Light sensitivity of darkroom chemicals?? *confused*

Hi everyone! I'm a bit confused about whether I can mix the chemicals

in full light or not? I'm assuming I can, as measuring temperature

and quantities is necessary, but I read somewhere that the chemicals

should be stored in light-tight containers because some are sensitive

to light. Can someone clear this up for me?

Thanks,

Mel

The most sensitive and fugitive of your chemnicals is the developer, and the enemy is oxygen far more than light.

Sure you can mix the stuff up in full light. No problem there. Just take some reasonable precautions like not storing the chemicals on a windowsill or something like that and you 'll be fine. Brown bottles are for the most part, unnecessary.

The earlier comment is right, but perhaps I can shed a little more "light".

 

Oxygen will deplete the diluted developer within hours, depending on temperature. However, if you store diluted developer in transparent bottles, with most of the air excluded, light will destroy the diluted developer in hours to days - again depending on temperature.

 

Other chemicals, fixer, stop, etc. aren't so sensitive - and concentrated chemicals last a lot longer, usually months. (See the manufacturer's instructions for details.)

 

So, you can certainly mix your developer and otherv chemistry in the light, but use the developer promptly - and don't shake it up!

 

Have Fun!

I mix my stuff under a 150w bulb, I like to see what I am doing sometimes. I process the film in the kitchen often in daylight (the tank is light proof). I store all my chemicals in white plastic containers, most of the time the darkroom is just that, dark so no problem. If you can find a good source of cheap distilled water then mix your chemicals with it. With pure water dilluted chemicals will keep much much longer.

Melissa..anything that I've used can be mixed in room light (excepting Liquid Light of coarse).<p>I want to comment on mixing developers...it's best to go by manufacturers recommendations. Some developers--for example XTOL or HC110 can be mixed and used for weeks--they are so stable that they are used in replenishment systems where the developer can be a 6 months old--more replenisher is just added to it as it's used. Something like Rodinal (who's stock may last decades)once mixed must be used.<p>I guess this topic is like everything else in photography...testing, using your methodology, is the only way to REALLY know.

thanks very much for clearing that all up for me, everyone! Much better.

Mel

<i>"XTOL or HC110 can be mixed and used for weeks--they are so stable that they are used in replenishment systems where the developer can be a 6 months old--more replenisher is just added to it as it's used. Something like Rodinal (who's stock may last decades)once mixed must be used."</i></p>

 

This is somewhat misleading. The confusion is that Kodak uses a 3-tier method of storing chemicals:</p>

 

- liquid concentrate (like HC-110). This does not apply to powders.<br>

- stock solution (an intermediate dilution of liquid concentrates, or the first solution used for powders)<br>

- working solution (the final dilution used for development, when the developer is not used �straight�)</p>

 

Rodinal only uses:</p>

 

- liquid concentrate<br>

- working solution</p>

 

For all developers, if the working solution (including HC-110 and XTOL) is a dilution of the stock solution, it should be used relatively soon after mixing. Stock solutions can be stored for longer periods (if applicable).</p>