Suggested BoxColor for gray-scale-printed answersheets

Added by Roberto González almost 9 years ago

Hi everybody:

I'm testing AMC at my school, where we only can print documents using grayscale (we don't have color ink).
What BoxColor value do you think would be a better choice (for answer sheet boxes): black or lightgray?

I know that it would be better to perform a test by myself, but I'm very busy and it's a kind of emergency (next week we are going to get visited by hundreds of students that will apply to our school, and we need to process the results of the tests that will be applied to those students as fast as we can.

I have seen a video on youtube (http://www.youtube.com/watch?v=fhJ4bnU6Qkk) and the answer sheet seems to have black boxes with black letters inside.

Thanks in advance.

Roberto.


Replies (5)

RE: Suggested BoxColor for gray-scale-printed answersheets - Added by Alexis Bienvenüe almost 9 years ago

I'm always using black boxes with no problem (without separate answer sheet), but lightgray could help AMC to ignore the boxes and focus on the drawings from the students. However, they should be well visible when printed!

RE: Suggested BoxColor for gray-scale-printed answersheets - Added by Roberto González almost 9 years ago

Alexis Bienvenüe wrote:

I'm always using black boxes with no problem (without separate answer sheet), but lightgray could help AMC to ignore the boxes and focus on the drawings from the students. However, they should be well visible when printed!

First of all: thank you very (really, VERY) much for your immediate answer.

The tests that our school will apply to those students were made by an external educational institution, so we didn't make them with AMC. Therefore, we will give each student a single separate answer sheet to fill in the boxes (the test itself is an absolutely independent printed document). From that perspective, I´m afraid of printing a lot of unuseful sheets and, even worse, to be unable to process the answers of hundreds of students without the help of this wonderful tool (everything here is a matter of time optimization).

As you said, boxes should be well visible when printed, but after printing a sample answer sheet with ColorBox: lightgray, I realized that this option doesn't fit this requirement. Then, I think maybe the best choice is one of the following:

1) Black or some slightly-dark gray.
2) Same as before, but putting letters outside the boxes.

Have you ever tried somethig like this with a separate answer sheet?

Thanks in advance.
Roberto.

RE: Suggested BoxColor for gray-scale-printed answersheets - Added by Alexis Bienvenüe almost 9 years ago

Have you ever tried somethig like this with a separate answer sheet?

Not me (perhaps other users will share their experience?).
You will have to adapt instructions given to the students to your choice:
  • If you choose to draw letters inside the boxes, tell them to darken the boxes entirely, otherwise AMC won't be able to make any difference between a box with a letter as E and a box with a letter as I and some little cross, for example.
  • If you choose to draw letters outside the boxes, you can let them free to tick the boxes or darken them entirely (as far as they don't tick them too lightly, but I experience very few problems of this kind...)

RE: Suggested BoxColor for gray-scale-printed answersheets - Added by Roberto González almost 9 years ago

  • If you choose to draw letters inside the boxes, tell them to darken the boxes entirely, otherwise AMC won't be able to make any difference between a box with a letter as E and a box with a letter as I and some little cross, for example.

This leads me to the following doubts:

1) How do I tell AMC that a box must be considered as 'marked' when it is entirely darkened, and not in any other case (for example, when it has an 'X' inside)?

2) Does it mean that AMC won't be able to correctly detect student's answers if it can't recognize the letters inside the boxes?
(I believed that AMC identified the marked alternative by detecting the relative position of the corresponding box inside the answer sheet).

RE: Suggested BoxColor for gray-scale-printed answersheets - Added by Alexis Bienvenüe almost 9 years ago

  1. This is a job for the parameter darkness threshold. For each box, AMC computes the ratio of dark pixels. If this ratio is greater than the darkness threshold, the box is considered as ticked. When you ask for letters inside the boxes, AMC will automatically propose you to set the darkness threshold value to 0.5 (if not already greater than that). Otherwise, maybe a value near 0.15 or 0.20 is correct (but this can depend on your environment – scanner, pencils used by the students, etc.
  2. no.

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