This can mean many things. I use it to paint mostly. I have used it to give a shine and a tough coat to a painting I have completed and I have added Ink, acrylic and pigment to the resin or used a combination.
I have made items using moulds and added to a painting, your imagination holds no boundaries.
My understanding so far is that it can be a Polymer (Total Cast) or Epoxy (Glasscoat) based, the first being less toxic.
I have used both and use Glasscoat the most.
I warn you that once you start, it is addictive and a whole lot of fun.
My take homes are, wear a mask, wear gloves protect everything, the floor the table, yourself. Baking paper is your friend as is talc powder if you wash your hands and can’t get it off your hands.
You have to get your bubbles out of your pour, so be careful not to set your painting alight.
Note to self, alcohol and torch dont mix. You might like to start using acetone lightly sprayed over your work to start, it does break the bubbles be careful not to use to much or it wont set the resin.
Last and not least, make sure you measure and mix if either are not accurate you will have problems setting your resin. Good Luck.