PENGARUH PAPARAN SINAR MATAHARI TERHADAP KUALITAS CETAKAN PADA TINTA ROTOGRAVURE GERANIUM DENGAN PENAMBAHAN ADITIF

Abstrak
Produk cetakan yang digunakan di luar ruangan sering mengalami permasalahan visual, terutama dalam bentuk perubahan gradasi warna akibat paparan sinar matahari secara berkelanjutan. Masalah ini biasanya disebabkan oleh tinta yang memiliki ketahanan cahaya (lightfastness) rendah, sehingga warna cepat pudar dan kualitas visual cetakan menurun. Tujuan dari penelitian ini adalah untuk mengetahui stabilitas warna hasil cetakan melalui pengukuran nilai ΔE, Lab*, dan density sebelum dan sesudah penyinaran dengan alat lightfastness chamber selama 0, 20, 40, dan 60 jam. Pengujian dilakukan di laboratorium QC/R&D PT Sakata Inx Indonesia. Hasil pengujian menunjukkan bahwa semakin lama durasi paparan sinar matahari, semakin besar nilai ΔE dan semakin menurun nilai density, yang berarti terjadi pemudaran warna. Tinta dengan aditif Anti UV dan Antioksidan mampu memperlambat pemudaran, namun tidak sebaik tinta Semi Lightfastness. Dengan demikian, penambahan aditif berperan penting dalam meningkatkan ketahanan tinta terhadap sinar UV, namun masih diperlukan pengembangan lebih lanjut untuk aplikasi luar ruangan yang tahan lama.
Kata kunci: Tinta, Lightfastness, ΔE, Density, Aditif

Abstract
Printed products used outdoors often experience visual issues, particularly in the form of color gradation changes due to continuous exposure to sunlight. This problem is generally caused by ink with low lightfastness, which leads to rapid color fading and a decline in overall visual print quality. The objective of this research is to evaluate the color stability of printed materials by measuring the ΔE value, Lab* coordinates, and density before and after exposure using a lightfastness chamber for 0, 20, 40, and 60 hours. The testing was conducted at the QC/R&D laboratory of PT Sakata Inx Indonesia. The results showed that the longer the exposure duration, the greater the ΔE value and the lower the density, indicating noticeable color fading. Inks with Anti-UV and Antioxidant additives were able to slow down the fading process; however, their performance was still inferior compared to Semi Lightfastness ink. Therefore, the addition of such additives plays an important role in improving ink resistance to UV radiation, although further development is still needed for long-lasting outdoor applications.
Keywords: Ink, Lightfastness, ΔE, Density, Additive