Color mixing head

A color mixing head is an attachment for an enlarger in the photo laboratory .

With this mixing head, the color of the light can be adjusted so that the result is color-neutral or that the coloring of the final image corresponds to the specifications.

For this purpose, a cold light lamp of a defined color temperature is usually used and the light it emits is hung with colored filters in such a way that the color components can be variably controlled on the setting wheels. For this, colored glass plates ( yellow , magenta and cyan ) with more or less large proportions are brought into the light path by linear displacement.

This color filtering is particularly necessary when processing color photographs to avoid color casts on the print . In the black and white processing color mixing heads are always used when at contrast-convertible securities of different degrees of hardness of the gradation are needed and proprietary filters can not be used. There are also color mixing heads exclusively for contrast control in the black and white process.

The total brightness, which changes with this, is determined by measurement and compensated for over a longer exposure.