FX15 offers noticeably enhanced acutance but, unlike many other acutance developers, does not compress the mid tones — an unfortunate effect of Buetler, FX1 and FX2.

Rather, it gives a complete range of tones from rich detailed shadows through to delicate smooth highlights and everything in between. All this is achieved while exhibiting fine sharp grain and clear edge effects and Mackie lines. This is far from the mushy grain of other fine-grain developers such as D23 and D76.

Mix chemicals in order.
Sodium sulfite anhydrous100grams
Sodium metabisulfite0.5grams
Sodium carbonate anhydrous1gram
Potassium bromide1.5grams
Water to make

This formula also lasts fairly well keeping 6 months or more in a tightly stoppered bottle.

FX15 can be used full strength (for a softer portraiture image of full delicate mid tones) or diluted 1:1–3 (for landscape work where shadows and highlights need a nice contrast). Used this way, well diluted, will offer an element of compensation to the highlights and subdue those bright skies keeping them within the printable range.

Note: 1:3 is the recommended dilution for T-Max and Delta films.