Formulary's Weston's Amidol Paper Developer is one of the best in its class. Prints have neutal to cold tones with good crisp tonal separation and deep blacks. The working solution can be diluted to obtain softer results without greatly affecting the color. Bromide paper should be used with this developer for best results. The chemicals are used to prepare one stock solution. Solid amidol is added to make the working solution. Since amidol is very short-lived in solution, several packages are included in the kit. The stock solution has a shelf life of six months. When the amidol has been added the working solution is good for only 2-3 hours.