How the positive is achieved?
Normal processing for Zebra Dry Plates results in a black negative but since with Zebra Tintypes emulsion is coated on black surface a special developer mixture is needed. Your goal is to make the negative white and you can achieve that by adding Ammonium Thiocyanate to the preferred developer (they are listed in our Developing Charts).
*More info on how to use these Dry Plate Tintypes can be found HERE
**DEVELOPING CHART for Zebra Dry Plate Tintypes is available right HERE.
***Exciting news! We have expanded our product range at Darkroom Chemistry to include Ammonium Thiocyanate in our store which can be ordered right HERE.