Method of and arrangement for reading a bar code on photographic material

A bar code is scanned to generate a signal which is representative of the bar code and contains a series of maxima and minima. The signal is sampled to detect the maxima and minima corresponding to the encoded information of the bar code. The detected maxima are compared with an upper threshold value while the detected minima are compared with a lower threshold value. For each detected maximum and minimum, a "0" or "1" is entered in a memory depending upon whether or not the detected maximum or minimum exceeds the corresponding threshold value. This produces an array of bits which is then decoded.