An optical reading including a device for effecting discrimination between a dither-matrix reading area and a non-dither-matrix reading area on a subject copy, an irradiating device for irradiating local segments of the subject copy with light beams having different intensities, a reading device for obtaining image data representative of the presence or absence of an achromatic tone in each local segment based on an amount of the light beam reflected by each local segment, a control device for operating the irradiating and reading devices to irradiate the local segments in a predetermined discriminating zone of the subject copy with the light beams having different intensities at different times, to obtain first and second image data, a device for comparing the first and second image data of each local segment in the discrimination zone, to determine whether the first and second image data agree with each other or not for each local segment, and a device for determining that the discrimination zone is the dither-matrix reading area, if a degree of disagreement of the first and second image data exceeds a predetermined reference value, and determining that the discrimination zone is the non-dither-matrix reading area, if the degree of disagreement does not exceed the reference value.
Optical reader having apparatus for discrimination between dither-matrix and non-dither-matrix reading areas, and/or means for determining light emitter drive power values by using reference reflector surface