A feature which is strangely absent from Adobe Illustrator (yet present in Adobe InDesign) is mixed inks. This gives the user the ability to make a new swatch based on percentiles of other swatches that can include spot colors, along with process colors.
InDesign’s mixed ink feature also allows groups of mixed ink colors to be made, based on how much of each ink should be in each swatch, and the increments they should differ by.
For pure spot color work, this can create colors that would otherwise require using blend modes such as multiply or darken to create similar colors. However, from a prepress standpoint, mixed inks have several advantages over applying blend modes to objects to achieve the same effect.
Embellishments
For digital devices that can apply inline varnishes, mixed inks make sense. In the following example, the headline requires a varnish
Usual way of doing this would be to create a second layer with an identical headline, but set to a Varnish spot color on another layer, with either a transparency effect such as darken or multiply applied; or overprint turned on from the attributes menu.
That’s fine if the position of the artwork is final, but if the design is in a state of flux, that requires moving the varnish to be in the same position as the type.
A solution is to use InDesign’s mixed ink to create a new mixed ink swatch. In this case, I’ll call it Varnished Headline, and give it 100% of the black and 100% of the varnish spot
This solution also applies to other common embellishments such as embosses, foils, raised varnishes, etc.
White Masks
When preparing label artwork for clear or metallic substrates, white masks have to be prepared so that the color art can appear correctly above the substrate. Take for example this logo to be printed over a silver background.
Again, by using mixed inks, it is possible to make a white mask that doesn’t require another layer, blend mode, and can move with the artwork. In this example, three colors would be created: the white mask; Red and a white mask; and Black and a white mask – the last two being mixed inks.
The art can then be recolored so that the red now uses the red mixed ink; the black now uses the black mixed ink; and the paper now uses the white mask ink.
Notice that the gold cup does not contain a white mask – that is because the gold color – when printed on a silver stock – will appear more like a gold foil.
Double-Hit Prints
On one or two spot colour jobs that have large areas of solid ink coverage, occasionally the same colour will be applied twice on the press as to hide any mechanical ghosting from the printing process.
In the above example, one plate would be for the solid color, and a second – though stippled plate – would be for the undercolor to hide the mechanical ghosting. This color can be set up using InDesign’s mixed inks.
But this is missing from Illustrator!
Despite the mixed ink feature being available in Adobe InDesign, it is notably absent from Adobe Illustrator. This is frustrating as artwork that usually requires the three solutions above is often prepared as Adobe Illustrator artwork, requiring old-school solution of layers and blend modes.
If you feel that this missing feature deserves to be in Adobe Illustrator, make sure to let the Illustrator Uservoice know!