Fe-based pigments have attracted much interest owing to their eco-friendliness. In particular, the color of nanosized pigments can be tuned by controlling their size and morphology. This study reports on the effect of length on the coloration of β-FeOOH pigments prepared using an NH4OH solution. First, rod-type β-FeOOH is prepared by the hydrolysis of FeCl3·6H2O and NH4OH. When the amount of NH4OH is increased, the length of the rods decreases. Thus, the length of the nanorods can be adjusted from 10 nm to 300 nm. The color of β-FeOOH changes from orangered to yellow depending on the length of β-FeOOH. The color and phase structure of β-FeOOH is characterized by UVvis spectroscopy, CIE Lab color parameter measurements, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and powder X-ray diffraction (XRD).

Abstract
 1. 서 론
 2. 실험방법
 3. 결과 및 고찰
 4. 결 론
 References

• 유 리(한국세라믹기술원 엔지니어링세라믹센터) | Ri Yu (Engineering Ceramic Center, Korea Institute of Ceramic Engineering and Technology)
• 김일주(카이스트 부설 한국과학영재학교 화학생물학부) | IllJoo Kim (Department of Chemistry and Biology, Korea Science Academy of KAIST)
• 윤지연(한국세라믹기술원 엔지니어링세라믹센터) | JiYeon Yun (Engineering Ceramic Center, Korea Institute of Ceramic Engineering and Technology)
• 최은영(카이스트 부설 한국과학영재학교 화학생물학부) | Eun-Young Choi (Department of Chemistry and Biology, Korea Science Academy of KAIST)
• 피재환(한국세라믹기술원 도자세라믹센터) | Jae-Hwan Pee (Ceramic Ware Center, Korea Institute of Ceramic Engineering and Technology)
• 김유진(한국세라믹기술원 엔지니어링세라믹센터) | YooJin Kim (Engineering Ceramic Center, Korea Institute of Ceramic Engineering and Technology) Corresponding Author