All these charts use Humbrol paints as the bench-mark, so if you want to convert from Heller to Vallejo then you'll have to go via Humbrol.
I have tried to be as accurate as possible but I have to point out that the conversions and the colours used in the charts are to be used as a guide only as it is impossible to be totally accurate for several reasons mainly because monitors, printers and the good old fashioned human eye vary so much. Anyway, I hope these prove useful to you.
Click on the logo for the brand you wish to view (Revell, for example) and you'll see a two charts, one converting from Revell to Humbrol and one converting from Humbrol to Revell. If the image is too small then just click on it to zoom in.
The following charts have now been moved to our new website: