Frilling

Lifted from Break/Fix — emulsion coating defects, entry 6 of twelve, with the swelling mechanism from diffusion, swelling and the journey into the emulsion.

What you see

The layer lifts, rolls back or detaches at the edges during processing. On a hand-coated paper the sequence is often bubbling first, then frilling at the edges, then the whole coat coming away in one piece.

On a plate it usually presents as a rolled edge, and the emulsion that has lifted is extremely susceptible to abrasion for as long as it is wet.

Likely causes

1. Adhesion failure at the interface. Contamination, no subbing layer, or an inadequately cleaned support.
2. Baths at different temperatures, or a bath run warm. Warm baths, long soaks and vigorous handling all make it worse.
3. A developer that swells the layer more than the one you are used to. This is a real and documented case rather than a hypothesis — see below.

What is happening: the chemistry and physics

Gelatin is a colloid that swells rather than dissolves in cold water, and Kodak’s 1928 primer records that the swelling is increased by a small quantity of acid or alkali and by warmth.

A swelling layer expands in every direction and the support does not, so the layer is in compression against a rigid surface. Where the bond is weaker than that stress, something has to give, and the edge goes first because it has a free face to move into. That is why frilling is an edge fault and not a general one.

Everything that raises the swelling — a warmer bath, a more alkaline developer, a longer soak — raises the stress. Everything that weakens the bond — grease, an unsubbed plate, a support the emulsion never properly wetted — lowers what the stress has to beat.

Diagnostic questions

• Did the plate clear evenly in the fixer? If yes, thickness is ruled out and the fault is at the interface — contamination, no sub, or a bath too warm. This is the discriminating test and it is free.
• What were the actual temperatures of the four baths? ILFORD’s published tolerances for film run from within 5 °C to within 1 °C depending on which sheet you read, and the course does not reconcile them - but both figures are tighter than most home benches achieve without checking.
• Did it start when you changed developer? A change of developer is the change most often overlooked because it is not a change to the emulsion.
• Is the lifted area at the edges, or in the field? A field fault is not adhesion.

⚗Why the fix is a hardening fixer and not a hardener in the emulsion

A working practitioner records developing a chloride paper in Selectol Soft after years of never having an emulsion lift — it bubbled, then frilled at the edges, then lifted clean off — and a hardening fixer prevented it completely. The rule that follows is hers: if your emulsion lifts, switch developers or use a hardening protocol, and the same remedy is given for plates as a hardening fixer in the second fixing tray.

The course’s default is no hardener in the emulsion, and the reasoning runs both ways. Unhardened emulsion tones more readily, spots more readily, and lets processing chemistry penetrate the thick uneven patches hand coating produces. Hardened emulsion resists penetration, especially by the fixer, so a thick patch fixes incompletely and darkens later in room light, after the print is finished and put away. Duffin says the same from the manufacturer’s side — excessive hardening interferes with developer penetration.

So the layer is hardened in the bath, where the dose is a soak time you can stop, rather than in the emulsion, where it is a decision made an hour before you knew you needed it.

Corrective action

Move the sheet to a hardening fixer — the F-5 acid hardening bath, or the F-53 stock made up as F-54a — or switch to a developer that swells the layer less.

Bring every bath to within a couple of degrees of the others before the next sheet goes in.

A sheet that has already frilled is not recoverable, and handling it wet will take the lifted emulsion off. Support it from below, do not squeegee it, and dry it flat.

Note the caution that travels with the remedy — prolonged immersion in a hardening bath at high temperature is itself harmful.

Prevention

Clean the support properly, and sub a plate that needs subbing.

Keep the baths matched. This is the single control both sides of the reticulation dispute agree on, and it prevents two faults at once.

Handle wet sheets by the corners and never squeegee them.

Reach for an acid hardening fixer before you reach for a hardener in the emulsion, because the first is a decision you can stop and the second is not.