Distressed inks stay wet longer than ordinary inks, which enables you to work the ink more easily, creating blending or shading effects. They will travel, or spread out, across the surface of your paper more than other inks, especially when sprayed with a little water, meaning that you can create smooth effects, rather than the lines or marks that are hard to avoid with quicker drying ink. They also have greater color stability when wet, so there is no breaking down or streaking of the color you are applying.
The ink is usually supplied in one of two ways. It either comes in a small jar, complete with a dropper for applying it to the paper, or on specialized pads. It can be applied with stamps, with specialist tools like stippling brushes and cut and dry foam pads, or by using artists' paintbrushes. Water is often added to the ink to make it spread out more than it naturally would.
Distress inks can be used to age the look of card or to antiquate paper. Special effects can be added to black and white photographs, either new ones or vintage ones. A tinting can be added to the background, maybe a sepia effect, and shading or color added with ink where desired. Then the edges are inked to further give the impression of aging. The slow drying nature of the inks also make them very suitable for embossing.
When aging the look of paper it should first be crumpled, taking care not to split or tear it. Inks can then be added and spread across the surface, using water to make the ink travel better. Spread the ink from the center to the edges. You may want to heat dry the paper to prevent too much ink moving to the edge. The look of card can be aged with edging tools to roughen them up and by spreading ink around the edges of the card using a stippling brush or foam pad to blend the color into the rest of the card.