Hi all,
While comparing different developers Im trying to understand how the different chemicals in the developer affects the end result. Note that this is for reversal developing Tmax400, however Im assuming som universality.
These days Im comparing Ilford PQ Universal with a Orwo recipe where Im using Metol instead of Phenidone. The one liter working solution of PQ is as follows (for the second development this was diluted to a little stronger then half strength):
Phenidone 0,2
Sodium Sulphite (anh) 21
Hydroquinone 5
Potassium Carbonate 16
Sodium Hydroxide 0,9
Potassium Promide 0,8
Benzo xg
And the one liter working solution of the Orwo recipe is as follows (same for both 1st and 2nd development):
Metol - 2g
Sodium sulphite (anh) - 25g
Hydroquinone - 10g
Sodium carbonate (anh) - 20g
Potassium bromide - 6g
Sodium hydroxide - 5g
Results:
PQ gives more 'glow' and volume or depth, they are also warmer.
Orwo gives sharper positives with more clarity.
Id be interested to know which chemicals are causing these different charecteristics.
As far as I understand Potassium Carbonate gives warmer results then Sodium Carbonate, so I assume using that in the Orwo recipe could produce warmer positives. But is it then possible to predict negative side effects, ie a loss of sharpness?
Ilford also seem to advise to increase the content of potassium bromide to get warmer results (http://lostlabours.co.uk/photography/formulae/developers/dev_cool_wam_tones.htm). However, there is a lot more potassium bromide in the Orwo recipe then the PQ recipe.... Im assuming the Sodium Hydroxide is neutralizing it?
I know that toning is also an option but Id like to know how the different chemicals can be adjustet to get a spesific end result. Is it possible to identify why these two developers gives the resullts they give based on their content? Clearly Id like what both developers provide combined.
Cheers
Peter
While comparing different developers Im trying to understand how the different chemicals in the developer affects the end result. Note that this is for reversal developing Tmax400, however Im assuming som universality.
These days Im comparing Ilford PQ Universal with a Orwo recipe where Im using Metol instead of Phenidone. The one liter working solution of PQ is as follows (for the second development this was diluted to a little stronger then half strength):
Phenidone 0,2
Sodium Sulphite (anh) 21
Hydroquinone 5
Potassium Carbonate 16
Sodium Hydroxide 0,9
Potassium Promide 0,8
Benzo xg
And the one liter working solution of the Orwo recipe is as follows (same for both 1st and 2nd development):
Metol - 2g
Sodium sulphite (anh) - 25g
Hydroquinone - 10g
Sodium carbonate (anh) - 20g
Potassium bromide - 6g
Sodium hydroxide - 5g
Results:
PQ gives more 'glow' and volume or depth, they are also warmer.
Orwo gives sharper positives with more clarity.
Id be interested to know which chemicals are causing these different charecteristics.
As far as I understand Potassium Carbonate gives warmer results then Sodium Carbonate, so I assume using that in the Orwo recipe could produce warmer positives. But is it then possible to predict negative side effects, ie a loss of sharpness?
Ilford also seem to advise to increase the content of potassium bromide to get warmer results (http://lostlabours.co.uk/photography/formulae/developers/dev_cool_wam_tones.htm). However, there is a lot more potassium bromide in the Orwo recipe then the PQ recipe.... Im assuming the Sodium Hydroxide is neutralizing it?
I know that toning is also an option but Id like to know how the different chemicals can be adjustet to get a spesific end result. Is it possible to identify why these two developers gives the resullts they give based on their content? Clearly Id like what both developers provide combined.
Cheers
Peter