Caught in the Web Pt 3

This is how I do my solution mixing and processing. Some members may disagree on certain points but I have been getting pleasing and consistent results for many years.

WEIGHING AND MIXING.
It is a good idea to have the formulae for all the solutions on one sheet of paper in a plastic sleeve so that individual items may be ticked off as they are added to the graduate or whatever. First place all the items for First Developer in a row and in correct order. Use only filtered water at the right temperature, which is generally recommended as 30 to 40C, and it's best to have the temp nearer 40C. For some years I used an active carbon filter which attached to the tap but I now use a Waymaster Chrystal Filter Jug (obtainable from Boots etc.). I put about 400ml of water into a 600ml graduate and stand it on a battery operated LPL Agitator. The small magnet placed in the graduate is rotated to thoroughly mix the solution while the next ingredient is being weighed. I use a Russian chemical balance to weigh quantities of less than 10 grams and place small plastic weighing boats, (obtainable from TFM), on each pan of the chemical balance. Rather than fiddle with the adjusting weights at the ends of the balance arms, I obtain true balance by placing small bits of paper on the left hand pan till the needle is centralised. Weights are then place in the left pan, and chemical in the boat on the right pan.

For quantities of 10 grams or more I use a letter-type scale with a large dial, and spoon the chemical into a plastic yoghourt container. An adjusting knob re-centralizes the needle after the empty container is placed on the scale. This scale is sufficiently accurate for the larger quantities.

After all the ingredients have been added and completely dissolved, the solution is poured through a special strainer funnel into a one litre bottle and the bottle is topped up with filtered water to the litre mark. In the case of the two developers, these are transferred to three 300ml bottles, which in fact hold 330ml each. If you have no suitable bottles they are obtainable from Boots. The advantage here is that one or two bottles may be left unused if there are only one or two films to be processed, since the unused bottles will have an extended shelf life. An alternative method of extending shelf life is to add the developing agent (Phenidone, CD3 or whatever) to the solutions just 24 hours before use. Some members however think that a developer needs to mature for three or four days for highest quality results.

It is very important to label clearly all bottles, containers and their caps, to minimise any possibility of error or cross contamination. CPI pH Meter (obtained through CRC) is used to check that each solution is within its tolerance for pH. The meter is checked by first standing it in fresh tap water, then filtered water, though ideally a buffered solution of known pH would be preferable. An unexpected pH will indicate that mistake has been made.

Finally it's a good idea to keep records in a note book of when the solutions were made up and how many films have passed through them. Also, a stock list will tell you when you need to write to Ron Croad for supplies!