Color

Colorimetric environment

As a general rule, keep the same color environment for all colors of your document; ideally, you should use the same color environment your images have.

You should avoid mixing RGB colors with CMYK or spot colors, as good practice.

Spot colors

It is perfectly OK to use spot colors (or Pantone) in files prepared for Wedia. If you use spot colors, don’t forget to configure the knock-out / overprint parameters, to ensure your PDF created from the platform will be displayed correctly when it will be given to the printer (read next paragraph).

Knock-out/Overprint

As said in the previous paragraph, give special care to the knock-out / overprint when you use other colors than RGB or CMYK (for example, a 5th color which could be a spot color, a varnish, a metallic PANTONE®…).

To simplify, there are two methods:

• overprint: It means objets are printed one above the other, in the same order they are displayed on the screen.

• knock-out: It means, where an object is placed, the other colors are not printed. So there is no overprint.

Here is an example: a text frame is placed above a tint area.

Open

If the text frame is in overprint, here is what we will see when we hide the black coat:

Open

The tint area is not changed : the text frame will be printed over it, which could sometimes cause unintentional transparency effects, like the following one:

Now, here is the case when the text frame is knocked out. Hiding the black coat, the tint area will look like this:

At the intersection of the text frame and the tint area you can see the color has been knocked out, meaning it won’t be printed to prevent any transparency result when printed.

This parameter is essential to create self-sufficient documents when you are using spot colors. You have to choose the best solution to use; we recommend to contact your printer to define the right parameters to apply, depending on the ink and the paper you will use.

Handle the knock-out

• for the texts: in your paragraph style, in the section Character Color, you will find two check-boxes to check to command the fill and stroke overprint.

• for vectorial frames: the knock-out is handled in the object style, in the sections Fill and Stroke.

Convention in naming colors or gradients

When you create a new swatch of color or of gradient, you must name it respecting the following instructions:

• never use accented characters

• never use special characters

• never use the symbols "<" or ">"

• never insert spaces (" "); replace them with underscores ("_")

• never start a name with a number

• make a preference for lowercase

Tint areas

In tint areas frames, you can use tints below 100%. But for texts paragraph and tables, you must create a specific style and proceed to validation tests before.

Opacity (transparency ALPHA) and transparency effects

When you create a color swatch, a gradient swatch or an object, you can apply transparency effect, whatever your desktop-publishing software is:

• opacity level

• linear gradient from 100% tint to full transparency

• mix of transparency, like Photoshop®. ones

You can use them on tint area frames. But they are not supported on text frames; for the cells fill in a table: the opacity effects must be configured in the cell styles (InDesign only).

Registration color

In the swatch palette of any desktop-publishing software you will find the color named Registration. This is a specific color made of:

• 100% of Cyan

• 100% of Magenta

• 100% of Yellow

• 100% of Black

This swatch is used to trace print and crop marks, displayed on all printer plates.

Rich Black

Whatever your layout is, we recommend you to create a rich black swatch: the default black swatch only has 100% of black (no other color), which can cause transparency effects due to overprint.

For the safety of your document and prevent any trouble, we recommend to create a rich black:

• either with 60% of Cyan and 30% of Yellow in addition to the 100% of black, if you want a "cold" black (dominance of blue)

• or with 60% of Magenta and 30% of Yellow in addition to the 100% of black, if you want a "warm" black (dominance of red)

You will then have a swatch with a powerful ink covering. Such rich black must be reserved for tint areas only. It musn’t be applied on texts, as it could cause registration issues for the printer.

Clear unused swatches

Once you have finished your layout, we recommend you to delete all unused swatches. This cleaning comes in line with the fact you are preparing your file meticulously for the platform.

In Adobe InDesign, you have a special command in the palette Swatches which will select all color unused, like this: