My positive plates had been taking too long to expose and the image was muddy,so I consulted Lea's manual of photography and found the answer.

The Silver bath had built up too much acid and could be saved by adding baking soda. Now I am back up to the exposure times I had befor.

If your silver bath has been used or sat for a long time it should probably be deacidified once in a while. Pour the silver solution into a jar and add a little baking soda and stir then let settle for a few minutes,test with litmus paper, it shuld turn a slight pink, if too red add more soda. Filter back in to your container and give it a test. The speed shuld be back to normal and if there is any fogging add nitric acid a drop or two at a time untill the shadow areas are clear.

Ammonium Hydroxide is another option. Buy it at "industrial strength" which I believe is 28%. Use a dropper and add very slowly with agitation, checking with pH paper after each few drops. You'll see a black precipitate form when the drops hit the bath. It will then dissolve.

My big bath holds about 5 quarts of solution. I can equalize the pH (to 7.0) with 12 - 20 drops starting at pH of 3.0. So this is strong stuff.

Do this outdoors, as the odor and bite of Ammonium Hydroxide at this concentration is like, well like tear gas!