Photoshop batch-filing: sharpen image?

[mbalensiefer]

Hi!
 
 I have many images at 2000-3000 pixels in height. SOME are only 700 pixels in height. When displayed/hosted online, I'd like these images to appear "crisp;" some of them appear fine on my monitor when ACDSee's auto-downsized them...but they then look blurry on the edges (and in detail areas, like in faces) when "really" resized through Photoshop. Final files should be around 600 pixels in height.

 Should I batch-file an edge-sharpen? What is your favorite tool? My dilemma is that I am working with different-sized images before resizing them. Most of them, however, are quite large.

 Thanks again,
~Mike

[Mark D Segal]

I don't know anything about ACDC. However, when you resize JPEGs repeatedly and resave them, lossy compression occurs and those image sizes in 8 bit depth the information loss will noticeably degrade the images. Start with large images and downsize them in Photoshop using Photoshop's Bicubic Sharper resampling option. It does a fine job even on very large down-sizing.

[mbalensiefer]

"Bicubic Sharper." Got it.
 Out of curiosity, is this also what you'd use pre-printing?

~Michael

[Mark D Segal]

It depends on the print size and resolution. If you are increasing pixel dimensions in order to print you would use Bicubic Smoother, or for decreasing pixel dimensions use Bicubic Sharper.

[mwr]

For downsizing to a bounded rectangle, that is to fit within a rectangle of a certain pixel size, I use Photoshop's Automate>Fit Image, then sharpen the result with Smart Sharpen. I record and save an action with those steps, then run that action via Automate>Batch. You have to experiment first to determine the sharpening settings you prefer.