Drying marks and squeegee lines on prints

Owned by Lab: washing, drying, flattening and mounting the print, which owns the squeegee, the wetting-agent dilution and the drying method, and whose own troubleshooting table gives the same two-way split this entry does — a wetting agent at the wrong strength, or a print not squeegeed at all, with ILFORD naming both errors for the one fault. Three labs across Parts XVIII and XIX name this entry beside a single instruction, which is to squeegee everything or nothing, identically, and to write down which. This entry was written earlier from the negative-side drying faults and Part XII’s washing chemistry.

What you see

Straight lines, in the direction the blade travelled, or tide marks with a soft edge where a wet area met a drier one, or spots where individual drops sat and dried. On a glossy resin-coated print they are differences in sheen as much as in density, so they appear and disappear as you tilt the sheet.

They are almost always in the light tones, because that is where a small change is visible, and they are always on the surface rather than in the image.

Likely causes

1. A blade with a nick, or grit under it. A single hard particle draws a line the length of the print.
2. Wiping a print that is not clean. A squeegee spreads whatever is on the surface; if the wash left residue, the blade distributes it in stripes.
3. Uneven drying. A boundary between a wet area and a drying one dries at different rates, and a mark forms at the boundary.
4. Hard water. Tap water carries dissolved calcium and magnesium salts, and a drop that evaporates leaves what it was carrying behind.

What is happening: the chemistry and physics

Three different mechanisms produce three similar-looking marks, and separating them is most of the value of this entry.

A mechanical mark is damage. A softened gelatin surface is easily scratched, and a blade dragging a particle across it leaves a groove that shows as a change of sheen. The layer is at its most vulnerable immediately after washing, which is exactly when the squeegee is used.

A deposit is chemistry. Water that evaporates leaves its solutes, so a drop that dries in place leaves a ring of whatever the water and the print were carrying — dissolved salts from the supply, and any residual processing chemistry that the wash did not remove. Part XII owns the washing argument, and its conclusion applies directly: what is not washed out is still there when the water goes.

A drying differential is physical. Gelatin shrinks as it dries and its optical properties change with it — which is the same mechanism Part XIII gives for dry-down: the wet layer has a refractive index close to water’s and returns light differently from the same layer dried and collapsed. A layer that dried at two different rates in two places has two slightly different final states.

!The confirming test: re-wet it

Soak the dried print in clean water for a few minutes and look at it wet.

• The mark disappears wet and returns dry: it is a drying differential or a surface deposit, both of which are potentially removable.
• The mark is still there wet: it is physical damage to the emulsion, and it is permanent.

Then separate deposit from differential. Wash the re-wetted print in distilled or deionised water, dry it without a squeegee on a rack, and look again. A deposit washes away and does not come back; a differential that came from uneven drying does not return if the second drying is even.

And check the blade. Run it along a clean wet sheet of glass with a torch behind: a nick shows as a line, and grit shows as one that moves.

Diagnostic questions

• Are the marks parallel and straight? Then they follow a tool, and the tool is where to look.
• Do they follow the shape of a drop, or of a raised edge? Then they follow the water.
• What is the water like where you live? A hard supply leaves more, and the final rinse is where it matters.
• Was a wetting agent used, and at what dilution? Both Kodak and ILFORD supply one to promote even draining; too much leaves its own residue.
• How was the print dried? Kodak’s own instruction for toned fibre prints is to dry them slowly, between blotters or on a rack, and to set a dryer to its lowest speed and temperature.

Corrective action

Re-wash in clean water and re-dry without a squeegee if the re-wetting test says the mark is not damage. A final rinse in distilled or deionised water is the cheapest single improvement available.

Replace or dress the blade if the test says it is mechanical, and inspect it before every session — the fault costs nothing to prevent and cannot be repaired after the fact.

Do not attempt to polish a scratch out of an emulsion. The layer is thin, and the second attempt is worse than the first.

Prevention

Rinse finally in distilled or deionised water, particularly in a hard-water area.

Drain rather than wipe wherever the paper allows it. Kodak’s instruction for resin-coated prints is to remove excess water from the surface and air-dry; for fibre prints it is to dry slowly between blotters or on a rack.

Dry evenly and slowly. Kodak add a reason of their own for the lowest dryer settings: drying with heat causes a shift to a cooler tone with some paper and toner combinations, so an aggressive dryer costs image colour as well as evenness.

Keep the wetting agent at its recommended dilution, since the remedy at double strength becomes the deposit.