If we wanted to carry out the measures to be more precise that more accurate at each temperature, my suggestion is to start thinking in terms of weight (ahem ... of "mass"), instead of volume. This is for two different reasons, both equally valid:
the first is of a scientific nature and is related to invariance of weight in relation to temperature: if we take a flacone10 g of a developer to be diluted and we put them in a glass, these will increasingly 10 g regardless of the temperature and even by the pressure to which they will be exposed (obviously, unless a part of the product to evaporate).
The second reason is of a practical nature: as much as in the laboratory and especially at home, are much more reliable instruments able to measure the weight (scales) rather than those capable of measuring the volume (graduated containers, pipettes, droppers, flasks, pumps, electronic meters of various nature, etc.).
The problem is that, unlike water, other liquids usually have a density other than 1 and usually not known a priori. How can we transform the dose of liquid required by volume in the corresponding dose by weight, vary with temperature?
Nothing easier: we take the container that we have just graduated and misuriamone the tare of a sling sensitive kitchen, one of those capable of measuring the individual grams, even better if the tenths of a gram. Then fill it up to a certain notch with the liquid to evaluate, for example up to the mark that marks the 25 ml. We measure the weight on the balance of these net 25 ml of liquid (eg. 30 g).
Dividing the weight (in grams) by the volume (in ml or cc) we obtain the density, expressed in g / ml or if preferred in g / cc, referring to that specific liquid and at the temperature of the measurement, possibly that of the environment (about 20 ° C).
Density = weight [g] / volume [ml] = 30 g / 25 ml = 1.2 g / ml
I imagine that the person who completed the instructions and rates of application of a liquid product, if not commented otherwise, intended to refer to measurable volumetric conditions at room temperature.
To obtain the weight in grams corresponding to the quantity in the volume indicated by the manufacturer (eg. 80 ml), multiplies the required volume for the density just calculated for the given liquid:
Weight [g]: volume [ml] x density [g / ml] = 80 ml x 1.2 g / ml = 96 g
Then 96 g of the liquid in question, so much in a cold winter day than on a hot summer, will be equivalent to the amount of product which is at room temperature, will correspond to a volume of 80 ml (or 80 cc) of the same liquid.
Is amusing to note that my AP tank requires 600ml developing for one 120 roll.using Rodinal/APH09/Fomadon R09 (all with SG 1.36!!) in a dilution of 1 + 50
