Here is a recap of my experiences brewing Walnut Dye with Black Walnut Hull Powder rather than fresh Green Black Walnut Hulls.
I made five different Holsters and tried several different methods of dyeing and finishing. I finally got reasonably close to the results I was looking for. My main issue was uneven coloring and darkening in certain areas on a Holster. Dyeing a flat piece of leather produced good results. Dyeing a sewn item caused problems.
Attached are pictures of two Mexican Loop Holsters and a Belt. These were immersed in the Walnut Dye for 12 hours and finished per Ten Wolve’s procedures with one exception. I omitted the Lexol and Neets applications and went right to applying Skidmore's. So far this seemed to produce the best results with "Powder Brewed" Walnut Dyes.
My conclusions after all of this experimenting with "Powder Brewed" Walnut Dyes is that dye brewed with fresh Green Black Walnut Hulls probably works the best and is more forgiving. I do not recall having any big issues with uneven coloring or darkening with my previous batch of "fresh Green hull brewed" dye. Just speculating but that may be because when brewing with fresh hulls, the solution dissolves completely. The powder may not. I had to scoop out a lot of sediment after brewing with powder. The quality of hides does definitely make a difference. I cleaned everything with pure Lemon Juice before immersing. I also was able to go right to Skidmore's omitting the Lexol and Neet's application. This may not be the case with fresh Green hulls. I learned that it is only necessary to keep the Pistol in a wet Holster for one half hour to wet mold.
Finally, I would say that "Powder Brewed" dyes can be acceptable substitute for "fresh Green Hull Brewed" dyes but one must experiment and test to see what works the best. As soon as fresh Green Black Walnut Hulls are available again, I will brew up a batch.
Here is a link to a Tutorial I made about brewing Walnut Dye with Black Walnut Powder:
http://www.johnnymccrae.com/BREWING_WALNUT_DYES.html This Tutorial describes how I brew the dye with powder. If you decide to brew some Walnut Dye using Black Walnut Powder, please try a small batch first and do some testing on scrap leather.
Attached are pictures of the completed two Mexican Loop Holsters and the Belt. Also attached are pictures showing the darkening and uneven colors. Some Leather Workers may like the look of the darkening and uneven coloring.
Below is a note from Ten Wolves Five Shooter on brewing Walnut Dye with fresh Green Black Walnut Hulls.
Just a note on walnut hulls, TRY TO USE GREEN black walnut HULLS when making your dye, you will get much better results, problem is you can only get them once a year and usually the beginning of fall, if you have access to them, you can gather as much as you can and freeze them if you're not ready to cook your nuts at that time, later you can add the black walnut powder to your batch and this will only enrich your dye, some scummy looking stuff will form on your dye after a while, this doesn't hurt your dye, just scoop it up and remove it, your dye will last for years if you just add to it and take care of it, natural dyes are the best in my opinion, they are through and through and won't wear or rub off...