Bubble Sheet Scanning - Best Practices (includes VIDEO)


If scanning is slow or not happening or if, when you get a scan, an alert is displaying about anomalies, this article can help!
Is scanning slow or not happening? 
Scanning should be very fast, but maybe, in some way, the camera isn't capturing a scannable image. See the video below or the Basics of a Good Scan section below it.  

Are you getting too many anomalies? 
When there's a question with no bubbles filled in, or too many bubbles filled in, etc., we highlight those in pink for you to make a determination. 

There are three kinds of anomalies: 

  • Questions left blank by the student or because they are manually graded questions. Either way, you'll need to make a determination and score these.
  • Single-correct-answer questions with two or more bubbles filled in OR multiple-correct-answer questions scored as incorrect. By request, these are anomalies so that if students misunderstood instructions or didn't correctly erase unintended bubbles, etc., the teacher can make a determination. 
  • Filled-in bubbles not clear to the camera because they are filled in too lightly or overhead lights are reflecting off of pencil lead or lamination. Reflections are the #1 cause of anomaly clusters. For an easy solution, see either the video below or the  section below it. 


 Basics of a Good Scan:




  1. The camera angle is straight-on, not skewed.
  2. The outer black rectangle is fully in frame.
  3. Filled-in bubbles are clearly visible, with no reflections off pencil lead or lamination.
  4. Lighting is even, with no shadows, bright spots, or reflections.
  5. The bubble sheet is flat, not wrinkled, or curved.
  6. Unintended answers are completely erased, not crossed through.
  7. The bubble sheet is good quality (not a washed-out or darkened "copy of a copy," not shrunken or altered).
  8. The image is detailed, in focus, and the lens is clean.
  9. There are no extra markings or writing around the rectangle, bubbles, or QR code.

Common Problems and How to Fix Them




Problems with this image:

The camera is not directly over the bubble sheet but is at a skewed angle.


Move the camera so that it is directly over the sheet looking straight at it, or if you are holding the sheet up to the camera, be sure it is straight-on and perpendicular with the camera.


Curves or Shadows  

Problems with this image:

This page is curved, there are dark and bright areas, and not all regions are in focus!


Place the bubble sheets on a flat surface to scan. If you are holding the sheets up, be careful to not curve them - try using a book or clipboard to hold them straight and flat.

Arrange the scanning environment to eliminate shadows so that the lighting is even. Turn off any close-up camera light that may be creating bright spots.


Pencil Marks Reflective or Too Light



Problems with this image:

The pencil marks for questions 1-15 are reflecting overhead lights. It’s hard to tell they are filled in. These will all be marked as anomalies!

Also, sometimes pencil marks are just too light.


Turn off direct-overhead lights or change scanning location or the angle of the page to avoid the reflection.

If the pencil marks are just not dark enough, instruct students to make them darker or use pens or markers.



Reflecting Ink or Lamination


Problems with this image:

We encourage laminating or using sheet protectors with dry erase markers, but it can easily cause reflections and glares when scanning.

Also, some printer inks are reflective, making them unreadable.


Turn off overhead lighting or find a better angle that avoids reflections from overhead lights, sunlight, etc.


Rectangle Cut Off or Obscured

Problems with this image:

The rectangle surrounding the bubbles is not fully in frame.

This can also happen if you have obstructions over part of the page, like loose papers or even obscuring marks.


Get the rectangle fully in frame with a little space around the edges.

Also, avoid any obscuring of the black rectangle, QR code, or any bubbles by any object, extraneous marking, or even dark shadows.


Markings On or Within Rectangle



Problems with this image:

There are extraneous markings and writing too close to and on the black rectangle, the QR code, and the bubble area.



The rectangle, QR code, question numbers, and bubbles need to be free from obstructions or markings other than bubbles being filled in.




If you were looking for help with other scanning issues, click here for help.


If this article described your problem, but you are still having trouble, contact Tech Support for more assistance!



additional keywords: not working, errors, wrong, grading, accurate, inaccurate, bubbles, reading,

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