Image Scaling

The image viewer always uses the anti-aliasing method.

Three different scaling methods are available for conversion. You select scaling method in the Image Size dialog.

Pixel Replication

This is a fast method. However, it may lead to blocky images for large scaling factors (example 1).

 

Interpolation

This method employs bilinear interpolation between four neighboring pixels. This method is slower than pixel replication. It reduces the blocking by making more smooth transitions at the expense of sharpness (example 2).

 

Anti-aliasing

This is the default interpolation method. It performs anti-aliasing without reducing the sharpness significantly.

Anti-aliasing is the technique of minimizing aliasing (jagged or blocky patterns) when representing a high-resolution image at a lower resolution. It smoothes the on-screen appearance by filling jagged pixels with intermediate color or shades of gray to increase clarity.

It is recommended for downscaling and for scaling of images containing patterns, for example, images scanned from a printed source (example 2). Also images with thin lines (example 3) should be scaled using this method. For large scaling factors it induces the same blocking artifacts as pixel replication (example 1).