Digitising Text

This article was originally published in November 2014.

Since school, I have maintained a little black diary containing the signatures of my favorite teachers. Now, the paper is slowly turning yellow. I would not want to lose any of these treasures, and would like to have a digital copy of each page. How do I shoot it effectively so that the text can be clearly read?
Shreya Mathur, Mumbai, via e-mail

That is quite a sweet practice and photography is surely one way to preserve the autographs. However, there are a few problems that you need to be wary of. The paper should not become dark, the text should be sharp and clear enough and there should be no colour cast. All of this would spoil the original feel of the document. Place the document near a window that receives enough natural light. Set up the camera on a tripod above the document. The plane of the camera should be exactly parallel to the paper, so that it is rendered sharp. Use an aperture that is neither too wide nor too narrow—like f/8 or f/11. This will ensure that the DOF is reasonably large and the lens is optimally sharp. The other two settings you will need to look at, are White Balance and exposure. You need to experiment with different WB presets so that there is no colour cast. Finally, remember that if the pages of the diary are white in colour, the default Evaluative or Matrix metering mode of the camera will result in a picture that is slightly underexposed. To deal with this problem, press the Exposure Compensation (+/-) button and use a value of +0.5EV or +1EV.