Mackie line

(photography) An adjacency or border effect created during development, at the border between areas of high and low densities.

Japanese Meaning

写真現像中、高濃度の領域と低濃度の領域の境界部分で発生する、隣接効果または境界効果を示す現象。 / 現像過程で、高密度部分と低密度部分の接触面に現れる、境界に起因する視覚的な効果。

When I developed the film, a distinct Mackie line appeared along the boundary between the dense and thin areas.

フィルムを現像したとき、濃い部分と薄い部分の境界に鮮明な現像境界効果が現れた。

Sense（1）

(photography) An adjacency or border effect created during development, at the border between areas of high and low densities.

Mackie lines

（ plural ）