The surface reflects all the visible colors of the spectrum, and we see pure white light. Of course, it is worth to clarify: in the printing industry there is no absolute white color. With traditional printing, the white color is either the color of the paper or the white printing.
When the designer leaves the object or background white, when printing, it often means that there will simply not be paint. This color will be “conditionally white” – the paper can be bluish, ivory or slightly greyish (color of the marengo). If you combine sheets of different types of paper, you will see how they differ among themselves with shades of white.
And yet on any paper the absence of paint creates a noticeable contrast and we see an object of white color.
But here can be exceptions: the paper itself may not be white. Kraft, packaging paper, colored designer papers and cardboards, foil surface, transparent plastic – here the absence of paint does not help to reproduce the white color.
For example, when printing on an orange design paper, the object that was on the screen was white, it will be … orange in print. It is for such cases that a special paint is used – white.
We all used whitewash in our childhood – remember a jar of white gouache, from which New Year snowflakes were born? In polygraphy, white paint is taken when white objects are to be painted on a colored background.
Experienced designers prepare a layout for printing on colored paper, using a color background in Photoshop. So they see where you need to enter white paint to achieve the desired effect. When color separation, a separate form is created for the white paint, white is charged to the print unit – and the white elements are printed exactly the same as all the others. When printing with white, you need to carefully monitor the order of application of colors (this is usually the concern of the technologist).
Sometimes white is the main color (or even the only one). The designer can create a monochrome drawing – for example, to conceive the printing of New Year’s greeting cards with white color on dark blue corrugated paper. Or use several immiscible colors – for example, white, gray and gold.
Another type of printing, which uses white paint – silkscreen. This is a special technology, here the colors are rarely mixed, each color is applied separately, and white is used quite often.
Agree, the folder of a thick dark cardboard with a slightly convex to the touch logo printed with white, will look more presentable than the same folder, printed on ordinary thick paper, where the logo will simply turn in a dark background.
There is one problem when printing on a color background or transparent plastic – accurate reproduction of full-color images.
The color background distorts almost any paint. Only silk-screen printing uses opaque inks – they are completely opaque and look the same on any background. With offset and digital printing, the image is formed from small (almost invisible to the eye) points, that is, the background always participates in the formation of the image. And the lighter the color (the less often the points), the more the background will be visible.
Remember the printing of cards on orange paper. It is easy to imagine what will turn into, for example, the blue color on the orange – the colors will add up and the blue will become dirty green.
Naturally, no one needs this effect – unless the designer has conceived this layering of colors in advance.
To get a bright natural full-color image on a colored or transparent background, you must first print a white substrate. Simply pour a piece of paper on the white so that other colors lie on the usual white background.
When printing on transparent plastic, a white substrate will avoid the “stained glass effect” – the colors will not shine through. Pay attention – they print almost all the packaging: first white, for them – a full-color image.
With this approach to printing on color and transparent materials, the designer will not have any problems with color correction. Full-color images will be reproduced quite expectedly, without distortion. The only point to be considered is the printing of white (that is, a separate paint for the substrate). On a 4-sectional offset machine this will be a separate run, on a machine with five or more sections – one section will print with white.
With digital and offset printing on colored paper or cardboard, as well as on plastic, running white paint is almost always necessary – unless you want to achieve a stained-glass effect on the plastic.
Also, the designer can perform the whole layout in white or use white as one of the colors for printing on dark or black paper.
It is enough to inform the technologist about this – and we will tell the designer how to prepare the layout, we will offer the optimal solution – how best to print a white color.