Quote:
Originally Posted by Photo Engineer  This emulsion is an SRAD (Single Run Ammonia Digest) emulsion similar to the one I posted earlier in this forum. It is a good formula which will work reasonably well.
It will be slightly slower due to the fact that the gelatin level is higher from what I see. As gelatin goes up, grain size goes down and therefore speed decreases.
The ammonia is 28%. DO NOT USE HOUSEHOLD AMMONIA. It is too dilute and will result in a poor emulsion. You must get the 28% from a chemical supply house. Also, be aware of the extreme fumes produced by this method. You will need good ventilation.
Try it, it will work.
Oh, chrome alum is indeed a hardener, and if you have not washed out all of the ammonia it will harden rather quickly.
PE |
pe i dont mean to dvert this thread and appologise if i doso
i can get 250mg of 250 bloom 'photo gelatine "actvated"(?) for $50
it is presalted afaik for a agno salt emulsion-included is a book of instructions and methods he uses-very comprehensive-the combination of the book and the gelatine may be worth the price?-i am moving towards the salt emulsion anyway-he gives emulsion speeds from 1/2-5 iso in different applications and coatings
he also adds iodides and bromides for more speed and other reasons
if i sh ould address this elswhere please tell me
vaya con dios