you do need to actually resize the pictures, not just change the dpi. Video doesn't use dots per inch. Video isn't paper and it doesn't have inches.

Someone correct me, but doesn't Final Cut "know" what a 720x540 picture is and automatically fit it into the show? There's one condition where FCP does something useful to make up slight errors.

Koz

Changing the DPI DOES AUTOMATICALLY change the image size if all is linked in the Image Size dialogue. If you start out with a 3000x2025 pixel / 300 DPI image (6.75 x 10 inch still) and you change the DPI to 72, you get a 720x486 / 72 DPI image (still a 6.75 x 10 inch still) that is much more managable (file size wise). Only downside is you can't blow it up without losing resolution.

Joey

When life gives you dilemmas...make dilemmanade.

[Only downside is you can't blow it up without losing resolution. ]

Aye there's the rub!!

Scan and resize intelligently based on creative need.

- Loren
Photo scan rates demystified!
ScanGuide? Pro compact reference.
Now available at discount at the LAFCPUG Store!

There's a great way to program a "batch" downsize of pictures using Apple's built in AUTOMATOR program -- it has all the actions built in

Good tutorial on how to do this is here:

Resizing with Automator Tutorial

btw Larry Jordan has an excellent article on the "sweet spot" sizes for pictures to do pan and scan inside FCP

go here for information

Larry Jordan Web Site - Photoshop Sizes

but for those of you who don't care to click - here's the reader's digest version

(From Larry Jordan's Site)

* A good image size for pan-and-scan in 4:3 NTSC is 1800 x 1350 x 72.
* A good image size for pan-and-scan in 4:3 PAL is 1920 x 1440 x 72.
* A good image size for full screen 4:3 NTSC is 720 x 540 x 72.
* A good image size for full screen 4:3 PAL is 768 x 576 x 72.

This is a wonderful recipe for a batch of identically dimensioned pieces.

Larry will confirm, these formuli relate to a single size of image. But in the real world, one minute you have a 2" wallet photo, the next a 14" wide roadmap. You will not successfully apply a general dimension or scan rate to disparate sizes. You'll either scan too little or too much.

For a bunch of photos and flat art with wildly varied dimensions, utilize a system designed for real world scanning or resampling.

- Loren
Photo scan rates demystified!
ScanGuide? Pro compact reference now at
www.neotrondesign.com

My experience is when the client says (can you use these digital photos) they tend to be all the same enormous size -- so Loren's right -- the sizes and automation work best if this is the case --