A general purpose ready for use ink that produces a bright soft print on a knit T-shirt is apt to cover only one side of the loops in terry cloth and give a harsh hand on towels. This is because it is designed to stay on top in order to give bright colors with minimum deposit on a T-shirt instead of soaking in as printing on terry cloth requires in order to color both sides of the loop. An ink thin enough to penetrate a towel properly would not hold a sharp line on a T-shirt and might be inclined to wick. Special ready for use inks for towel printing are possible, but there is a limit to the percentage of pigment that can be incorporated without starting to affect the hand. For this reason it is a good idea to avoid intense blacks and fluorescent colors that require high loads of pigment. As a general rule a maximum pigment load of 4% is recommended when printing towels.
Ready for use inks vary so it is impossible to make a blanket statement that will apply to all. Generally speaking one must add water until adequate penetration is achieved. With the system I am familiar with, this means adding at least one part water to three parts ink and possibly as much as one part water to two parts ink. This will improve penetration and hand, but will result in a reduction in color brightness. If water alone does not provide proper penetration a penetrant can be added, but remember that too much can affect wash resistance and blue edges. Softeners are available but make sure the ink you are using does not already contain one before throwing more in.
Mixing Towel Inks From Components:
When making an ink for towels from components, use as little thickener as possible, keep the pigment level under 4%. Use the minimum amount of soft hand binder necessary, but not less than 6%, and if the hand of the resulting ink is still too harsh, add the maximum amount of softener additive possible with-out affecting wash resistance.
Softer Colors For A Softer Hand:
When pigmenting a prepared base, select a soft hand base to begin with, reduce with water as required and keep the pigment load under 4%. If you tell your supplier that the base will be used primarily for towel printing they might offer something other than their general- purpose base. The softest hand base my company offers is one designed primarily for printing multi-color flock transfers, and the only time it is mentioned for other uses is when soft hand is the customer’s primary interest.
Remember that you are coloring loops that can move by their own length in any direction. This eliminates fine lines from consideration because a fine line will disintegrate into a scattering of dots when the loops are disturbed. As a general rule, lines finer than three times the length of a loop must be avoided. Given loops 3.2mm (1/8th inch) long, lines finer than 9.5mm (3/8th inch) wide must be avoided.
Polyester meshes in the 30 to 43 threads/cm (77 to 110 threads/inch) range are recommended, as are hard bases and soft squeegees. Heavy squeegee pressure and a fast stroke are also generally recommended. Some printers actually prefer low tension screens and most think double stroking gives better penetration. Given variation in loop length, density, lay and absorbency, one cannot etch rules for printing in stone. Just keep in mind that the ink must penetrate enough to color the bottom of the loops and that towels should be soft and absorbent and adjust inks and print technique accordingly. Towel printers have told me that loose screens give best penetration.
A penetrant is a wetting agent that increases ink penetration into a substrate that is often used in flag or towel printing.