Reflection Sources

Learn about the different ways a PDR technician views a dent and most importantly, choosing the proper reflection for your eyes.

Fog Basics

Written by Marty Runik.

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In the last article we discussed the basics of determining which type of reflection might work best for you. Now we are ready to discuss the basics of each reflection and their strengths and weaknesses. We will start with a fog type reflection. 


There are many types of fog reflections. Some of the most common are a painted fog, shadow fog, natural fog, LED fog, and colored contrast fog. A fog reflection has several advantages. It is currently the only reflection type that will give a 3D view, a mirror image view, and a simple overhead view of any dent. Just by moving your head through the reflection in the panel you can get all of these views simultaneously. When I say a 3D view I mean that you can see a dent as though it were a 3D image with depth and contrast somewhat like you see in a 3D movie. This enables you to easily see the deepest part of your dent or crease along with seeing the relative depth of any high spots and be able to easily tell which of these areas needs to be repaired first. This characteristic is extremely useful when it comes to releasing pressure in a dent in the right sequence because you can easily compare the height or depth of any damage inside or outside the dent and know what order to repair it in for the fastest and cleanest repair.


When we talk about a mirror image of the dent we mean the ability to see a reverse image of the dent or crease just by slightly moving your head through the reflection in the panel. This comes in useful especially on deeper or more complex damage. Being able to see this mirror image will many times enable you to see around a bad reflection spot or bounced reflection inside a dent. This is a very common trouble spot with techs on larger dents. This mirror image can also help you to see your sweet spot or impact point better on deeper dents, because you can get a 180 degree different view of the dent by using this mirror image effect. Small high or low spots that can sometimes hide in the reflection can be brought out very well using this mirror image from a fog reflection.


The overhead view means being able to see a very simple top view of the dent without having it complicated by lines, edges, or other things in many other reflection types. The top view of a fog will show you the important basics of the damage and will illuminate the sweet spot (impact point) more clearly than any other reflection type, especially on deeper dents.


Using all three of these views at the same time during the dent repair makes it very easy to see not just your tool tip, but will always clearly show you the right sequence to push the dent. These views used together will also show you clearly when you are about to make an over push or show you if you even start to make a corn row because you see so much information at once. Sometimes when starting to use a fog something like information over load will happen because you see so much visual information it can be over whelming for some one who is just getting started using a fog reflection.


When doing deeper dents some fogs can be adjusted wider so you don’t get the back shadow effect a tech will notice on most standard fogs. On many fog reflections, light can bounce back and forth at the bottom of deeper dents creating very confusing effects such as circles or strange visual effects instead of a simple light and dark shade at the bottom. Fogs that can be adjusted wider will compensate for this effect and give you a nice simple look at the dent, even at the very bottom of a deep damage such as a BB gun dent or very deep crease. Another nice thing about these adjustable fogs is that they can be narrowed down to a single thin fog that many techs prefer to finish a dent. For many techs, using these fog lights will show a wider variety of information than a standard fog. 


Now it sounds like a fog has lots of advantages and no short comings for those techs that can use them. Unfortunately this isn’t true. A fogs major disadvantage is that it is VERY sensitive as to how it is adjusted. In fact a fog that is not adjusted right or is out of its visual range or “sweet spot” may confuse a tech more than it will help him. Also on horizontal damage, the fog is even harder to adjust properly because the fog reflection gets tighter (thinner) and you loose some visual information if it isn’t adjusted right on. This is why many techs use a hybrid reflection made up of a fog and a line at the edge of a reflection board to show things when working horizontally that a fog may not show well. This is mostly because you can’t adjust any reflection board past the floor when looking for some types of horizontal damage, and this means you may not be able to get a fog board back far enough too see well in these situations.


Some techs can see deep damage and fix it with a fog but can not finish with a fog no matter what they do. This isn’t due to not understanding a fog, but an inability to see the minor subtleties in a fog at the finish stage. Many techs with this problem use a shadow caster type reflection so they can get a fog and bright bulb hard line to see and work the finish.


Many techs have tried a few fog boards and conclude that a fog isn’t right for them. Before making such a decision, remember that the vast majority of techs can see well from some type of fog. Before giving up, make sure you try as many different fog types as you can. With all the different fog reflections available to a PDR tech today, there should be at least one out there that will work for you. A fog reflection is far too valuable a tool to give up on before trying everything out there. Remember, finding the perfect reflection for you is by far the most important thing you can do in PDR. You can’t fix what you can’t see!