Resolution on demand is the current ‘in' phrase for being able to enlarge an image many fold while retaining the quality. In absolute truth, it's a myth: a pixel-based image must exhibit some adverse characteristics when enlarged 10- or 15-fold, but that doesn't matter as long as it's visually acceptable at such enlargements. pxl SmartScale is a plug-in that works with both Mac OS X and OS 9 versions of Photoshop.
It uses Celartem's PixelLive technology (based on VFZ - Vector Format for Zooming) that collects image information such as colour, brightness and edge values along with the position of any dynamic colour changes. On enlarging, it makes use of this data to maintain an image's colour and sharpness.
The first thing that strikes you on opening up a picture is how good the plug-in's user interface is. The full-screen window shows the preview image, and includes a pair of scrollbars and a movement hand tool. Also, there's a floating navigator palette that sports the customary slider for zoom area with a displayed percentage figure, and two allied buttons to move through the key percentage views. Alternatively, there's a magnifying glass tool for manual zooming.
The image-size palette offers three ways to enlarge an image: by percentage or pixels for width and height, by setting the required final document size, or via a slider that goes from Small to Large. On selecting the crop tool and dragging out an area, the crop palette comes into play, in real-time.
The detail palette holds four post-scaling refinement functions that set pxl SmartScale apart from other image enlargers. Overall Sharpness controls the amount of applied sharpen or blur through four levels. The other three, Edge Contrast, Edge Detail and Extreme Edges, all work on areas of heavy colour shift. The results of any changes are displayed in the main preview window, again in real-time.
The comparison with Genuine Fractals Print Pro 3 is an obvious one. Print Pro is more expensive, has a limited user interface - and LizardTech has been recently acquired by Celartem Technology, the owner of Extensis. I'll leave you to draw your own conclusions there.
In tests, the results from pxl SmartScale were pretty well on a par with Print Pro. But the vastly superior user interface coupled with the post-scaling detail palette, optional password-protected image format and an ability to open images directly from disk put pxl SmartScale on top of the pile.