To maximize accuracy, this recent releases of ZipGrade have more strict default settings in acquiring an image. Depending on what messages appear, we can either adjust these settings or know how to change the sheet or environment to speed up the scanning.
When scanning, pay attention to the message that shows while the image seems most scannable:
Is it 'Waiting For Autofocus'? If so, visit the 'Settings' screen either by pressing the gear icon on the scanning screen (if visible) or using the menu icon in the upper-left on the main screens to reveal the slide-out menu to show the 'Settings' link. On the 'Settings' screen, find the slider labeled 'Required Image Sharpness' and move it to the left a bit. Try again and repeat until the image focus seems reasonable and it picks up.
Is the message 'Bright Light Detected'? If so, this means that the app is seeing a brighter white inside a circle than anywhere else. This usually occurs when there is some type of bright, direct light causing a glare on the answer sheet and is reflecting off a pencil mark. This situation has historically caused more mismarks than any other issue. If possible, move to a different location (ie other side of the desk) to remove the glare from the circles. If you absolutely cannot go beyond this message, you may disable the 'Bright Light Detection' setting in the settings.
If the message 'Verifying Correct Form' or 'Hold Paper Flat'? In this case the app is unable to find all the dark squares where they expect them. If you've customized the legacy forms and removed any of the internal black squares or the copy machine didn't recreate the squares very well, this message will also appear. In this case, on the 'Settings' screen move the slider labeled 'Sheet Strictness' about 1/4th to the left and try again. Repeat until the form is readable.
If you continue to have issues, please exit the ZipGrade app and use the Camera app to take a picture of the answer sheet form and email that to firstname.lastname@example.org. With that picture I can better debug where the app is failing to recognize the form. Please be sure to include your ZipGrade username and the quiz you are working with.