[ Techniques ]
Print Color Images On Any Paper Color
Creating a "reflector" for color toner
As mentioned in the opening page, toners are transparent. The reason color images look so good on white paper is the fact that light passes through the translucent color toner and is reflected off the white paper to then carry the perceived color back to your eye. Light doesn't just bounce off the toner! The image here on the left dramatically demonstrates just how transparent color toner really is. We made two identical columns side by side but the right column does not have a white reflector under the color toner image so it all but disappears.
Here's what's going on...
Let's look at the basics to get an understanding of the problem to be able to fix it. Let's say you have a big red circle drawn on your monitor and want to print it on a yellow sheet of paper. What happens is, light hitting the paper goes through the red toner, reflects off the yellow background, picks up the red toner on the way back to your eye and gives a perceived color of orange ... all day long!
So how to fix this? Simple! Create a white reflector base for the red circle! To do this, we need to create a fake background of white over the yellow paper in the exact spot where we want to print the red circle. This fake background is called a "knockout". First create a duplicate of the red circle on screen (normally done by making a new layer) and fill it with black. Very important! Now select the black circle and add a "1 point" white line with the option called "Inset" - meaning the 1pt line you're adding encroaches INTO the circle's perimeter. Doing this will make the black circle show on the left a tad smaller since the white line obviously won't print. Now add the white foil over this black circle and you have the image shown on the right. This process is called "trapping".
So we've put the white circle on the yellow paper squarely back into the printer's manual feed tray and print the red circle. The color image will now print in the exact same spot with a very slight overlap that you won't detect. Color toner will print beautifully over all foils. The key to "trapping" the knockout is to prevent any white from showing around the graphic due to very minor mis-registration, common on all laser printers. Having any white foil creep out from under the color will make everything look terrible.
Setting up your artwork to do this "trapping" is normally done in a graphics type application like Photoshop, Illustrator, CorelDraw, etc - any graphics program that has "layer" control. If you're not familiar with "layers" it's all quite simple. Layers are just that... a stack of identical images you can turn on or off when it's time to print. We understand this may sound complicated, but once you try it you'll get a full understanding of how simple it really is and the power the white foil gives you. WhiteTRF foil ... because white is the one color you just can't print!
Customers have asked, "Why don't you just carry pigment color foils so we can transfer a solid foil color like red?" The simple reason is that color laser printers (and color copiers) can reproduce 16.7 million colors with just Cyan, Magenta, Yellow and Black toner cartridges. Granted, 16.7 million shades isn't a lot (your eye can discern about 10 times that number) so it comes down to logistics. Why try to replicate what already exists for doing the short color spectrum? Nobody could offer 17 million pigment foil colors! If we had 10 shades of red, someone would want another shade! Since we can now master color on dark backgrounds, you've got the best of all worlds to be able to print WHITE, a dozen METALLICS and basically FULL COLOR. That's a powerful capability all around!
Black circle printed on yellow paper
Red circle on Screen
Result of printing a red circle on yellow paper
Vibrant red circle over yellow paper
White foil applied over the black circle