20 between the cylindrical portions of the sleeves 16 and 17 the sleeves 16 and 17 are connected with one another by means of baffles 21 which are spaced one from another and extend across the passage 19 between the sleeves 16 and 17 the inner surface of the sleeve 16 and the outer surface of the sleeve 17 that is the surfaces facing each other are provided with a number of rims 23 and 22 respectively which are spaced from one another along the length of the passage 19 and extend partially across the passage 19 so as to overlap one another such a location of the rims 23 and 22 relative to one another prevents any light penetration through the passage 19 into the interior of the tank 10 the passage 19 and the channel 20 serve to ensure fast filling or emptying of the developing liquid therethrough in from the tank 10 the first sleeve 16 is provided at its lower inner portion with an annular rim 24 which has a sealing washer 25 located between the rim 24 and the inner surface of the thread portion 14 a two piece slotting cartridge 26 is located on the bottom 12 between the ribs 13 the cartridge 26 defines a place for installing a film reel 28 with a film 27 to be.