Tetenal 3-bath 1st developer melts "glass" pebbles

[guoming_shou1]

It is color developer. So I'm not sure if it is discussed in this B&W

forum.

 

I bought some "glass pebbles for decoration" and used them to fill my

Tetenal 3-bath 1st developer's bottle after part of the concentrate

was used. I knew those pebbles were for decoration, but anyway, they

were made of glass, and I couldn't find those made specifically for

developers. So, I enjoyed dropping them in one by one, hoping they

would keep my developer fresh for a couple of months.

 

After about 2 weeks I looked at the 1st developer. The pebbels were

melted a little bit and the concentrate was cloudy when disturbed.

(The concentrate's color is still right.) I let the concentrate rest

for sometime, and carefully poured some out to test it. I used a 120

roll of Kodak E100SW. But I couldn't tell anything bad from the test.

I thought it was reasonable as probably the power of the developer

was only used a little bit to melt the pebbles, and the

melted "glass" didn't have effect on the developing process.

 

Just to be sure, I'd like to know what would happen if the 1st

developer was bad, say, after it melts too much "glasses". Will it be

density more than color balance?

[donald_miller1]

Interesting...Wonder why it melted the glass pebbles and not the glass bottle?

[stuart_todd]

Are you sure those 'pebbles' are glass???

I know for a fact many those so-called glass decorating items are made of a cheap compound plastic, which although do feel like glass, aren�t and can be melted by some fairly common household items. A good test would be to hit one with a hammer and see if it shatters or cracks/crumbles (oh and do wear protective eyewear). If shatters like glass, its glass, if the later applies, you've got plastic. Or another trick would be to heat one of the pebbles up with a cigarette lighter. If it melts, it's plastic. Also another line of thinking is- Are the pebbles colored? It could be the dye leaching out, rather than the glass/plastic. I�ve had than happen before�

 

With regard to chemical contamination, I'm not to sure about how it would react to color chemicals (me being a black & white freak) but I put some cheap marbles into my last bottle of Microphen. Two months later I found that the little colored swirls of paint where being drawn out of the marbles and into little colored clouds around each marble at bottom of the bottle. In panic mood I siphoned off the un-effected top layer and ran a test roll of film through the standard process. No problems, film came out as per normal.

 

Personally I'd salvage as much of un-effected developer as possible, as the bottle I doubt gets moved around very much. So the melted portion should still be at the bottom of the bottle (the 'melted stuff' will have more density than the straight developer and should be at bottom of bottle. Unless the theory of gravity is different in your area...). I'd rather waste 200-300mls of developer than lose that perfect award winning shot. But hey, that's just me...

 

Stu :)

[guoming_shou1]

No, the bottle is plastic.

 

I also doubt the pebbel is not true glass. I smash one and it looked like glass, though.

 

Anyway, I'm not worried about losing a perfect shot since normally I do a test roll and then proceed with bulk developing. Of course it is also a good idea to buy a bottle of 1st developer and continue using the other of the kit.

[donald_miller1]

I seriously doubt that your pebbles are glass. Glass is by nature a far more inert material then any plastic that you encounter. It takes something akin to hydroflouric acid to even etch it, let alone melt it. I don't know of any alkaline compound that has enough activity to melt glass (silica). Most developers that I have encountered are alkaline or in some cases solvent based compounds. I would be very suspect of your developer, especially in light of your comment about an important negative. Whatever it was that melted, would have joined to the chemical compound that your first developer is comprised of. Possibly and most probably forming a new chemical compound.

[eric_chamberlain]

There are very few polymers that have nearly the same optical quality and brittleness as silica glass. Two of these are polycarbonate and acrylic. Speaking in terms of specific gravity acrylic and polycarbonate are much lighter than glass (1.15 and 1.10 compared to 2.21). All three will sink in water solutions (a developer) but only glass (of these three materials) will sink in a solution of 1.2 specific gravity. This solution can be made with table salt and water.

 

In my current days of fluid mechanics, I recall that specific gravity is the density divided by 1000. So to reach an SG of 1.2 you would have to dissolve 449g of table salt (SG of 2.165) into a liter of water. Which would probably require boiling.

 

Yes this sounds impractical but it would be a fairly absolute way of determining if these marbles are glass or not.

 

I agree on the chemical inertness of glass. The high melting temp of glass also sheds light on the reactivity of a chemical required to react with it. Mostly around the strength of hydroflouric acid.

 

Thoughts of a scientifically grounded guy.....

[guoming_shou1]

Actually my unergraduate major was Chemical Engineering. I totally agree about the property of glass, and how to test if a pebble is truely made of glass.

 

Maybe I'll let the pebbles to melt for a couple of months, and then do a side-by-side comparison with fresh Tetenal. Let's see what will happen. My guess is if there is bad thing, it should be very similar to what over diluted developer can cause. According to Tetenal manual, the diluted chemical can be reused. So there is some safe margin. If the amount of power the developer uses to melt the pebbles is within that margin, then it will still do an adequate job.

[ole_tjugen]

Melted or etched?

 

The reason for keeping (many) developers in plastic bottles is that they are alkaline enough to etch most glasses. Of course there is a risk that developers will oxidize more rapidly in plastic bottles, but there are very good low-permeability bottles to be found. Note that most commercial developer concentrates are sold in plastic bottles. This is not only dye to cost and weight, but many of those concentrates will dissolve glass...