Tommy Blogs (retired)

Great resizing technique

For the longest time, I’ve maintained two sets of resizing actions in Photoshop: one for photos in landscape orientation (wider than tall) and one for photos in portrait orientation (taller than wide). Why? I want my photos to be resized so that the longest dimension is 800 pixels (or some other size — but I use 800 at PBase).

Somehow, I missed File->Automate->Fit Image…

I have been taking advantage of the improved downsampling algorithms of Bicubic Sharper in Photoshop CS but I had been doing it in one step and then applying the 800-pixel Multimedia Output Sharpener from PhotoKit Sharpener. That made the image way too crunchy so I reduced the opacity of the sharpening layer down to 40%.

But I’ve never been entirely happy with the result.

Before that, I used Fred Miranda’s Web Presenter Pro. It did the downsampling in 10% increments and applied its own sharpening. Unfortunately, it had rounding errors so I would end up with pictures that were 799 pixels long or 801 pixels long.

Tonight, I saw on the PixelGenius forums (only available to registered users of PhotoKit products) that Jeff Schewe recommended downsizing with Bicubic Sharper in 66% increments to get close, then use the File->Automate->Fit Image… option to complete the result.

I’ve been playing with a few pictures. The difference between this and plain Bicubic Sharper is subtle, but I can see it.

Unfortunately, there’s a slight distortion of the ratio between height and width when using the multiple-steps resizing followed by Fit Image. I wouldn’t have noticed it if I hadn’t put the two versions (single-step and multiple-step) in two layers in one image and toggled the visibility of one layer on and off so that I could compare the differences.

Given the additional convenience and improved sharpness, I think I’ll live with the very slight distortion.

Another way to compare the sharpness of two otherwise identical images is with the size of the JPEG file. In one example, the image saved with single-step resizing is 267.1K on disk while the one saved with multiple-step resizing is 279.5K.

I’m sure you’re anxious to see an example of what I’m talking about, so without further ado:

Resized in a single step

Resized in multiple steps