Just a quick pictorial editorial on the use of fumed silica to enhance the max black and improved contrast in printing.This has been found to improve most hand coated processes. Your mileage may vary. Here is 8 ounces of Fumed Silica. It's in a gallon jar and looks to be quite enough to last a lifetime. I got this from Amazon for about $20 including shipping. I would suggest getting a more manageable amount at Bostick and Sullivan. This is enough to last a lifetime as it takes very little to do the job.