You should always base your process time on the latest information available for your usual developer. Then be prepared to use these figures as a guide or starting point. You should check each set of negatives carefully, if they are starting to look dark/dense then you will need to adjust the process time by say twenty per cent. If they are looking thin/light then a slight increase in process time is needed. It is a good idea to stick to one make of developer and film until you understand what it is capable of. By doing so, you will be able to extract every detail from the negative that was originally captured. With experience comes knowledge.
Monday, 12 December 2011
The keeping qualities of photographic chemicals to a degree is dependent on the dilution of the mix. In the first instance you should always follow the manufactures recommendation when mixing stock solutions by only adding the chemical to that quantity of water thus giving you a known starting point. If you require a more dilute working developer you should only make this up just before you are about to use it. Once used it should be discarded.
Reusable developers are poured back into their containers when finished with. Each time you pour it back a little bit is used up, it is a good idea to keep these containers full to stop the developer going off. This can be achieved in several ways if it is a plastic bottle you can squeeze the air out just before you nip the cap up, add glass marbles to the bottle so increasing its level, use a concertina bottle or the plastic bag out of a wine box ( if using one of these make sure it has been thoroughly cleaned.)
Remember that developer that has been used is likely to go off more quickly. It is a good idea to keep a record on each bottle of how many film or prints and what format has been developed. When you think you have reached the maximum usage discard it and make a fresh batch.