Dirt is large lumps of wet or soft soil which can be thrown up by the vehicles tracks or wheels or deposited by crewmen or by other activities around the vehicle. Dirt will accumulate differently between vehicle types, so it is best to study the vehicle you are making and note the areas of build-up. Crewmen tend to mount and dismount the vehicle in the same place, but again this will vary between vehicles, so some areas will be much dirtier than others. Dozer blades and earth anchors when used are forced in to the ground and therefore may have lumps of compacted soil stuck to them, particularly in recesses or corners. Dirt is best applied by dry brushing with a slightly wetter brush than normal, building up the effect gradually in the areas which are most affected. It is best to vary the colour or tone to achieve the look of wet (darker) and dry (lighter) dirt. I use at least three colours for dirt and Humbrol colours No’s 62, 72, 84 and 93 are a good starting point. These colours can be mixed with each other or with black and white for more variations. Plaster of Paris powder can also be mixed in with the paint to create a texture on the dirtiest areas. The powder can dry the paint out instantly, so you may need to add more paint to keep it useable. The mix will need to be noticeably wet and applied with a brush in a dabbing action. Only use this plaster mix sparingly and in small areas as it can look out of scale if you get carried away, particularly in 1/76 scale. Remember you can work back in to the dirt effect as described in the dust section. Adding dirt is a slow process, but keep checking your reference and it will be well worth it in the end. One other thing I should mention before leaving dust and dirt, is weathering tyres. Dust will stick to the tyre walls and the surface of the tread when the dust is light. When dust is in heavier concentrations, it will be force in to the bottom of the tyre tread as well. Dust can be applied to your models tyres by dry brushing them all over, but still let some of the original tyre colour show through. By using a wash of your dust colour on the surface of the tyre, it will give the effect of dust being caught in the treads. Dirt is usually darker in colour than dust, and can be quite opaque if fresh. Mud and dirt will always get in to the bottom of the tread and up the tyre walls. Dry brush the tyre walls and then paint the tyre tread with a darker colour than your dry brushing. When the tread is covered, wipe the paint off, leaving some paint in the recesses of the tyre. This will give the effect of a tyre with a light covering of dry dirt on the walls, and wet mud stuck between the treads. The surface of the tyre which has come in to contact with the road will look cleaner where the dirt or dust has been worn away and can reveal original colour of the tyre.

Land Rover 90 “Wolf’ has been through a muddy puddle that has covered the bonnet. Note the driver has then cleaned the lights and number plate. May 1998
Light dust has stuck to the tyre walls and the surface of the tread on this Land Rover Ambulance. Wet mud has been thrown up on to the bodywork and dried with a heavily textured appearance. May 2006

This Warrior MAOV with tracks and roadwheels covered in mud has obviously not been at the head of the convoy and has been showered with track spray. April 1998
A Challenger 1 with mud clinging to the track and road wheels indicating the wet ground conditions. April 1998
This Chieftain has wet mud across the lower hull and around all the running gear. This has started to dry on the bazooka plates with a distinct colour difference between wet and dry mud. April 1995
Wet mud is spread across the surface and into the tread of the tyres of this Stalwart. October 1988
This CET is a good example of the way damp soil clings to shovels, dozers or earth anchors. April 1998
Copyright Tim Neate