David,
If all you want is to contrast the hard and soft layers of maple,or just change the color, then dye is great. It will develop the color differences pretty distinctly, and you can pick your color choice.
However, that is only part of what the ferric acid treatment does (ferric nitrate or ferric acetate). The acid reacts with the sugars in the wood and carbonizes them......basicly turn the sugar to caramel. Then the heat is applied to speed up the reaction and finish the carbonization. The wood will look ruined, but when sanded/steel wooled down the dark and chatoyant 3-D distinction will show. This can not be obtained with dye.
Stacy,
I'm curious where you've gotten your information. Caramelized sugar is burnt sugar. Sugars are heated to 300-350 degrees until the begin to burn. I've never soaked my onions in ferric nitrate to caramelize them! Are you saying that the acidic compound you've created burns the sugars in the wood? A quick google search indicates that long before commercial wood stains were made in the late 19th and early 20th centuries furniture makers would dissolve iron nails in the acid until the acid was depleted and wouldn't dissolve any more iron, then used it as a brown stain for furniture.
How do you account for the chatoyant 3-D distinction on wood that has no ferric acid treatment? The chatoyancy in curly maple and other woods is caused by the way the fibers in the wood grow and how the light enters and is reflected back out. If the wood exhibits any chatoyance it's not because of any staining or chemical process. In fact, chatoyance is much more likely shown in woods like curly maple, koa, and walnut by the type of finish used and how it's applied. Chatoyance shows up by "wetting" the wood. Spit on it or dip it in a bucket of water and it will show without any chemical reactions. If you properly apply a penetrating finish the chatoyant shift of the curls as you change the angle of the wood to the light shows on natural unstained maple. I get this same thing on curly koa, curly and crotch cut walnut, and some other woods, and I don't add any stain, acids etc. It also shows up well on stabilized woods with curl and other figure, including stabilized un-dyed curly maple, koa, etc. All any colorant, whether yours or mine, does for chatoyance is increase the contrast.
In addition to the wetting action showing chatoyance, there are woods that never get a stain and finish and display chatoyance. Ironwood is a good example. The chatoyance is in the wood, and the polishing helps it show more with no chemicals added.
Every knife handle I've made with curly maple has been stained with modern dyes or furniture stains. They all exhibit good chatoyance because a. it's already a part of the wood, and b. I "wet" the wood with many coats of a penetrating finish, either tung oil or a polyurethane formulated for rubbing (which is a much better finish than any old style varnish).
If these old home brew things were really that good, safe, efficient, etc, then they would still be widely used, but they are not. Back in the day when this was how furniture was made, they'd also brush on varnish made from pine tree sap, and of course that never holds up well! You can get the same effect with modern materials and do it without all the hassle and possible danger, and it will likely last much longer.
David