Learn more about how our offline upscale processes files secure and fast.
Standard browser resizing uses linear interpolation, which makes edges blurry. Our Lanczos-3 filter maps pixels using mathematical sinc weights ($Sinc(x) = sin(\pi x) / (\pi x)$) with a kernel window of $a=3$, yielding sharp, edge-preserving upscaling.
Lanczos upscaling performs complex mathematical calculations for every single pixel. Since this runs on your local CPU thread, upscaling a large image to 4x or 8x requires processing millions of pixels, which may take a few seconds.