耐光性通常使用作为光源的耐晒牢度试验仪来进行试验。这种耐晒牢度试验仪的曝光时间与暴露在自然光下的天数的比例如图5所示。对于金属印刷油墨要求在包装容器经耐晒牢度试验仪48小时曝光（约等于夏季自然光20天的量），无变色、褪色现象。如表6所示，酞青系蓝颜料耐光性十分安定，但黄以及赤到红系的偶氮颜料有耐光性不安定的特点，与其他的色相相比耐光性要差，稀释变浅色后更进一步显示恶化的倾向。
通过光对于颜料的构造变化起到什么样额作用现在依然有许多不明点，没有详细的报告，但一般通过光（紫外线）发生氧化还原反应引起的颜料互变异性体和sis－trans异性体的结构变化、光的吸收的变化发生变色、褪色。
黄以及赤到红系统的油墨中，在对配合使用及户外曝光等耐光性要求较高的场合有必要使用耐性颜料来制造油墨。
金属印刷油墨除了油墨本身的烘烤外，还有底漆烘烤过程中的加热，因此设计油墨时需要考虑到在这种烘烤条件下不发生变色、褪色的问题。但是，在后工程中会遇到制罐时的ハンダ热及溶接罐的补修涂料的的烧付等印刷物部分或全部受到高温加热的情况。与耐光性相同，是由颜料引起的，但未必与耐光性有相同的倾向，使用单（双）偶氮黄的黄系油墨有着较弱的倾向。在高温下的耐热性比起加热时间，温度的升高带来的劣化倾向更大，稀释率越高变褪色程度越大。
这种变褪色的原因有以下几个可能：
⑴.颜料本身遇热分解。
⑵.颜料向底漆层移动，或是直接向空气中飞散。
白颜料虽然本身有着很强的耐热性，但需要注意树脂成分加热后引起的黄变。
作为受热问题，除了变褪色外还有热迁移的问题。这是因为油墨涂膜中的颜料在受到一定温度以上加热的情况下，印刷油墨与底漆等上层部的涂膜发生移动的现象。使用耐热性差的黄系颜料的油墨很容易发生这种现象。
从印刷物角度来看，这种现象表现为油墨浓度的上升，从网点印刷的角度来看，表现为网点面积扩大。主要发生在黄系油墨中，需要与树脂受热引起黄变的现象区别对待。
这种现象当然是由使用颜料的耐热性所引起的，但According to底漆的树脂组成，需要系统性的确认。
Metal printed cans that provide packaging containers that are retort-processed after filling according to the contents. The conditions of cooking treatment vary according to the content. Food cans for fish and meat are usually heated at 115°C to 121°C for 60-120 minutes, and beverage cans such as coffee tend to be heated at high temperature for a short time, generally at 125°C Heat to 130°C for 30-60 minutes. Accidents caused by cooking treatment are as follows:
①. Blistering
Blistering refers to a phenomenon in which small bubbles are generated in the coating film after retort treatment. The reason is caused by the use of water-soluble components such as inorganic salts in the pigment as impurities. Commonly occurs in the case of insufficient washing of water-soluble substances in the pigment manufacturing process.
②.White, water spots
The phenomenon of whitening of the coating film is mainly caused by the pigment, but it is also related to the degree of hardening of the coating film itself, and the main reason is the conditions such as insufficient coating or baking conditions.
In the case of equipment for continuous retort processing, contact between can bodies is likely to occur, and whitening occurs only in this part.
③.Fade
Discoloration and fading caused by cooking treatment will occur when the ink using soluble azo pigments is diluted to less than 10%. This is directly related to the tolerance of the pigment, and the tolerance table of the ink is selected by referring to the above table.
④ Cooking displacement
During the cooking process, when the outer surfaces of the cans are in contact with each other, the pigment on the printed surface migrates to the outer surface of other cans through the primer, resulting in coloring. This may be because the pressurized water vapor enters the ink through the primer, contacts the pigment and travels to the coating film of other tanks. The above-mentioned discoloration and fading are also easy to occur in soluble azo pigments.
吕仕铭 杜长森 周华 - 《《涂料用颜料与填料》》