Based on a formula from Alois Senefelder Trilobite Workshop Paste Tusche is a traditional lithographic drawing material designed to provide optimum reticulation in a broad range of applications on both stones and aluminum plates. Water is added to the can and the tusche is dissolved to the desired value, then poured into another container to prevent it from getting darker. It is applied with a brush in much the same way you would use watercolor; lay it down and leave it alone. It can be layered allowing multiple layers to show through and responds well to etches. Etch as you would a crayon drawing.
A note on the use of lithographic Tusche:
Lithographic tusche is a solid material that when mixed with water creates a suspension of tiny particles that as the water evaporates creates a lacey reticulated pattern unique to lithography. There are several ways to apply tusche that result in different values. Some experience is required to control the medium.
• A thin application of a dark mixture can produce lighter tones while a heavy application of a light wash can produce dark results.
• A wash can be "floated" into water on the plate to control its shape and provide a variation in the reticulation.
• Tusche should be laid down and then left alone to "do its own thing" rather than reworking it. Re-working a wash can destroy the reticulation effect.
• When layering, a light wash over a light wash will be more successful than darker layers.
• When etching, etch for the grease. It may look light but be very greasy and thus dark.
• A good approach would be to etch the wash as if it were crayon.
• Mixing the tusche with hot water speeds up the dissolving process.
• Allow the can to remain open after mixing until the surface has dried out. Closing moisture in the can may cause it to soften and become unusable.