Here's a good one for you...

[Vilk]

Why do the instructions for D-76, ID-11 and probably dozens of other concoctions always say to dissolve in 700 or 750 ml, then fill up to 1 litre?

Don't laugh--it took me 34 years of darkroom work to come up with this one... :confused:

 

[MattKing]

Why do the instructions for D-76, ID-11 and probably dozens of other concoctions always say to dissolve in 700 or 750 ml, then fill up to 1 litre?

Don't laugh--it took me 34 years of darkroom work to come up with this one... :confused:

When you add the powder to the water, the volume changes.

So it is more accurate to put the water in in two stages.

 

[snapguy]

anybody

If it was easy, anybody could do it.

 

[Kawaiithulhu]

Basic lab rat stuff. It's easier to say that than expect people to be able to handle "dissolve in 937.34ml" without freaking out.

 

[Bill Burk]

I find that when I used to filter as I mixed, that there were some slivers of chemical that would never dissolve...

They seemed to always dissolve in fresh water, interestingly, about as much as it took to bring the volume up to 1 gallon.

 

[Gerald C Koch]

When you dissolve a solid in water the volume usually increases. So to avoid having more volume than anticipated you start with less water, dissolve the solid and make the volume up to the specifieded volume. Interestingly this does not work with liquids. Mix a liter of water and a liter of ethyl alcohol and you get less than 2 liters of mixture.

 

[Rudeofus]

I find that when I used to filter as I mixed, that there were some slivers of chemical that would never dissolve...

They seemed to always dissolve in fresh water, interestingly, about as much as it took to bring the volume up to 1 gallon.

That was probably Metol, which dissolves quickly in neutral or acidic environment, but extremely slowly in caustic environment. These powders are coated such that the compounds dissolve in the right order. If you deviate too much from the mixing instructions (or if your water deviates too much from what the maker expected), then you will have problems dissolving all the developer ingredients. Luckily, you found a way to do it anyway.

 

[Vilk]

omnibus gratias ago

 

[F4user]

When you dissolve a solid in water the volume usually increases. So to avoid having more volume than anticipated you start with less water, dissolve the solid and make the volume up to the specifieded volume. Interestingly this does not work with liquids. Mix a liter of water and a liter of ethyl alcohol and you get less than 2 liters of mixture.

Yessir. Mix a liter of water with 1 liter of any sort of alcohol and you get most of time 1 liter of water. Why spoil a good whiskey with water ?

I never bother with precise 1 liter barrier with 0.001 % precision. For fixing and bleach solution is waste of time, after first roll of film the solution is like a dilute solution until you add refresher and even after that the solution is far away than ideal.
For developer is the same. I don' t think that more 10ml of water will spoil the solution. After years of practice anybody can put precise amount of water from start.
Ok. the developer need more attention but i find is not so critical. More critical is exposure time and for slides that is crucial.

I remember from my highschool time I had extremely underexposed negatives and I processed the paper with an extreme procedure like hot concentrate developer ~50°C and working time just enough to pass paper into solution.. around 0.5 seconds.
Did you think precise 1liter dosage will help ? 1 liter dosage is for reproductibility not for art.

 

[PeterB]

Don't laugh--it took me 34 years of darkroom work to come up with this one... :confused:

Tell us you weren't thinking about it for that long.
Not to make you feel inadequate, but it might have taken some posters here less than 34 (or
even<3.4)seconds to figure that out.

 

[Vilk]

Tell us you weren't thinking about it for that long.
Not to make you feel inadequate, but it might have taken some posters here less than 34 (or
even<3.4)seconds to figure that out.

satis longum habeo, non queror...