Sunday, September 20, 2009

VHS Scale sizes

This is the list of scale sizes I use for scaling images to make "PAL VHS" screens in The GIMP:

            Broadcast    VHS (46.25% worse)
Y   0.299R  215 x 576        100 x 240
    0.587G  423 x 576        195 x 240
    0.114B   82 x 576         38 x 240

I tend to use non-square pixel 720 x 576 images as source material, or 788 x 576 source material that I scale back to 720 x 576.

Incidentally, the type of scaling you use is important. I nearly gave up on creating VHS style images at first because I was using Cubic interpolation when scaling in The GIMP. It gives very disappointing, blocky results (click to enlarge):

Cubic scaling gives a very pixellated look

However I soon worked out that, thanks to a bit of help from a clever Hungarian chap called Lanczos Kornél, I could use Sinc (Lanczos 3) interpolation when scaling.

Lánc, Lánc, eszterlánc...

That makes all the difference to the end results. Here is the same image created with Sinc Lanczos scaling:

Hungary restores Derek Batey's honour

The sad thing is I probably spent more time on Border Television's graphics than Border Television ever did when I was writing this post...

No comments: