Francesco;

The SRAD (Single Run Ammonia Digest) emulsion that I posted here has been repeated by others with varying degrees of success. Basically though it can give a speed of about ISO 25 - 80, average of 40 with good lab technique. By adding a green and a red sensitizing dye, you get a pan emulsion. Green sensitizing dyes are easy to get. Red sensitizing dyes are harder to get. I have one dye that I posted here which gives me Red sensitivity with Br/I emulsions but others have not been able to get it to work.

If it does work, you need to carry out all work in total darkness or IR.

In addition, you need a source of subbed support for film coatings or you are locked into plate coatings more or less.

With most dyes, the procedure is to make the emulsion up to the point of coating but before adding the surfactant and hardener. At this point add the sensitizing dye(s) and hold at 100 - 115 deg F for 15 minutes. Then add the surfactant and the hardener and coat. You may have to split the emulsion into 2 parts, one red and one green as the dyes often interfere with each other, or you may have to get one broad dye to do combined work as red and green.

The problem is that the exact quantity of dye to be used is critical and must be determined by trial and error with each emulsion. I generally use about 50 - 100 mg of dye/Mole of Silver. If you use too much or too little you don't get the desired speed. You also have to have a method to measure the sensitivity to check out if it worked.

PE