Bubble Sheet Scanning Not Working Well? (includes VIDEO)

• The camera angle is straight-on, not skewed at an angle.

• The bubble sheet is flat, not wrinkled or curved.

• The black rectangle is fully in frame, with a little space around the edges.

• Filled-in bubbles are dark in the viewer, fully filled in, with no reflections off the pencil lead that can look lighter.

• The lighting is even, with no shadows, bright spots, or reflections off of pencil lead, ink, or lamination.

• The quality is clear, sharp, in focus, and the camera lens is clean.

• The bubble sheet printout is unaltered and good quality.

• There are no extraneous markings or writing on or within the black rectangle area.

Skew

Problems:

The bubble sheet not straight on and perpendicular to the camera. The rectangle around the bubbles looks like a trapezoid.

Some areas are in focus while others are not because the distances to the camera are different.

Solutions:

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:

Curves in the page make the lines of the rectangle appear bowed rather than straight.

Some areas are in focus while others are not because the distances to the camera are different.

In this example, light is uneven, with bright spots and shadows. Shadows are sometimes caused by objects around the sheet, like the camera stand. Built-in lights on cameras can also cause bright spots.

Solutions:

Place the bubble sheets on a flat surface to scan. If you are holding the sheets up, don't curve them - try using a book or clipboard to hold them up straight and flat. Eliminate shadows or bright spots. Turn off any camera light that creates bright spots.

Pencil Marks Reflective or Too Light

Problem:

The pencil marks for questions 1-15 are reflecting overhead lights and it's hard to tell they are filled in.

Sometimes pencil marks are just too light.

Solution

Turn off direct-overhead lights, or change scanning location to avoid the reflection.

Change angles between your scanning setup and any light sources to eliminate reflections.

Pencils work well, but the marks need to be nice and dark. Have your students go back over their bubbles or try markers or pens.

Reflecting Ink or Lamination

Problems:

Reusing sheets with lamination (or sheet protectors) and wet erase markers is a great way to cut costs and add convenience, but the chances for reflections and glare increase.

Some printer inks are also reflective, and this can cause problems during scanning.

Solutions:

Turn off direct-overhead lights, or change scanning location to avoid reflections.

Change angles between your scanning setup and any light sources to eliminate reflections.

Rectangle Cut Off or Obscured

Problems:

The rectangle surrounding the bubbles is not fully in frame.

Also, any obstructions over part of the rectangle (not shown in this example) like fingers, marks, or loose papers can obscure the rectangle.

Solutions:

The rectangle is critical to scanning, so back your camera away from the sheet so that the rectangle is fully in frame with a little space around the edges.

Avoid any obscuring of the black rectangle, QR code, or bubbles by any object or dark shadow.