Ghosting
Ghosting is a printing defect where a faint, unwanted "phantom" image or repeat of a design element appears in a solid area of print. It looks like a shadow or a watermark of text/images that shouldn't be there.
It can manifest in two main ways:
- Mechanical Ghosting: A faint repeat of an image appearing elsewhere on the same side of the sheet (often in a dark solid background)
- Chemical (Gas) Ghosting: A "phantom" image appearing on the reverse side of the sheet, usually seen as a difference in gloss or sheen rather than ink color
Consumers often describe it as:
- "A faint shadow of the text in the background"
- "Seeing the image repeated lightly"
- "A boxy outline in the dark ink"
- "Looks like a watermark"
Also Known As: Mechanical ghosting, chemical ghosting, gloss ghosting, gas ghosting, phantom image, roller repeat, ink starvation (a cause of mechanical ghosting).
In simple terms: the press ran out of ink momentarily, or drying gases trapped in the paper stack created a phantom image.
What causes ghosting?
Ghosting is usually caused by ink starvation on the rollers (mechanical) or chemical interactions during drying (chemical).
1) Ink Starvation / Mechanical Ghosting
This happens on the press when a layout requires a lot of ink quickly (e.g., a heavy solid bar next to a knockout box).
- The form rollers deposit ink onto the plate
- The "heavy" part of the image strips the ink off the roller
- If the roller doesn't replenish fast enough before it rotates back around, it leaves a "starved" (faint) impression of the previous image in the solid area
This is common when design elements line up perfectly with the circumference of the press rollers.
2) Chemical (Gas) Ghosting
This happens after printing, while the paper is drying in a stack.
- Inks dry by releasing volatile gases (oxidation)
- If a heavy image on one side of the sheet releases a lot of gas, it can chemically interact with the drying ink on the sheet facing it (or the reverse side)
- This changes the gloss or drying speed of the ink on the other side, creating a "phantom" image that is visible when you tilt the page
It is most common on matte or dull coated papers.
3) Poor layout design (imposition)
If a designer places a heavy ink coverage element in line with a very light element, it stresses the inking system. "Taking the ghost out" often requires changing the layout or rotating the sheet on the press.
How to identify ghosting in a book
What it looks like
Look for:
- Mechanical: A faint, lighter "negative" of a headline, box, or image appearing inside a solid color block on the same page
- Chemical: A shape that appears on the reverse side of a printed image, visible mostly as a change in sheen (gloss vs. matte) rather than color
- Repeats: The ghost image is usually a specific element (like a logo or title) repeated faintly nearby
Where it shows up most
- Large solid color backgrounds (especially dark blues, blacks, reds)
- Matte coated art book papers (chemical ghosting)
- Pages with heavy ink coverage on one side and a solid color on the back
Simple at-home checks
Check A: The "Same Side" Test (Mechanical)
Look at a solid dark area.
- Do you see a faint outline of a text box or image that exists elsewhere on that same page?
- If yes, that is mechanical ghosting (ink starvation)
Check B: The "Tilt" Test (Chemical)
Hold the page under a light and tilt it back and forth.
- Does a "phantom" image appear in the gloss/reflection of the paper, even if the ink color looks even?
- This is chemical/gas ghosting
Check C: The "See-Through" Check
Flip the page.
- If you are just seeing the image from the back because the paper is thin, that is Show-through (not ghosting)
- True ghosting is a printed defect, not just transparency
Common look-alikes (and how to separate them)
1) Show-through (Paper Opacity)
This is the most common confusion.
- Show-through: You see the back of the page because the paper is too thin
- Ghosting: The phantom image is actually chemically or mechanically stamped onto the surface you are looking at
2) Set-off (Offset)
Set-off is when wet ink from one sheet rubs off onto the back of the next sheet in the stack.
- Set-off: Looks like messy, unintended ink spots or mirrors
- Ghosting: Looks like a subtle variation in tone or gloss, often retaining detail
3) Doubling
Doubling is a vibration issue.
- Doubling: A second image appears immediately adjacent to the original (like slightly blurred vision)
- Ghosting: The repeat appears inches away (mechanical) or on the reverse side (chemical)
Impact on book quality and readability
Readability
- Minor: Usually does not affect text legibility
- Distraction: In illustrated books, ghosting in dark backgrounds can be very distracting and look "cheap"
Image quality
- Solids: Large areas of color look uneven or dirty
- Photos: Chemical ghosting can ruin the finish of a photo, creating weird matte/gloss patches on faces or skies
Perceived quality
Ghosting is often seen as a sign of:
- Poor press layout planning
- Rushing the drying process (chemical ghosting)
- Using sensitive papers without proper drying precautions
Industry standards and "acceptable tolerances"
Ghosting is generally considered a defect, but "acceptable" levels vary by paper type.
Usually acceptable
- Extremely faint chemical ghosting on matte paper (very hard to prevent entirely)
- Ghosting that is only visible at extreme angles under bright light
Usually not acceptable
- Mechanical ghosting that makes a solid background look two-toned
- Ghosting that obscures text or ruins a photo's focal point
- Any ghosting clearly visible in normal reading lighting
A useful rule of thumb: If you look at a solid black page and clearly see a faint white box "ghosted" into it from the headline above, it's a defect.
What you can do as a buyer
- Distinguish from Show-through: First, make sure you aren't just seeing through thin paper
- Report it: If the ghosting disrupts images or makes backgrounds look uneven
Helpful wording for support: "Pages show ghosting—a faint repeat of text/images is visible in the solid background areas." Or "There is chemical ghosting (uneven gloss) visible on the photo pages."