DNA gel extraction trick
To cut the band in an agarose gel for dna extraccion, you need to visualize it first under UV light. And maybe you want to take a picture too.
Only a few seconds of UV light can damage and create new undesirable mutations in your dna. To avoid that and still have the picture of your gel, first cut the band as fast as you can under the UV light. Place the piece of gel where your band is in an eppendorf tube and then take a picture of the rest of the gel. Instead of your band there will be a hole, but still you will be able to tell where the band was, and keep it in your notebook for your records.
Another way of doing so is to forget about ethidium bromide and use a crystal violet agarose gel. But that’s a different story.