Target PH for film Developer and Paper Dev

haryanto

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anybody know what the right PH for film developer (ie. Pyrocat MC) and paper developer (ie. Ansco 120), is there any rule of thumb for this,

I measure my pyrocat mc, is about 10,
and ansco 120 about 11

many thanks for reply
 

sanking

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haryanto said:
anybody know what the right PH for film developer (ie. Pyrocat MC) and paper developer (ie. Ansco 120), is there any rule of thumb for this,

I measure my pyrocat mc, is about 10,
and ansco 120 about 11

many thanks for reply
Click to expand...

Your pH meter is slighly off. The working pH for Pyrocat-MC should be between 10.5 - 10.9.

I don't know about Ansco 120.

Sandy King
 
OP
OP

haryanto

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sanking said:
Your pH meter is slighly off. The working pH for Pyrocat-MC should be between 10.5 - 10.9.

I don't know about Ansco 120.

Sandy King
Click to expand...

I use PH Indicator paperits not very accurate I think

thanks Sandy
 

Photo Engineer

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As pH goes up, contrast generally goes up.

Paper developers generally are lower in pH than film developers.

This generalization is like all generalizations, just a general rule, not an absolute.

PE
 

Keith Tapscott.

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Photo Engineer said:
As pH goes up, contrast generally goes up.

Paper developers generally are lower in pH than film developers.

This generalization is like all generalizations, just a general rule, not an absolute.

PE
Click to expand...
I`m not a photo-chemist, but I would have thought it would be the other way around. e.g. D-76 (Borax buffered) would have a lower pH than D-72 or Dektol.:confused:
 

Photo Engineer

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Not necessarily. Borax buffered developers with pH 10 or 11 were used in the 50s and 60s for color films.

In any event, what I said was a generalization, not a hard and fast rule.

There are many low pH film developers.

However, developers such as Dektol are at about 10.5 while D-19 and D-8 and D-11 are higher in pH and are film developers. There are many many more examples like this going round in my head. BTW, these film developers are also higher in contrast, and so validates both generalizations.

Please don't generalize my generalizations. I'm just giving a rule of thumb, that there are more high pH film developers than paper developers, and more high pH high contrast developers.

There are exceptions to every "rule".

PE
 
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