When a print isn’t coming out right, it’s easy to blame the ink.
Sometimes the ink really does need an adjustment. But just as often, the problem is the amount of ink on the press, roller height, impression, paper, temperature, or a combination of several things.
At Blue Press Ink (BPI), we work with letterpress and printmaking inks every day, and one of the most useful troubleshooting habits we’ve learned is simple:
Change one thing at a time.
If you change the ink, roller settings, packing, and impression all at once, you may get a better print—but you won’t know what actually fixed it.
Here are some of the most common ink and press problems we see and where we recommend starting.
1. The Print Looks Heavy, Blurry, or Filled In
Likely cause: Too much ink.
This is probably one of the most common letterpress printing problems, especially when you're trying to get better coverage.
Adding more ink can seem like the obvious solution when a print isn't solid enough, but too much ink can actually create additional problems. Fine details begin filling in, small type gets heavier, edges lose their sharpness, and drying time can increase considerably.
Before adding more ink, look at the ink film already on the rollers.
A good rule with letterpress is to start with less ink than you think you need and add gradually.
If you've already overloaded the press, removing some ink is usually better than trying to solve the problem with additional adjustments.
2. The Print Is Light or Doesn't Have Solid Coverage
This one is trickier because several different things can look almost identical on the printed sheet.
Possible causes include:
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Too little ink
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Incorrect roller height
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Insufficient or uneven impression/packing
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Uneven packing or makeready
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Ink that is too stiff
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Paper that doesn't readily accept the ink
Before adding ink, determine whether the problem appears consistently across the entire form.
If everything is printing evenly but simply too light, you may need a little more ink.
If only certain areas are light, adding ink to the entire press may make the properly printing areas too heavy. Check roller height, packing, impression, and makeready first.
3. Ink Is Too Stiff
Ink consistency changes with temperature.
An ink that runs beautifully in a warm shop may feel considerably stiffer on a cold morning. That's especially noticeable with heavier-bodied letterpress and relief inks.
Before modifying the ink, give it time to reach normal room temperature and work it thoroughly with an ink knife.
If the ink genuinely needs to be reduced, use an additive designed for the ink and add it in very small amounts. With BPI Gel Reducer, start around 1% by weight, mix thoroughly, and evaluate the ink before adding more.
It's much easier to add a little more reducer than to put the body back into an ink you've made too loose.
4. Ink Is Too Loose or Runny
The opposite problem can also occur.
Ink that is too loose may spread, fill fine detail, mist or sling more easily, or simply lack the body you want on press.
Temperature can again be a factor. Ink becomes softer as it gets warmer.
If temperature isn't the problem, magnesium carbonate can be used to stiffen and increase the body of an ink. Where additional body and tack are desired, Heavy Binding Varnish (HBV) may be appropriate.
Again, small additions are the key.
At BPI, we always recommend making controlled adjustments rather than dumping a large amount of additive into the ink at once.
5. The Ink Isn't Drying
Before reaching for drier, look at how much ink you're putting on the sheet.
A heavy ink film takes longer to dry.
That's an important distinction because adding drier won't necessarily correct the underlying problem if the press is simply carrying too much ink.
Other factors can include the ink formulation, paper, temperature, airflow, and the amount of ink coverage on the sheet. Non-absorbent and heavily coated stocks can also require more drying time than absorbent papers.
If the ink film is appropriate and you still need faster drying, a compatible drier can help. Follow the manufacturer's recommended starting percentage and don't assume that more drier automatically means better results. We recommend our 2-Way Drier used at 2-3%.
6. The Ink Is Drying Too Fast on the Press
Letterpress ink needs enough open time to remain workable on the press throughout a normal printing session. Ink that begins setting up on the rollers, disk, or distribution system can make printing frustrating and lead to inconsistent results.
This is something we specifically consider when formulating Blue Press Ink letterpress inks. BPI inks are designed to stay open on the press while still drying hard on the printed sheet. That balance gives printers plenty of working time without the ink quickly setting or skinning on rollers or the ink disk.
And if you're using BPI ink, you generally shouldn't need to add anything simply to keep it open during a normal press run. That's already built into the formulation.
7. Ink Coverage Is Uneven
Uneven coverage doesn't automatically mean the ink needs adjustment.
Check:
Roller height.
Are the rollers contacting the form correctly? Check the roller stripe with a roller-setting gauge rather than relying only on how the rollers look.
Roller condition.
Flat spots, glazing, contamination, or worn rollers can affect ink transfer.
Ink distribution.
Has the ink had enough time to distribute evenly?
Impression and packing.
Is the problem actually uneven pressure rather than uneven ink?
The form itself.
Large solids and fine type can present very different inking requirements.
If one portion of a form prints correctly and another doesn't, adding more ink everywhere is rarely the first thing we'd recommend.
8. Ink Is Picking or Pulling the Paper
If fibers are pulling from the sheet, the ink may have too much tack for that particular paper.
But paper itself can also be the culprit.
Some soft or loosely surfaced papers are much more susceptible to picking than others.
Before substantially modifying your ink, try another sheet and see whether the problem follows the ink or the paper.
That's another good troubleshooting principle:
When possible, isolate the variable.
9. Fine Detail Keeps Filling In
Start with ink quantity.
Too much ink is one of the first things to investigate when fine type, hairlines, or small counters begin closing up.
If reducing the ink doesn't solve it, check roller height and impression.
Excessive impression combined with too much ink can make a beautifully detailed plate look much heavier than intended.
Rollers set too low can over-ink the plate and contribute to filling fine detail and small counters.
The goal isn't to put as much ink as possible on the sheet.
It's to put the right amount of ink in the right place.
10. Don't Try to Fix Everything With an Additive
Reducers, body builders, driers, tack reducers, and other ink additives are useful tools.
But they're tools—not automatic solutions.
Before changing the ink, ask:
What am I actually trying to correct?
If the real problem is roller height, adding reducer won't fix it.
If you're carrying too much ink, adding drier may create a new problem without solving the original one.
If one area isn't printing because it needs makeready, adding more ink may simply over-ink everything else.
That's why at Blue Press Ink (BPI) we encourage printers to diagnose the problem before modifying the ink.
11. Ink Isn't Transferring Cleanly
Sometimes there appears to be plenty of ink on the form, but it isn't transferring cleanly to the sheet.
Possible causes include ink that is too stiff or tacky for the paper, incorrect roller settings, insufficient or uneven contact, paper surface characteristics, or shop temperature.
Before adding more ink, check whether the form itself is receiving an even ink film. If it is, but the ink isn't transferring cleanly to the paper, consider the relationship between ink tack, paper surface, and impression.
A softer or more absorbent sheet may behave very differently from a hard, smooth stock with exactly the same ink.
Again, make one change at a time so you can identify what actually improves the print.
A Simple BPI Troubleshooting Routine
When something isn't printing correctly, try this order:
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Look at the printed sheet. Is the problem everywhere or only in certain areas?
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Check the amount of ink. Too much ink causes more problems than many printers realize.
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Check roller height and ink distribution.
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Check impression, packing, and makeready.
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Consider the paper.
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Consider temperature and shop conditions.
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Only then decide whether the ink itself needs adjusting.
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If you make an adjustment, change one thing at a time.
That last step can save a lot of frustration.
Still Having Trouble?
Letterpress printing has a lot of variables, and sometimes a problem doesn't fit neatly into a troubleshooting chart.
If you're running Blue Press Ink and something doesn't seem right, contact us.
Tell us what ink you're using, what press you're running, what paper you're printing on, and what you're seeing on the sheet. A photo of the print can be especially helpful.
BPI isn't just here to sell you ink. We make ink, we formulate ink, and we're happy to help you figure out how to make it work on your press.
Made in Texas. Printed Everywhere.