CHAPTER 4
WASHING OF SILVER GELATINE EMULSION

WASHING EMULSIONS REFER TO  F I G U R E 1 Step By Step. Wash Under Red Safe Light illumination. in Fig 1, is shown all you need to wash 250 – 500 ml of Emulsions intelligently. SUMMARY OF STEPS:
Emulsion B in dish C is set into a jelly in tray E, cooled with ice cubes D, set emulsion is scraped off dish C, with spoon F, onto the shredding net G, which is then gathered into a ball and twisted so as to force the stiff emulsion through the mesh opening forming shreds or noodles.
This is done under ice water in washing tank H. The noodles or emulsion shreds are then inserted into the linen bag J, by means of wide mouth funnel the emulsion enclosed in the linen bag J, is now suspended or immer-sed in washing tank H for washing, drawing clean ice water from fresh water supply tank K,
After of about 5 minutes washing the spent water is dumped in waste water tank M. To cool the washing water, ice cubes are taken from ice cube supply tank L, the amount of water is measured with measuring cup o and the washing time is controlled with minute timer N.,  This tank H, will also serve as the emulsion washing tank in the following manner: When 2 liters of fresh ice water ( which may be drawn from with measuring cup O) taken from fresh water supply tank K, are added to washing tank H, tank H will be half full then and this will be enough water to cover the emulsion bag (step 7  way below) if not, more fresh water may be added from fresh water supply tank K, until there is enough water to cover the bag containing the emulsion.
At the end of about every 5 minutes of having immersed (with frequent agitation) the emulsion bag inside the ice water in washing tank H, the water is ready to be changed, to effect this, the used water is dumped in waste water tank M, then another 2 liters of new water is drawn from fresh water supply tank K, after another 5 minutes, the cycle is repeated again dumping the used water and replenishing with Fresh one from fresh water supply tank K.
K, is a about a 4 liters capacity jar filled with clean water to wash the emulsion. Since it does not contain all of the quantity of water required for washing the emulsion, it will have to be refilled from time to time with fresh water to replace the water used during the course of the emulsion washing. The clean water supply in tank K has to be continually cooled by drawing ice from ice cube supply tank L which is an ice cube supply tank to keep adding to fresh water supply K, to keep its fresh water cooled to the point of melting ice, (to 5c / 41 f or below) otherwise the emulsion jelly will absorb too much water.
(especially with room temperature above 25c) no need to measure the temperature of the fresh water supply tank; as long as there is un melted ice cubes floating in the water because in such case the temperature will be 5c ( 41 f ) or below. The colder the better. Ice must also be added from time to time to water of washing tank H, to keep its water cool this is of the utmost importance M, is the waste water tank, where the spent or used emulsion water is emptied. It may be about 8 liters capacity (2 gallons) after each 5 minutes or so of washing emulsion with fresh water in washing tank H, the spent water is thrown or discarded in this waste water tank M, Since It fills up quickly, (especially with ammonia emulsion which require much longer washing) when it does, it has to be emptied by dumping its contents down the drain or sink. N, is a minute timer which is set to ring the bell every 5 minutes to signal the beginning of a new change of fresh washing water.

MORE ON EMULSION WASHING
Refer To “ Emulsion Washing in 7 steps ABOVE “
(See Step 1 above) The time the emulsion is let in the ice tray E, is usually about 30 minutes (with room temperature 20-25c) or until it has set into a stiff jelly, when as firm as a hard rubber ball, (fig 2 ABOVE) with stainless steel spoon with gelatine now set emulsion is placed onto the shredding net and it is shredded by forcing it to pass through the openings of the net (fig 3 - 4 )
This emulsion shredding step (so shreds do not stick together) is done inside washing tank Step 5 , previously filled with enough ice water. This tank should have a capacity of about 4 liters (1 gallon) with a wide mouth to immerse both hands comfortably to shred emulsion... (Step 5 ) ,After shredding emulsion is enclosed inside linen bag for washing: STEP 6 and the bag with the emulsion noodles immersed in ice water to wash,STEP 7.   EMULSION WASHING IN 7 STEPS. Emulsion Washing Data for 250 to 500 ml of Emulsion Full Ammoniacal emulsions require at least 12 changes of water with frequent agitation while neutral non Ammoniacal emulsions can be washed with 4 - 6 changes. The amount of ice needed depends on room temperature, if above 25c more ice, if below 22c, less is needed. Since the free bromide in the emulsion washes out faster than the ammonia, the silver may end up in excess of the bromide causing fog on alkaline development. To avoid this fog due to over washing; -add the free bromide (as given below ) to the washing water, for ammonia emulsions only (with experience even less than half the amount of washing water given in table below can be used; - this is important for economy when washing with distilled or rain water on localities where the tap water has too much calcium or magnesium)
IN TABLE ABOVE
Fig 2 The size of the washing bag J, shown above, for a more effective washing should be large enough to accommodate all of the emulsion noodles or worms, plus 2 – 3 times the emulsion volume in free space. In this way there will be enough free space inside the bag to move the emulsion around during washing. Thin Linen fabric the type used to make bed sheets or handkerchiefs is adequate (cotton is too heavy and absorbs too much water) synthetic fabrics absorb less water and are excellent as long as the fabric is thin and finely knitted. For 250 – 500 ml of emulsion, a bag size 15 x30 cm (6 x 12 in) is fine.
Fig 3 Shredding Net G, above shown is a section of a polyester net used for shredding the chilled and set emulsion. These nets are used for packing fruits and vegetables. Net above came enclosing 1 kilo of carrots. Mesh openings shown are about 7 mm wide but can be a little smaller or larger. A net size 20 x 25cm (8x10 in) for shredding 250 – 500 ml emulsion works fine, the larger the better. If the whole volume of the jellified emulsion can not be shredded all at once, It can be shredded in portions scraping it off the emulsion dish in amounts that will fit well on the size of the net used and that can be shredded comfortably under the ice water, so fragments will not stick together.