Sprinkle light-colored power -- such as talcum powder or chalk dust -- on dark, nonporous surfaces, or sprinkle the dark-colored powder -- such as coco powder or carbon dust -- on light, nonporous surfaces. Be careful not to throw large amounts of powder on the print, as this may obscure it. Carefully brush away the excess powder using light strokes. Reapply powder as necessary, brushing it away until you have a complete fingerprint.
Press the clear tape over the dusted fingerprint, picking up what is known as the "impression." The dust transfers to the tape, preserving the fingerprint. Carefully peel up the tape, and press it to an index card, making sure the tape is completely smooth against the card and cannot be peeled off. To ensure the print will not be removed from the card, press down the corners of the tape.
Label the index card with where you found the print, what surface the print was found on and the date and time that the print was found. If you can determine it, also include what finger you believe the print is from. File the print in a safe place.