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1994.pl

When Restoration Fails – A Case Study of Surface and Pigment Damage on the 1926 Bank Polski 10 Zlotych

Poland 1926 10 Zlotych — over-restored example: surface and pigment loss visible across dark fields — Over-restored 1926 10 Zl regular watermark — surface and pigment loss after aggressive cleaning.

This technical note compares three observable conditions on Bank Polski 10 Zlotych (1926 design): a properly restored rare watermark example, an over-restored regular watermark with visible surface and pigment loss, and unaltered reference pieces. The goal is diagnostic — to show how treatment affects ink, paper surface, and watermark presentation, without speculating on exact chemicals or methods.

Poland 1926 10 Zlotych, regular '10 zl' watermark — over-restored; pigment lift and matte surface in dark fields — (A) 1926 regular watermark — over-restored. Note the chalky, matte areas where darker inks lost binder; intaglio relief largely flattened.

Poland 1926 10 Zlotych, rare '992–1025' watermark — professionally restored; intact ink texture and balanced tonality — (B) 1926 rare 992–1025 watermark — properly restored. Inks retain gloss and ridge; tonality remains continuous across dark midtones.

Poland 1929 10 Zlotych, regular watermark — PMG 67 EPQ reference for original color and finish — (C) Reference: 1929 issue, regular watermark — PMG 67 EPQ. Baseline for unaltered color depth, ink sheen, and paper surface.

Poland 1926 10 Zlotych remainder — graded reference for plate and ink comparison — Reference remainder (graded). Control for plate detail and ink edges under magnification.

Diagnostic checklist: restoration vs over-restoration

Ink surface: proper restoration preserves intaglio ridge and subtle gloss; over-restoration yields matte, powdery areas and bald patches.
Tonal continuity: mid-dark fields should grade smoothly; chemical stripping creates uneven, speckled lightening.
Paper feel: natural stiffness has spring; re-sized or over-pressed paper feels board-stiff with dead snap.
Watermark clarity: gentle washing does not sharpen watermarks; harsh baths do not improve them and may disturb fibers.
Edge behavior: original edges show micro-burr; heavy pressing rounds or burnishes them unnaturally.

Takeaway. Correct conservation can stabilize and present a historic note without sacrificing ink or paper character. Over-restoration permanently removes pigment binders and flattens relief, leaving a piece that looks cleaner but reads wrong under light. Use graded originals as controls when assessing treated notes.

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