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  1. #1

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    A (Pa)rodinal calculator

    Hi All,

    For those interested in making parodinal using paracetamol, see if the attached calculator is of any use, and give me feedback.

    Kind regards,
    dorff
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  2. #2

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    As background (and to prove that it works) follow this thread:
    http://www.apug.org/forums/forum37/1...e-insight.html

    Sorry, didn't check how the Instructions sheet displays in Windows - I worked from Mac. So just for clarity here are the instructions again if you need to print them out.

    This calculator aims to achieve a 4-aminophenol developer with composition similar to commercial and home-made Rodinal formulas. To use this calculator follow these instructions:

    Enter the volume of Rodinal concentrate to be generated.
    Enter the feed material quantities. These may consist of any combination of:
    Paracetamol
    4-Aminophenol
    Potassium hydroxide
    Sodium hydroxide
    Potassium sulphite
    Sodium sulphite
    Potassium metabisulphite
    Sodium metabisulphite

    The spreadsheet will calculate the final product composition. Compare the values obtained with the target values, and adjust the starting quantities until they match well (within 0,5%). Start with the paracetamol or aminophenol, then the sulphite next, and finally adjust the hydroxide. For the Na/K ratio, the target value is at or below 2. This is to prevent precipitation due to the lower solubility of sodium salts. Please follow proper safety precautions when working with chemicals. Always add reactive chemicals to water, not the other way around. Wear gloves and goggles when working with hazardous chemicals.

    Divide the water volume in two parts, starting with 20% less than the volume of developer required. Add the sulphite to one part, then the hydroxide and aminophenol to the other part. Use the sulphite part to flush the other container and recover all active developer. If any solids remain undissolved, transfer them to the final storage container. Then top up with water to the required volume. The storage container must seal air-tight. Use developing times and dilutions as for Rodinal (Massive Dev Chart). Use 1:25 and 1:50 dilutions.

    Edit: If you have a finite quantity of paracetamol and want to make the maximum volume of parodinal it can do, start by entering the paracetamol quantity, then adjust the volume until 4-aminophenol is at the target value. Follow the rest of the procedure as above and you should be fine.

    If it is not clear from the above, then here it is again: Do not use sodium-based chemicals for both the hydroxide and sulphite (whether metabisulphite or plain) - you WILL NOT get enough of everything into solution. I recommend to use potassium hydroxide and sodium sulphite, but sodium hydroxide and potassium sulphite or metabisulphite will also be okay.

    PM me if you have questions and improvement suggestions for the calculator. If I get enough positive feedback, I'll develop similar calculators for the various caffenol formulas, and anything else that is often used. Please also post samples in this thread if you wish.

    Good luck,
    dorff



 

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