Would like to share a few notes on the use of Pyrocat-HD, and some modifications to the formula. First, let me comment that the Pyrocat-HD formula is in the public domain, and although it is sold through various sources in the US and in Europe I am not involved personally involved in those enterprises. OK, here are the notes. A. SLIGHT CHANGE IN THE FORMULA If you are currently mixing your own Pyrocat-HD stock solutions from scratch I have made a slight change in the formula for Stock Solution A. When mixing from scratch I am now recommending only 0.1g of potassium bromide for 100ml of Stock A, (or 1.0g for 1000ml of Stock A). In some situations the change will result in a very slight improvement in film speed, with no adverse results. I will communicate this change very soon to the folks at B&S and PF who supply Pyrocat-HD in kit form. However, this is a very minor change so don't throw away your old Pyrocat-HD kits as it would take some very good sensitiometry to see the difference. B. MIXING STOCK SOLUTIONS WITH GLYCOL On mixing Pyrocat-HD in Propylene Glycol. As many of you know, mixing Stock Solution A of Pyrocat-HD in Propylene Glycol provides stability of the stock solution on the order of years, similar to HC-110. Here is a very safe way to do this, measured for the 1000ml kit. 1. Weigh out all of the chemicals for Stock A. 50.0g of pyrocatechin, 10.0g of sodium metabisulfite, 2.0g of phenidone and 1.0g of potassium bromide. 2. Pre-heat in a water bath 750ml of propylene glycol to about 150F. 3. Add the pyrocatechin to the glycol and stir until dissolved. Should take no more than about a minute. 4. Now add the phenidone and stir. Should dissolve completely in about a minute. 5. Add the bromide and sodium metabisulfite to about 50-75ml of hot water at about 120F. Stir until completely dissolved, then mix with the propylene glycol solution. 6. Top off the solution with glycol to 1000ml Once you do this a couple of times you will find it just as easy as mixing Stock A in water. Should you be concerned about the small amount of water in the solution? Absolutely not. Pat Gainer, who is the expert on these type of solutions, has recently recommended this type of mixing for his PC-TEA formula, and if he is satisfied with the stability so am I. C. NEW PYROCAT TYPE FORMULA Since the Pyrocat-HD formula was introduced in the late 1990s I have experimented with many variations for specific purposes. For example, I added a small amount of ascorbic acid which made the formula much more active, which I called Pyrocat+. I also experimented with extra sulphite in the formula to make the formula non-staining. Most of the notes of these experiments were sent to the AZO forum. However, over the past six months I embarked on a different path of experimentation with the Pyrocat-HD formula and have recently come up with something that I consider an entirely new developer. It involves the use of a regenerative reducer other than phenidone, and the use of another restrainer. The new formula is not better than Pyrocat-HD, but it is different in a number of ways. I have done a lot of sensitometric testing of this formula and know it can do in terms of EFS and curve with a number of films. However, evaluating grain and sharpness is a highly subjective action, and for that reason I am looking for 3rd party comments. I know that there area a number of long-time Pyrocat-HD users on this forum. For those interested I would like to send you a 100ml bottle of the modified Stock A, which I will call for the moment Pyrocat2, for your evaluation. You can use your regular Stock B solution with this formula. I am primarily interested in personal feedback on results, but anyone who tests the variation should feel free to express their opinion here or elsewhere about it. OK, if interested please contact me off list, at email@example.com. I am primarily interested in current users of Pyrocat-HD, since these are the persons who could offer a good opinion of the new formula compared to the old Sandy.