Home made PCB:ferric chloride concentration

I want to use ferric chloriode as an etchent for a home made PCB
Can some one plz tell me what should be the concentration of the solution
i mean weight of ferric chloride in grams and the volume of water in liters

I have ferric chloride in powder form

I find that the concentration is not absolutely critical - If it does not come with instructions, then I would say roughly 3 or 4 heaped tablespoons per litre. If you find it does not etch fast enough (assuming you have warmed the water), then add a bit more.

It is also a Good Idea to add a Few Drops of Muriatic Acid (Hydrochloric Acid) to each ounce of the Ferric Chloride Solution.