Candle light

If my plants are on there 12 hours of dark period will candle light mess up the cycle or is it just sun light and light bulbs that will?

yep, both produce light

the only way to check up on your girls during night cycle is with some sort of green light...im not sure exactly what it is but someone on this forum will
Peace idk about the candle light

during the flowering phase, the dark period should not be violated by normal light. It delays flower development due to hormones in the plant that react to light. If you must work on the plants during this time, allow only as much light as a pale moon can provide for less than 5 minutes.
A green light can be used to work on the garden during the dark period with no negative reactions from the plants. These are sold as nursery safety lights, but any green bulb should be alright. It's usually best to keep the dark hours when you would normally not wish to visit the garden, and vice versa.

Why candles?

thanks for the input.