Homebrew wetting agent?

[Photo Engineer]

Fungi can be killed by Silver in B&W films and by Formaldehyde or other "final rinse products" in color films.

PE

 

[Agulliver]

To be clear, IPA = isopropyl alcohol and not India Pale Ale?

Oh damn. But....there is now a beer designed to process film too. Two of my hobbies rolled into one.

As PE says fungi and even bacteria should be warded off by silver in B&W films. Ergo the socks you can buy with "nanoparticles" of silver or silver compounds, to keep your feet fresh without washing your socks. YMMV, my feet are always too hot and wearing the same pair of socks two days in a row without washing said socks is NOT an option for me.

 

[Ian Grant]

To be clear, IPA = isopropyl alcohol and not India Pale Ale?

Ideally you use both, the Isopropyl alcohol in the wetting agent and the India Pale Ale in a pint glass as refreshment after another successful batch of negatives is hung to dry ;D. My particular current recommendation is "Proper Job" a Cornish IPA . . . . . . . . . don't drink while processing !

Ian

 

[Rudeofus]

Can someone explain to me, why there should be Isopropylalcohol or similar in a final rinse?

 

[Ian Grant]

Alcohol is in wetting agents used to pre-soak films as it helps prevent air bells, it may also help prevent foaming, Traces of wetting agents are often added to developers, Alcohol can also be used in developers instead of wetting agents to help prevent air bells and it also helps prevent some precipitation in concentrated developers.

Wetting agents can also be found in powder form, which is how they are added to powder developers.

Ian

 

[ruilourosa]

i do not know what are the anti fungi and anti bacterial adittives put in tetenal mirasol... but that could be a lead...

 

[Rudeofus]

There's an MSDS on Tetenal's web page.

Fun fact: If you search for Mirasol on their web page, they offer MSDS for two different package sizes: 250ml and 20l. The MSDS link for 250ml points provides the MSDS for Ilford Ilfotol. I wonder whether these two are identical.

 

[GLS]

I had been using Ilfotol in distilled water as a final rinse, but would occasionally still get drying marks. I eventually got fed up of this and have just switched to a 50:1 mixture of distilled water/IPA as a final rinse/soak. Works extremely well, leaving no residues, and the film dries faster.

 

[Rudeofus]

So if this IPA is the actual thing helping us with rinsing&drying the film, what's the point of this Triton-X100 or Tween 20 ingredient then? Do we really need it for B&W work? Is this the ingredient which leaves behind water marks ?

 

[GLS]

So if this IPA is the actual thing helping us with rinsing&drying the film, what's the point of this Triton-X100 or Tween 20 ingredient then? Do we really need it for B&W work? Is this the ingredient which leaves behind water marks ?

IPA isn't the only choice of wetting agent (or surfactant), nor is it unique in its action. Many other organic solvents could be equally suitable for the task, provided they are miscible with water and lower the surface tension of the mixture. IPA is just a good choice as it cheap, relatively non-toxic and has a relatively low boiling point (and hence promotes more rapid drying).

The other two products you mention act as wetting agents in the same way (i.e. they lower the surface tension of the water), but they additionally can act as detergents, which could be advantageous if you are using hard water (rather than soft, or better yet distilled water in the final rinse). However they are not volatile materials, so can leave residues when dried. IPA on the other hand (or another low boiling point organic solvent) will not leave any residues behind on evaporation, provided it is of a high purity.

As I use two separate distilled water washes at the end of my wash cycle (the last one containing the IPA), I have no need of any detergent properties; hence the IPA is enough. Hell, I could just use distilled water on its own, but it takes longer to dry and can cause more curling.

 

[Rudeofus]

So in other words the best home brew final rinse for black&white would be 100 ml IPA plus 900 ml deionized water, and I would never end up with drying marks on my film ever again?

Wow! This simple recipe solves a problem, that many have reported here and elsewhere, and which no commercial product has ever solved ...

 

[Photo Engineer]

I remind you all again that some versions of IPA contain a water incompatible denaturing agent that can leave a scum on film. IPA is NOT a wetting agent. Wetting agents have long chains of carbon atoms in them, but IPA only has 3.

Just be aware and test IPA for the incompatible material before you use it.

PE

 

[GLS]

I remind you all again that some versions of IPA contain a water incompatible denaturing agent that can leave a scum on film. IPA is NOT a wetting agent. Wetting agents have long chains of carbon atoms in them, but IPA only has 3.

I qualified that the IPA should be pure. I use 99.9% grade.

I'm afraid your second point is incorrect. The definition of a wetting agent is anything which lowers the surface tension of the liquid it is dissolved in, and IPA most assuredly does do this to water. Your idea that they must contain long carbon chains is more relevant to potential detergent properties of the surfactant (the classic situation being a polar head group, long fatty chains, formation of micelles etc).

 

[GLS]

So in other words the best home brew final rinse for black&white would be 100 ml IPA plus 900 ml deionized water, and I would never end up with drying marks on my film ever again?

Wow! This simple recipe solves a problem, that many have reported here and elsewhere, and which no commercial product has ever solved ...

A 10% mixture is higher than necessary, and would be more expensive to use, although it would also dry faster.

 

[Photo Engineer]

I qualified that the IPA should be pure. I use 99.9% grade.

I'm afraid your second point is incorrect. The definition of a wetting agent is anything which lowers the surface tension of the liquid it is dissolved in, and IPA most assuredly does do this to water. Your idea that they must contain long carbon chains is more relevant to potential detergent properties of the surfactant (the classic situation being a polar head group, long fatty chains, formation of micelles etc).

There are surfactants, wetting agents and detergents. Photo Flo is an example of a wetting agent and does fulfill my definition, which I admit was too non-specific but simpler for the audience. Sorry.

They can have positive charges, negative charges and no charge. The best have no charge, the second best have negative charges. Photo Flo and IPA have no charge. If the molecular weight is low enough, it evaporates, if high enough it forms a uniform distribution over the surface of the film, and if it is in-between, well, then it might crystallize and do "bad things".

So, while IPA can and does work, Photo Flo and the like have been found to be superior for a number of reasons. In actual fact, when we need something to reduce bubbling or foaming at Kodak, we use t-Butyl Alcohol in spray bottles, but it is not readily available and is a slush at room temperature. It is therefore useless for this current purpose and IPA (pure) is better.

You may be an expert in surfactants, IDK, but this is my thumbnail sketch from my EK experience just for the audience.

Sorry again for the bad definition. Thanks.

PE

 

[GLS]

Sorry again for the bad definition. Thanks.

PE

No problem. This is the trouble with definitions sometimes; they can get a bit fuzzy depending on the context of their use.

I would not say I am an expert on surfactants, but I am a research chemist by profession and have two degrees in chemistry, so I know a general thing or two about the subject.

I have no doubt PhotoFlo and similar products work better when using tap water, which is clearly what they were designed for, and what the vast majority of users will be doing. I am in the fortunate position to have free deionised water at my disposal, and therefore to get the final rinse job done efficiently I only really need the wetting & rapid drying properties IPA lends the water.

 

[Rudeofus]

The money spent a single roll of cheap film would pay for 10+ liters of deionized water. I have no idea why people put up with drying marks and gunk on their film just to save on deionized water. These drying marks are even there if I mix STAB with deionized water!

I took the 10% IPA number from your post "half a cup in one liter". What would be the lowest IPA concentration that works reliably ?

 

[GLS]

I took the 10% IPA number from your post "half a cup in one liter". What would be the lowest IPA concentration that works reliably ?

The half a cup comment wasn't by me.

I use approximately a 2% solution of IPA, but I'm still tinkering with the ratio. 5% I'm sure would be more than enough.

 

[jim appleyard]

I've always used Kodak's Photo-Flo. IIRC, there is some alcohol (not sure which kind) already in it. I personally don't see a need for anything else. It's incredibly cheap; a quart bottle is a 3-lifetine supply! About 5 years ago I was getting low on Photo-Flo and ordered a bottle of the Ilford brand, even less money and contains ether, another quick-dry chem. I was then given a partial bottle of Photo-Flo by someone who ws getting out of film. I still haven't opened the Ilford!

 

[MattKing]

I use Kodak Photo-flo and Isopropyl Alcohol ("IPA") as follows:
1) I mix up a stock solution - 1 part Photo-flo + 7 parts IPA;
2) at time of use, I dilute the stock 1 part stock + 24 parts tap water.
The stock keeps without things growing in it. The 1 + 24 dilution is easy to do accurately and repeatably without lab equipment or skills.
We have good, soft tap water here. If necessary, I could use either the demineralized water we buy in 18.5 litre bottles, or distilled water we can buy in 4 litre jugas.
In addition to the surfactant properties, IPA speeds drying. In the dilution I am using, there isn't much of it there.

 

[Rudeofus]

The argument was, that Photoflo/Ilfotol/... are only needed if one does final rinse with tap water. I have used Ilfotol or similar, Tetenal STAB and friends for years, and have been battling drying marks for just as long.

And I seem to be not the only one here on photrio.

 

[Agulliver]

Try buying deionised water in the UK. It's really not common. Nowhere local to me sells it at all even in small quantities. And where the phrack am I going to store it? I have a full on water still at work, producing 99.98% pure H2O at a rate of 4 litres per hour. I typically keep 50 litres at work and run the still when I have less than 30 litres to hand. I could easily bring distilled water home but I have absolutely nowhere to keep it in the quantities required. But....a 500ml bottle of wetting agent is quite convenient.

Fortunately I also have two litres of 99.9% IPA at work, and nobody is going to miss 30ml ever 18 months. So I can mix that with the distilled water and photo-flo as described above. And I can confirm that it works a treat.

 

[GLS]

Try buying deionised water in the UK. It's really not common.

Tesco, Sainsburys and Morrisons all sell it. So does Halfords, B&Q and others. 2.5 litres is typically £1.

 

[Anon Ymous]

Try buying deionised water in the UK. It's really not common. Nowhere local to me sells it at all even in small quantities...

Seriously? What do you use in a steam iron and where do you buy it? Over here, a 4-5l bottle of deionised water costs 0,8 to 1€ and you can find it at any super market. It's steam distilled water that is very rare over here.

 

[Agulliver]

I have never used anything but tap water in a steam iron. Certainly the two Tesco superstores within 20 minutes don't stock deionised water. Halfords might, though to be fair I've not looked for it. However for washing films I would need to keep several litres of the stuff. It's far more convenient to keep 500ml of wetting agent.

If I really wanted steam distilled water, I'd bring it from work. As previously mentioned I have a water still there. I live in a one bedroom "maisonette" shared with the wife. Even having a nice garden there isn't anywhere practical to be storing 5-10 litres of liquid.