| 摘要 |
A chromene compound typically represented by the following formula, When placed in a state of developing color, the chromene compound exhibits absorption bands in two wavelength regions of 440 to 500 nm and 570 to 630 nm. A difference in the absorption intensity between the two absorption bands is small, and an intensity ratio in the color density in the two absorption bands is usually in a range of from 0.7 to 1.2. A color tone of a neutral tint such as grey or brown is obtained by using a single compound.
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