Rinsing plates

Plaque sortant du bain de dégorgement (eau froide)
Plate going aout disgorging bath (cold water)
  • At the end of sunstroke, we have to see the complete image, in slightly brown color, with all its details, even in its halftones.
  • After the sunstroke, patches are put in the tank to be cleared containing some pure water. Attention on the strongly chlorinated water. Remember that the sodium hypochlorite dissolves the gelatin (see the section Cleaning of glass). If we can it, we renew at least once the water during the phase of draining. This wash has the effect of dissolving the metallic salt contained in the gelatin, which, at this stage of the operations does not have to act any more, its action being ended. We realize easily its disappearance by the tint of the gelatin which takes back its natural color and loses any colored track.
  • Plaque sortant du bain de dégorgement (eau froide)
    Plate going aout disgorging bath (cold water)

    Draining : it is necessary to remember that the water disgorging bath, which seems to be a simple phase, quite has to hold attention on a very particular point which is the temperature of the water! Indeed, if the temperature of the water of draining is too high (superior to 63 – 64 ° F), the image will have of the grain and the whites of the image will tend to shadow themselves. In summer, the duration of draining is from 3 to 5 o’clock. In winter or with a very cold water ( temperature below 12°C) the average duration is from 10 to 12 o’clock. In a fresh water, the plate(patch) can stay there until the next day morning if need, without prejudice. Plunge of a sudden the totality of the plate into the water to avoid irregularities which can form on the surface of the gelatin (without consequence on the final result). The water is maintained in a temperature the closest to 50 ° in 54° F, and does not have to exceed(overtake) 61° F. During the hot season of the summer, the water must be refreshed. At the release of the bath of draining, wipe the gelatin with a squeegee. Let dry naturally upright on an easel with wide grooves, or in quite different place and position which will allow the remaining water to pass by and in the plate to dry naturally. If need, the drying can be accelerated by means of a ventilator (not heating otherwise the gelatin bottom!). At the beginning of the drying, when the plate is drained but still widely wet, the image takes shape in its slightest detail and with a lot of delicacy, when we look at the glass in shaving light. It is a really impressive vision (photo opposite)!

  • IMPORTANT : if you use dichromate, retain that the rejection of dichromates in
    rinçage de la gélatine après insolation
    Visible images on not inked plate

    sewers is forbidden. You can however add some sulphite of sodium in the water of rinsing before rejecting it. The dichromate ( Cr VI) being very toxic, must not be rejected in the natural environment, but neutralized before rejection (transformed into Cr III). The quantity of sulphite of sodium to be added in the water is of half of the used dichromate. To consult the index form toxicologique INRS.