When to use letterpress ink additives in your printing
Ideally you’ll be printing ink additive free. That said, when you’re facing challenges with your letterpress inks, some of our additives may help you out when used in moderation. But why is additive-free printing ideal? When you add an additive, you alter the chemistry of your letterpress ink and another problem may arise. Your ink has three characteristics: body, tack and oiliness. An additive that decreases your tackiness may, for instance, increase your oiliness. Always consider whether an additive is necessary. Know that sometimes it will be necessary. In these cases, use your additive of choice sparingly.
The problem: your ink skins. Let’s say you’re printing with oil-based inks and you have to step away and leave your project unfinished for a few hours. Uh oh. Oil-based inks harden and dry up, leaving a skin on your ink. This skin can damage rollers, makes for a tough clean up, and also makes printing difficult as small bits of skinned ink will be stuck on your rollers when you start running the job again.
The solution: Anti Skin Spray. Before you go off for a few hours, spray this additive lightly on your inked-up rollers and also on your mixing stone. When you resume printing, the anti-skin spray will dissipate into your ink and not affect your print job.
The problem: ink not drying on your paper stock. Say you’re printing on a paper stock that doesn’t dry easily. You notice your ink isn’t drying on the sheet in a reasonable amount of time.
The solution: three-way drier. This additive will help keep your sheets from offsetting (transferring still wet ink to the back of your sheets). Also good if you’re printing a huge solid area that might be slow to dry.
The problem: your ink is rubbing/scuffing off. Or your ink has a lot of trans white in it, its too fluid and the consistency is loose like sour cream. loose.
The solution: Aqua Flo Varnish. Aqua Flo Varnish can add firmness and ink body to your ink. Also, it adds a light varnish, which protects your ink by minimizing scuffing or rub off. It’s most commonly used with oil-based inks.
The problem: tacky ink. If you’re printing with oil-based inks over a large solid area and parts of the paper are transferring to your rollers, or paper fibers are sticking to your plate, your ink may be too tacky.
The solution: Tack Reducer.
The problem: you’re switching from a dark ink to a light ink. Before you print your light ink, you need to remove all traces of that dark ink from your rollers. In short, your rollers need a good deep cleaning.
The solution: Easy Street.
The problem: your ink is offsetting. This means you’re getting ink transfer from the printed front of an inked piece onto the back of the next piece. Or, perhaps you’re seeing scuffs or scratches in your inked areas.
The solution: High Gloss Overprint Varnish. This protective varnish provides a good barrier and resistance from scuffing.