Asking for the paints and brushes in your example would be like asking for your copy of AutoCAD when you deliver the drawings. They are just the tools. It is interesting how everyone takes ownership of things. When you work for large companies they take ownership of every idea you have. In small companies such as yours they take ownership of what they were asked to produce. It still boils down to whoever paid for it should have written that into the contract. If they did not then it's yours. If they did then it's theirs. I have worked on it both ways. I do know that the largest engineering firm in Kansas City (I won't blister my mouth by saying their name) has dismissed contractors who do not give them the cad file. In fact, I believe every large engineering firm in Kansas City requires a copy of the cad file. On the other hand they will not give out one to the client unless it is in the contract to do so. I guess the contract rules all and if it isn't written out then it is up for agrument.