Which type of varnishes tend to yellow faster than alkyd varnishes?

Phenolic varnishes are known to yellow more quickly than alkyd varnishes due to their chemical composition. Phenolic resins, which are used in the formulation of these varnishes, are sensitive to UV light and environmental factors such as heat and moisture. Over time, exposure to these elements causes the resin to undergo changes, leading to a more pronounced yellowing effect.

In contrast, alkyd varnishes have a more stable chemical structure that is less susceptible to such rapid changes in color. They are designed to resist the effects of light and weathering for a longer period, making them more suitable for applications where color retention is important.

Understanding the composition and properties of different varnish types is crucial for selecting the right product for specific projects, especially when aesthetics and durability are key concerns.