I'm guessing this isn't going on a commercial press, but this is what I consider.
1. Scan for approximately 300dpi when it's being reproduced at 100%. It allows you to enlarge a photo to about 120% without having to worry about pixelation occurring.
2. What's the software you're manipulating the photos within? If you're doing image editing in Photoshop, scan in colour to achieve the best colour depth, then use the Channel Mixer to control the grey values. (Mode > Adjustment > Channel mixer (click on Monochomatic)
3. Change the colour mode to grey scale and import into your favourite page layout software.
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