Wax color depends on various factors: (1) raw material, (2) storage conditions, even… (3) bee race.
1. Color dependence from the raw material.
The wax melted from combs’ cappings is always of bright yellow color, but the older combs are always darker. Nothing to do with that.
2. Color dependence from storage conditions.
Please, note the following: Wax exposed to direct sunlight – gradually fades. Frozen wax gets covered with some whitish layer – this process is called “wax blooming”. However, after being warmed up to 40°C (either by placing to sunlight, or by pouring over with hot water, or by keeping close to some source of heat, or just simply by placing it into a hive), such a whitish layer instantly disappears! Please, do not worry, because the “wax blooming” – is a feature of its naturalness, this implies that a wax is pure and completely suitable for reuse.
3. Color dependence from the bee race.
Just to mention that wax color is very slightly dependent on the bee race.
Ref. 2. In no way it means that the “bloomed wax” has been deteriorated somehow. By placing into hive, such a pale “blooming” combs naturally warm up and the bees proceed to sew it successfully.
4. Color dependence from its processing.
Because of remelting process, when making foundation sheets, wax gets more lighter. It is expected to be that way. The reason: all the dark deposits and sediments contained therein – dust, propolis, pollen are allowed to settle down and finally removed away.