Personally, while it is possible to reuse chemicals, I don't for consistency reasons. If, for example you are using Multigrade Dev at 1:4, that's only 4ml of Dev per syringe, which isn't much to start with, and even less active component on subsequent prints when you take into account the amount of liquid absorbed by the emulsion, and used during development.
However you are more likely to get favourable results, if the prints are light/high key so the developer has less work to do (but the Fixer will have more work to do, especially when the amount of Dev carried over for mutiple prints is taken into account). Both exhausted Developer and Fixer can cause staining.
Given a syringe is only 20ml (22ml if you pull it the the max), I use fresh chemical each print each time, but I have on occasion reused 2 or 3 times when I was travelling light and only carried a very small amount of chemicals, topping up the small amount lost. If I lost more than a few ml of Dev, I would use fresh Fix the next time. By the 3rd time, the Dev looked pretty bad, so I don't consider this to be worthwhile, given the cost of the paper vs the cost of the chemicals.
I don't know if anyone has produced a table for extended develment times, but if you look at Ilford's Simply Range for reusing 600ml of Dev for 2 x 500ml processes, it is to use 500ml the first time, remix with the remaining 100ml, and use 500ml and extend by Dev times by 10%.
So if you want to try that, top up, extend times, and observe the results.
Personally, while it is possible to reuse chemicals, I don't for consistency reasons. If, for example you are using Multigrade Dev at 1:4, that's only 4ml of Dev per syringe, which isn't much to start with, and even less active component on subsequent prints when you take into account the amount of liquid absorbed by the emulsion, and used during development.
However you are more likely to get favourable results, if the prints are light/high key so the developer has less work to do (but the Fixer will have more work to do, especially when the amount of Dev carried over for mutiple prints is taken into account). Both exhausted Developer and Fixer can cause staining.
Given a syringe is only 20ml (22ml if you pull it the the max), I use fresh chemical each print each time, but I have on occasion reused 2 or 3 times when I was travelling light and only carried a very small amount of chemicals, topping up the small amount lost. If I lost more than a few ml of Dev, I would use fresh Fix the next time. By the 3rd time, the Dev looked pretty bad, so I don't consider this to be worthwhile, given the cost of the paper vs the cost of the chemicals.
I don't know if anyone has produced a table for extended develment times, but if you look at Ilford's Simply Range for reusing 600ml of Dev for 2 x 500ml processes, it is to use 500ml the first time, remix with the remaining 100ml, and use 500ml and extend by Dev times by 10%.
So if you want to try that, top up, extend times, and observe the results.