Any bright light source used to light a car will be reflected in the cars panels or other reflective parts of the car such as wheels or windows. Reflections of the flash or light source are called specular reflections, or highlights, and can be a common problem when shooting any highly reflective object such as a car. When the light source is very large, such as a clear sky after sunset or before sunrise, then the reflection in the car is broad and relatively smooth or even. When the light source is small, such as the sun or flash (with or without modifiers, soft boxes etc), then the reflection of the light source in the car will potentially be distracting or unwanted.
 

This soft box was used to create a highlight in the chrome grille of this car. The grille was not prominent enough without the highlight from the strobe. In this case the highlight or specular reflection is desirable and intentional however such a large reflection would be difficult if not impossible to hide elsewhere in the car.		Moving the strobe small distances can have a significant effect on the final image. In this case the strobe was moved no more than a few feet for these examples.

If using flash equipment then you will always need to be careful positioning flashes so that they do not create distracting specular reflections. The position of the flash relative to the car and camera as well as the size of any light modifiers used will all determine the size and position of the specular reflection. Specular reflections are not a bad thing if they are very large or used appropriately. Look at the large reflections created by huge overhead soft boxes or reflectors, often 20x30 feet or larger, which can be found in many specialised car studios. Light painting can also leave a continuous highlight all along the side of a car, along the windscreen and roof, however this highlight is created with a continuous light sources which moves around the car during a long exposure.

 

1/ The reflections of 2 separate flashes can be seen in the side and rear panels. These are specular reflections or highlights.		2/ The specular reflections were almost completely eliminated by carefully repositioning the flashes relative to the camera. In this case there where still a couple of minor specular reflections under the tail light and on the plastic bumper but in many cases, depending on the shape of the car, there may be no significant specular reflections at all.
3/ Small specular reflections are also quite easy to clone out if needed whilst large reflections can be comparatively difficult to fix in post. This is why it's always best to minimise specular reflections to either minimise or eliminate any post production. The remaining small reflections where cloned out.		4/ This was the lighting setup for the previous images.

The previous page detailed techniques which can be used to minimise shadows, such as strobe placement, but in reality the specular reflection of the strobe itself is potentially far more distracting and unattractive than any shadows that may be cast. The position of any flash equipment, or any lighting, is often dictated by how that light reflects in the car itself and this is always determined by a combination of factors. The shape and colour of the car, the position of the flashes and the position of the camera itself all determine the location of any specular reflections in the car itself. When shooting from low to ground level it is common to be able to hide the reflections of the flashes in the wheel arches of the car. If shooting from a higher elevation then the flashes may also need to be raised in which case they might be hidden in a fold, corner or bend in a panel. Often a flash only needs to be moved an inch or 2 to make the difference between a large specular reflection and virtually none at all. Hiding the flashes in parts of the car may not be possible with some cars, often those without any folds or hard bends in panels.
 

These 2 flashes have been carefully positioned so that their reflections in the panels are hidden somewhere in the wheel arch. This saves having to Photoshop out a bright reflection in a panel. If the flashes were mounted high then they would tend to reflect in a panel and be time consuming to fix later.		The position of these 2 strobes caused significant specular reflections in the example above. The way to deal with these kinds of reflections is to try to move the reflections to a part of the car where they are minimised or disappear altogether. In the above example the reflections can be moved by sliding each strobe side ways until each reflection is very close to each edge of the car.
The shape of the car itself will generally dictate the degree to which specular reflections can be hidden. Some cars have curves such that hiding the specular reflections is almost impossible and the only practical solution is to minimise them with careful strobe placement and then clone them out in post. These specular reflections have not been cloned at all.		This image shows the lighting setup for the previous image. The strobes lighting the cars side where positioned to minimise the specular reflection but there was no way to eliminate them to a significant degree as is possible with most other cars.
A softbox was used to light the grille on this car because it was found that a bare flash did not create a large enough reflection in the chrome to make the chrome grille prominent. The large specular highlight created by a softbox solved the problem, making the grille stand out instead of disappearing. The side of the car was lit with bare strobes.		Here a flash was positioned so that it would create a large reflection or specular highlight in the grille of the car, purely for effect.