To do the pleasantville effect you first have to film a scene that has at least one bright colour that stands out. Once you have got this colour and filmed properly you then upload your film to final cut pro. You then selected the part of your film that you want this effect on. You then click effects and go to video filters, then click on colour correction, then colour correction 3-way. Drag this effect onto your film. Once you have done this get your film up next to the colour correction effect. You need to get the dropper and click on the colour you want to stand out. The slider should then automatically go to that colour. Make sure you click off the 'luma' and 'sat' and make sure your sat is turned all the way to the left. You will then need to invert the colour corrector. By pressing the invert selection button. This is two buttons under the dropper it looks like a trapezium. You will then need to render your video. Repeat this on any part of the film you want this effect on.