What causes printmaking mistakes, and why it keeps happening

What to take away

• Most print faults fall into four families: mechanical, material, environmental and procedural. Naming the family narrows the search immediately.
• Change one variable at a time when diagnosing, exactly as you would when testing.
• The room is a variable. Temperature and humidity cause faults that get blamed on technique for years.
• Write the plan before the failure. A fault log is worth more than a good memory.

The four families

Mechanical. Pressure, packing, roller parallelism, a block that is not type high, a bed that has dished. These produce faults that are consistent across the sheet or consistent in one region.

Material. Ink too stiff or too soft, paper too hard or too absorbent, a sizing that repels, a block that has hardened. These produce faults that change when you change the material and nothing else.

Environmental. Humidity, temperature, drafts and light. These produce faults that come and go with the weather and drive people to blame themselves.

Procedural. Wrong sequence, wrong drying time, contamination between stages, no records. These produce faults that seem random until you write the sequence down.

The diagnostic order

1. Reprint with everything unchanged. Faults that vanish were procedural.
2. Change the paper only. Faults that vanish were material.
3. Change the ink film only, in one direction.
4. Check the mechanics: straight edge on the bed, packing thickness, block height.
5. Only then question the image itself.

Running this in order takes an hour and beats a week of adjusting three things at once.

The environment nobody checks

Paper is hygroscopic, so a room that swings between damp and dry changes the sheet between sessions. That shows up as cockling, uneven ink take-up, inconsistent registration and, over time, mold.

Institutions treat this as a measurable problem rather than a matter of taste. A paper published by the National Archives on the realistic preservation environment argues against the common assumption that environmental criteria are simply a compromise between the building, the occupants and the collection. The same argument applies to a print room: stability is a specification, not a leftover.

Buy a hygrometer, log the reading at the start of each session, and the environmental family of faults becomes visible within a month.

Write the plan before the failure

The habit that separates printers who improve from printers who repeat themselves is documentation. The National Archives sets out records emergency planning as documenting and managing risk factors, writing a plan, and training people in it before anything goes wrong, and the small version of that is a fault log kept at the bench.

Record the date, the fault, the family you assigned it to, what you changed, and whether it worked. Six months of that turns most recurring faults into a two-minute lookup.

Fault	Most likely family	First thing to check
Fill-in of fine lines	Material	Ink film thickness
Uneven band across the sheet	Mechanical	Roller parallelism
Cockled paper	Environmental	Room humidity
Ghost image on the next print	Procedural	Interleaving and drying
Patchy wash on a coated print	Procedural	Coating evenness and drying

Chemical processes add their own family, and our walkthrough of the cyanotype process covers the faults specific to exposure and washing. The room itself is covered in our list of workspace mistakes made at home.

Common questions

Why does the same fault come back after months? Because the cause was seasonal. Check your humidity log before assuming a technique regressed.

Should I keep failed prints? Yes, at least one of each fault, labeled. They become your reference set.

How many variables can I change at once? One. Every printer knows this and most ignore it under time pressure.

Is a fault ever just bad luck? Rarely. Randomness is usually an uncontrolled variable you have not identified yet.