How to create perfect Laser film

A question I often get asked is "how do you get your Laser Film to register perfectly?"
A basic explanation of how laser printer works is, a sheet of film is taken into your laser printer and an electrical charge is laid down onto the film in the image of your design. This electrical charge acts like a magnet for the black toner which sticks to this charge. The toner is then fused to the film with heat, it's this heat process that distorts your film, not by much but enough to alter out your registration. The problem isn't, that the film shrinks, the problem is, that often it doesn't all shrink the same amount, and it is this variation in shrinkage that upsets your registration.
Different brands of laser printer do this fusing of the toner at different temperatures and you obviously want one that does it at the lowest temperature giving you the least amount of distortion. When buying a laser printer take in some sheets of film and do your own registration test before you buy. It is important to have a good laser printer, and equally to have good laser film. OK now you have the right equipment but it doesn't end there, your laser printer is still going to shrink your laser film even if it's only a fraction. What you must do is set up the exact same conditions for each sheet of laser film so you will get the same shrinkage on each one. What I mean by that is if you have a 5 color design to print out, and you load in film and tell your printer to print these out automatically one after the other, the time delay between each sheet of film printing depends on the amount of information in that color channel, for example if you print out one color channel that has a lot of color on it and the next channel only has a small amount of color on it, the delay between printing out the two sheets of film is almost nil, whereas a channel followed by another with a lot of color information on it make have a 10 or 20 second delay between printing each sheet of film (depending on the memory of your printer). During this time delay your laser printer is cooling down giving a slightly different temperature for the next sheet of film so the shrinkage will be slightly different. All this sounds complicated but it's very simple to resolve.
If you want perfect registration never print out all your film automatically you must print out each color channel individually. This may take an extra 10 minutes but the results are worth it.
Before you begin printing out your film always print your separations on paper first just to make sure all is well before using the more expensive film, this will also warm up your laser printer (never start printing film from a cold laser printer).
Next select the first channel only and print it out, collect the film as it comes out and lay it down somewhere flat to cool down, then print out the next channel and so on until all are finished. Do not stop and go have a coffee break in between once you start you must finish, remember it's all about consistency.
If you do all this, use good film and it still doesn't register it's probably your laser printer and you may have to upgrade.