{"id":10153,"date":"2026-06-30T13:42:19","date_gmt":"2026-06-30T05:42:19","guid":{"rendered":"https:\/\/superpdr.com\/?p=10153"},"modified":"2026-06-30T13:42:19","modified_gmt":"2026-06-30T05:42:19","slug":"how-to-read-a-pdr-line-board","status":"publish","type":"post","link":"https:\/\/superpdr.com\/ru\/how-to-read-a-pdr-line-board\/","title":{"rendered":"How to Read a PDR Line Board: Reflection Patterns, Low Spots, High Spots, and Finishing Control"},"content":{"rendered":"
\"PDR
Line-board reflections reveal the dent center, crown, highs, and surface waves that normal lighting can hide.<\/figcaption><\/figure>\n

A PDR line board works by reflecting straight lines across a curved vehicle panel. When the panel is low, high, crowned, or wavy, the reflected lines bend. Technicians use those bends to find the exact repair point, control tool pressure, reduce highs, and confirm the final finish. Without reflection reading, PDR becomes guesswork.<\/p>\n

The line board is not just a light. It is the measuring system for the repair.<\/p>\n

Quick answer<\/h2>\n

A PDR line board turns panel shape into readable reflection lines. Tight or pinched lines usually show a low area; broken or raised line movement can indicate a high spot; wide distortion around the dent often reveals the crown that must be controlled first.<\/p>\n

What the reflection tells you<\/h2>\n\n\n\n\n\n\n\n\n\n\n
Reflection pattern<\/th>\nWhat it usually means<\/th>\nTechnician action<\/th>\n<\/tr>\n<\/thead>\n
Lines pinch inward<\/td>\nLow spot<\/td>\nPush or pull the low carefully<\/td>\n<\/tr>\n
Lines spread outward<\/td>\nHigh spot<\/td>\nKnock down or blend the high<\/td>\n<\/tr>\n
Lines curve around dent<\/td>\nCrown around impact<\/td>\nReduce crown before lifting center<\/td>\n<\/tr>\n
Lines look wavy after repair<\/td>\nUneven finish or tool marks<\/td>\nMicro-adjust with tip and knockdown<\/td>\n<\/tr>\n
Lines disappear in glare<\/td>\nPoor light angle<\/td>\nReposition board or change contrast<\/td>\n<\/tr>\n
Lines move sharply with small pressure<\/td>\nSharp low or high<\/td>\nUse smaller tool movement<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Set the board before reading the dent<\/h2>\n

A common beginner mistake is changing the board angle too often. If the board moves constantly, the technician cannot compare progress. Set the board so the dent, crown, and surrounding clean panel are visible. The reflection should cross the damage area with enough contrast to show line movement.<\/p>\n

For a small door ding, place the board so lines run through the center and across the crown. For a crease, align the reflection so the length of the damage is readable. For hail damage, choose a consistent light position that lets the technician move from dent to dent without losing orientation.<\/p>\n

Low spots versus high spots<\/h2>\n

A low spot pulls the reflection inward. A high spot pushes the reflection outward. This sounds simple, but the pattern depends on board angle and panel shape. The technician should compare the damaged area with the clean surrounding panel.<\/p>\n

The goal is not to make one line straight at one angle. The goal is to restore stable reflection across several viewing angles. A dent that looks fixed from one position may still show waves from another.<\/p>\n

Reading the crown<\/h2>\n

The crown is the raised tension around the dent. It is often wider than the visible low. If the technician ignores the crown, the center may resist movement or overpull.<\/p>\n

A crown can appear as lines that bend outward around the low. Before pushing or pulling the center aggressively, reduce the crown in controlled steps. This lets the low rise more naturally.<\/p>\n

Crown control is especially important for:<\/p>\n

    \n
  • Sharp door dings.<\/li>\n
  • Long creases.<\/li>\n
  • Body-line dents.<\/li>\n
  • Hail dents on tight panels.<\/li>\n
  • Aluminum panels.<\/li>\n<\/ul>\n

    Tool tip control through reflection<\/h2>\n

    When using rods or hooks, the technician should see the tool tip appear under the low in the reflection. If the tip appears beside the low, the push may create a high spot. Small movements matter.<\/p>\n

    A useful learning sequence is:<\/p>\n

      \n
    1. Place the tool tip behind the panel.<\/li>\n
    2. Make a very light pressure point.<\/li>\n
    3. Watch where the reflection moves.<\/li>\n
    4. Adjust tip position before applying stronger pressure.<\/li>\n
    5. Push in micro movements.<\/li>\n
    6. Stop and reduce highs early.<\/li>\n<\/ol>\n

      This process trains the hand to follow the eye.<\/p>\n

      Glue pulling with a line board<\/h2>\n

      Glue pulling also needs reflection. The tab should be placed on the true low, not just the center of the visible mark. After each pull, inspect for overpull. A high created by glue pulling may need knockdown before the next pull.<\/p>\n

      For crease tabs, the board helps align the tab with the damage line. If the tab is angled incorrectly, the pull may twist the low or lift only one side.<\/p>\n

      Finishing control<\/h2>\n

      The final stage of PDR is often slower than the first lift. The dent may be 80 percent improved quickly, but the last texture requires careful line reading. Finishing includes:<\/p>\n

        \n
      • Small tip pushes.<\/li>\n
      • Light knockdown taps.<\/li>\n
      • Crown blending.<\/li>\n
      • Checking multiple reflection angles.<\/li>\n
      • Comparing repaired and unrepaired panel texture.<\/li>\n<\/ul>\n

        A technician should avoid chasing one tiny line movement until the whole panel is unstable. The correct finish is a balanced surface, not an isolated correction.<\/p>\n

        LED light versus fog board versus striped board<\/h2>\n

        Different boards reveal different information:<\/p>\n

          \n
        • A striped line board is strong for seeing lows and highs clearly.<\/li>\n
        • A fog board or gradient board helps read subtle waves and finishing texture.<\/li>\n
        • An LED light board is useful in shops and mobile work, especially with adjustable brightness.<\/li>\n
        • A battery-powered board improves mobile workflow but must have reliable power and mounting.<\/li>\n<\/ul>\n

          Many technicians use more than one lighting style. The important point is consistency and readability.<\/p>\n

          Common line board mistakes<\/h2>\n
            \n
          • Setting the light too close and creating glare.<\/li>\n
          • Reading only the center of the dent.<\/li>\n
          • Moving the board after every push.<\/li>\n
          • Ignoring crown movement.<\/li>\n
          • Finishing from only one viewing angle.<\/li>\n
          • Using a light but no knockdown control.<\/li>\n
          • Assuming a normal photo can replace reflection inspection.<\/li>\n<\/ul>\n

            Super PDR tool path<\/h2>\n

            Super PDR line boards, LED inspection lights, rods, glue pulling tools, knockdowns, and hail repair sets should be used as one workflow. A light board helps the technician decide which rod tip, tab size, puller strength, or knockdown action is appropriate.<\/p>\n

            For buyers, a PDR kit without a reflection tool is incomplete. For distributors, line board quality should be evaluated by brightness, contrast, stability, power reliability, mounting options, and visibility on different paint colors.<\/p>\n

            Practice routine for learning reflection reading<\/h2>\n

            Line-board skill improves fastest when the technician separates seeing from pushing. A useful training routine is to use a practice panel with a few known dents and repeat the same inspection steps before any tool pressure is applied.<\/p>\n

              \n
            1. Place the board and do not touch the dent yet.<\/li>\n
            2. Mark the apparent center of the low with a removable marker.<\/li>\n
            3. Move your head slightly and confirm whether the center changes.<\/li>\n
            4. Identify the outer crown before selecting a tool.<\/li>\n
            5. Apply one very light tool pressure point.<\/li>\n
            6. Stop and describe what the reflection did.<\/li>\n
            7. Correct the tool position before adding force.<\/li>\n<\/ol>\n

              This routine prevents the common habit of pushing before seeing. It also helps a trainer diagnose whether the student has a tool-control problem or a reflection-reading problem.<\/p>\n

              Final inspection checklist<\/h2>\n

              A finished panel should be checked with more than one light position. Use this checklist before calling a repair complete:<\/p>\n

                \n
              • The main low is gone under the primary reflection.<\/li>\n
              • The crown no longer distorts surrounding lines.<\/li>\n
              • No isolated high spots remain from tool pushes or overpulls.<\/li>\n
              • The panel texture looks consistent with the nearby original surface.<\/li>\n
              • The repair does not disappear only from one angle.<\/li>\n
              • The paint surface has no new marks from tips, tabs, or knockdowns.<\/li>\n
              • Trim, seals, and access areas are clean after repair.<\/li>\n<\/ul>\n

                For B2B buyers, this is why the light board should be considered a quality-control tool, not only a repair tool. A shop can use the same line-board method for technician training, customer explanation, and final inspection.<\/p>\n

                Short FAQ<\/h2>\n

                Do I need a line board for DIY dent repair?<\/h3>\n

                Yes, if you want to understand the surface instead of guessing. Even a simple line board helps reveal whether the dent is low, high, or wavy.<\/p>\n

                Why does the dent look fixed in normal light but not under a line board?<\/h3>\n

                Normal light hides small surface distortion. A line board exaggerates reflection changes, which makes remaining highs and lows visible.<\/p>\n

                What do bent lines mean?<\/h3>\n

                Bent lines mean the panel surface is not following the expected shape. The direction of the bend helps identify lows, highs, and crowns.<\/p>\n

                Can a PDR light board diagnose cracked paint?<\/h3>\n

                It can help reveal surface texture, but paint cracks need close visual inspection. Do not rely only on reflection.<\/p>\n

                Related Super PDR content<\/h2>\n
                  \n
                • PDR Tool Selection Guide<\/li>\n
                • PDR Glue Pulling Troubleshooting<\/li>\n
                • Hail Damage PDR Workflow<\/li>\n
                • PDR Tool Maintenance FAQ<\/li>\n
                • Super PDR products: \/products\/<\/li>\n<\/ul>\n