Reading a test print

A test print is only useful if you can say what the marks on it mean. This guide goes fault by fault: what each one looks like on the test sheet, what causes it on inkjets and on lasers, which download isolates it, and what to try first before spending money on parts or ink. The short version lives on the test page itself; this is the long one.

Print the sheet or the PDF version at 100% scale before reading on. Every fault below is easier to name on a page whose contents you know in advance, which is the whole point of a test page: on a photo you cannot tell a printer fault from a fact about the photo.

Streaking: white lines along the print direction

Thin white lines that run in the direction the paper moved, cutting through solid blocks and text alike. On an inkjet this is almost always clogged nozzles: one or more channels are not firing, so a stripe of paper gets no ink. On a laser it is usually a scratch or a worn spot on the drum, or toner starvation along one track.

Run the nozzle check first. If a channel prints gaps in its pattern, run the printer's own head clean once or twice and check again. Two cleans that change nothing usually mean dried ink from long idleness; a third clean rarely helps, but letting the printer sit for an hour after a clean sometimes does. On a laser, inspect the drum for a visible line and reseat the cartridge before replacing anything.

If the pattern still shows gaps after two cleans and an hour's rest, the cartridge or tank on that channel is usually spent, and the per channel pages will show which one. When it comes to that, replacement ink on Amazon is a plain store link, not an affiliate link; if that ever changes, this page will say so.

Banding: repeating light and dark bands across the page

Horizontal bands at a regular spacing, visible in the color ramps as steps where there should be a smooth run. The regularity is the clue: a fixed period points at the paper feed advancing a slightly wrong distance each step, or at a print head passing over the same row twice at the band spacing. Starved ink produces banding too, but irregular and paler toward one edge.

The ramps on the test sheet make the period measurable: count bands per 100 mm against the scale bar. If the period matches the printer's feed step, look for paper dust on the feed rollers and run the feed calibration in the printer's own maintenance menu. If the bands fade as the page goes on, weigh the cartridge or check the tank: that is supply, not mechanics.

Ghosting: a faint repeat of the image, offset

Text or bars appear again, paler, a fixed distance from the original. On a laser the offset distance is the circumference of a roller, usually the drum or the fuser: the first pass leaves residual charge or toner and the next rotation prints it again. On an inkjet a much smaller offset comes from head timing, and the alignment page shows it as doubled verticals.

Measure the offset against the sheet's scale bar. A laser offset of 75 to 95 mm points at the drum; run several pages, and if the ghost fades with each one it was residual charge and may clear on its own. A constant ghost means the drum or fuser is wearing out. On an inkjet, run the printer's alignment routine and reprint the alignment PDF to confirm it took.

Color casts: grays that lean toward a color

The grayscale row and the gray patches on the sheet should read neutral. If they lean magenta, green or blue, one channel is printing weak or one cartridge is mislabeled or clogged. The per channel pages settle which: print cyan, magenta and yellow one page each and compare their strength. The weak channel is the one whose page prints pale or patchy.

A cast that appears only in photos but not on the test sheet is a color management problem in the file or the driver, not the printer. That distinction alone saves most of the money people spend on ink chasing a software fault.

Fading: the whole page prints light

Uniform paleness across everything, with no structure to it. Ink or toner is low, the density setting has been turned down, or draft mode is on. Check the driver's quality setting first: draft mode produces exactly this and is switched on more often than anyone remembers doing it. On a laser, take the cartridge out and rock it gently side to side; if the next page prints darker, toner is low and was sitting unevenly.

Spots, dots and smears

Repeating spots at a fixed spacing on a laser point at damage on a roller: measure the spacing to identify which one, as with ghosting. Random specks on an inkjet are usually ink mist or a dirty encoder strip; smears that follow the paper's leading edge come from ink that has not dried before the paper hits the output tray, or from a dirty platen after a borderless print.

Wrong scale: the ruler does not measure true

The sheet carries a 100 mm bar and a 150 mm ruler precisely so this fault cannot hide. If your print of the bar does not measure 100 mm, the print dialog scaled the page: look for "fit to page" or "shrink to printable area" and set scale to 100%. Nothing inside a printer changes geometry by a few percent; scaling faults are always in the software path. The methodology page explains how the PDFs pin their geometry so a correct print is exact.

Blank pages

A printer that feeds paper and prints nothing at all is usually not out of ink on every channel at once. On an inkjet, a fully blocked head or a protective tape left on a new cartridge are the common causes. From a phone, a blank page often means the app printed a blank second sheet rather than a fault at all. The solid black page is the fastest check: it either prints or it does not, with nothing subtle to misread.

When the printer is innocent

Faults that vanish on the test sheet but persist in your document are facts about the document: a low resolution image, a color profile mismatch, or a PDF rendered by a broken viewer. Faults that appear on plain paper but not on photo paper, or the reverse, are paper choice interacting with ink load. And any fault that appears only at one quality setting lives in the driver. The test sheet's job is to be the known quantity that makes those separations possible.

The order that wastes the least

Cheapest first: print the sheet, name the fault here, then run the one matching diagnostic rather than all of them. Nozzle check before head clean, head clean before alignment, alignment before any part is replaced, and the per channel pages before any cartridge is bought on suspicion. Most bad prints are one clean or one settings change away from good, and the expensive fix is only right when the cheap ones have visibly failed on the page in your hand.