Question About Wetting Agents

bvy · Oct 20, 2016

Quick question: After soaking film in a wetting agent for the prescribed amount of time and hanging it to dry, should I see water beading up on the film? Or should it appear as a uniform wet surface?

There was a drying mark or two on the last batch of HP5+ (35mm) that I developed. It appeared as an elongated U in the direction the film was hanging. I'm using Edwal LFN. I had been using one drop per 500ml of water; tonight, I used one drop to 250ml to see if that makes a difference, but I still see beads of water sitting on the film. The directions call for 2 drops per 16 oz. of tap water, and 1 drop per 16 oz. of distilled water. I ALWAYS use distilled water. My last rinse cycle before the wetting agent is also in distilled water.

Thanks.

obviouslygene · Oct 20, 2016

depends on wetting agents. some people squeegee their films, either with a squeegee or a tool.
i use fujifilm driwell, there are specific instructions to only sit it in for 30s and NEVER squeegee.

Truzi · Oct 20, 2016

When I used the recommended amount of surfactant, I ended up with a film on my dry negatives, so I began using less, but this didn't totally remedy the issue of drying marks.

Now, when I remove the reels, I place them on a paper towel for a few minutes so the water has a shorter distance to "flow," and goes towards the edges. Then I remove the film and hang to dry. Some will hang the film diagonally for similar reasons.

Leigh B · Oct 20, 2016

I run the film between my first and middle fingers (well-washed) to remove any significant surface water.

Never had a water spot problem.

- Leigh

Gerald C Koch · Oct 20, 2016

I have never had any problems with Kodak Photo-Flo. However I use it very sparingly 2 to 4 drops for 250 ml of water. I plan on leaving it in my Will. I went to the local pharmacy and bought a dropping bottle whose cap perfectly fits the Photo-Flo bottle. I never touch the film emulsion with anything -- squeegees, sponges, or fingers.

The problem with Photo-Flo leaving a greasy residue that some people experience can be traced to the antifoaming agent present in the mixture. When mixed without this chemical and only the surfactant Triton X-100 there is no problem. Kodak uses it to prevent foaming in processing equipment. The home user doesn't really need it.

Very hard water can also cause drying marks. If you live in such a locality it is best to use distilled water to mix the surfactant either Photo-Flo or LFN.

Doremus Scudder · Oct 21, 2016

The object of using a wetting agent/surfactant on film is to break up the surface tension of the water so that water does not bead up. If it does, you are using too little surfactant or your product is contaminated/inferior. Water should form a sheet and/or any drops should easily run off the film. I've had no problems with Kodak PhotoFlo when used as directed.

If you have hard water, extend your final rinse in wetting agent/distilled water to allow time for the minerals to diffuse out into the solution. This will prevent drying marks due to mineral accumulation. Don't save and reuse your wetting agent; use it "one-batch."

Best,

Doremus

pdeeh · Oct 21, 2016

bvy said:
. The directions call for 2 drops per 16 oz. of tap water, and 1 drop per 16 oz. of distilled water.

I can't help wondering why you're choosing to ignore the manufacturer's instructions.

I had endless problems with drying marks using Ilfotol, following all the suggestions "on the internet" about using drips and drops and ignoring what Ilford themselves said.

Then with stunning originality I decided to follow the dilution instructions on the label, and Lo! I never had drying marks again, whether I use distilled, deionised or indeed my own nasty chalky tap water.

Suggestion: Try 2 drops, report back

Svenedin · Oct 21, 2016

I find that giving the film a few vigorous flicks whilst still on the reel helps remove a lot of water. You have to make sure you have your finger over the end of the film to prevent it coming out of the reel. I use Tetenal Mirasol and distilled water for the final rinse. Mirasol is an anti static agent as well as a wetting agent.

jonasfj · Oct 21, 2016

The wetting agent contain a surface active ingredient the reduces surface tension of the rinse water. This prevents formation of droplets on the surface of the film. It basically is dish soap without color agents and scent.

If the wetting agent is working as it is supposed to, there should be no visible droplets on the surface of the film.

The action of the wetting agent is instant, so no need to wait for several minutes.

Obviously it is a good idea to follow the manufacturer's instruction regarding concentration. I think it is safe to assume that they have been testing their product. I use Ilfotol and have never had a problem with the recommended dilution.

If you use a wetting agent and you hang the film to dry vertically, there is no need to wipe the excess rinse off. However, since I have little patience and want the film to dry asap, I usually wipe the film between two fingers. I have had bad experience using a squeegee so I don't, but it seems like a lot of people like it.

Another advice is to use de-mineralized water in the final rinse. I make my own by simply boiling water and filtering off the solids that precipitate during cooling.

Good luck!

Jonas

Rick A · Oct 21, 2016

bvy said:
Quick question: After soaking film in a wetting agent for the prescribed amount of time and hanging it to dry, should I see water beading up on the film? Or should it appear as a uniform wet surface?

There was a drying mark or two on the last batch of HP5+ (35mm) that I developed. It appeared as an elongated U in the direction the film was hanging. I'm using Edwal LFN. I had been using one drop per 500ml of water; tonight, I used one drop to 250ml to see if that makes a difference, but I still see beads of water sitting on the film. The directions call for 2 drops per 16 oz. of tap water, and 1 drop per 16 oz. of distilled water. I ALWAYS use distilled water. My last rinse cycle before the wetting agent is also in distilled water.

Thanks.

Use the recommended mix, but add one capfull of 91% isopropyl alcohol to it, soak for at least one minute, then shake off the excess liquid from the film before hanging. I have never seen water beading nor drying marks on any of my films with this method in all the years I've been using LFN. I switched to LFN in the mid 80's after much frustration with Photo-Flo

bvy · Oct 21, 2016

Thanks everyone. First of all, I'm using DISTILLED water. Sorry -- I thought I said that. Second, I do give the reel several good shakes to remove as much excess water as possible before hanging. I use SS reels, so the film is on their pretty securely.

I could add alcohol to the mix; I have the 99% stuff here. But I feel like I'm making this more complicated than it needs to be.

pdeeh said:
I can't help wondering why you're choosing to ignore the manufacturer's instructions.

How did you arrive at that? I said I started with 1 drop per 500ml (~16oz.) of distilled water, which is the prescribed amount. With that still causing issues, I simply used their recommendation for tap water -- 2 drops per 500ml = 1 drop per 250ml. I haven't looked closely at the film yet, but...

If water should not bead up on the film, then something's wrong. I mix the rinse fresh and use it one shot, and it's a new bottle. Since it's a squeeze bottle (and I'm careful!), nothing could have realistically contaminated it. Even with the 1/250 dilution, small beads of water were visible.

Svenedin · Oct 21, 2016

Maybe try another drop next time and keep on increasing by one drop until it works or switch to a different product.

Rick A · Oct 21, 2016

The alcohol helps the film dry faster, helps sheet the water off. Years ago I had read that adding alcohol helps speed things up, there are others here that do likewise.

MattKing · Oct 21, 2016

I add alcohol, but mostly for a different purpose.

I think a lot of the problems with wetting agents arise from the fact that using drops to measure how much concentrate is added is imprecise.

I use alcohol to make up a stock solution (1 part Photo-flo concentrate + 7 parts decent quality isopropyl alcohol). That stock solution is then diluted for use 1 part stock + 24 parts water. It is easy to reliably and repeatably measure 20 ml of stock solution and then dilute it 1 + 24 (giving 500 ml of working solution at a 1:200 dilution). It is far more difficult to reliably and repeatably measure 2 ml of stock solution and then dilute it 1 + 199 (also giving 500 ml of working solution at a 1:200 dilution).

The reason for using alcohol rather than water to make up the stock solution? If you use water, mould grows quickly in the stock solution, whereas you can safely store the alcohol based stock.
The film probably dries slightly faster too.

bvy · Oct 22, 2016

To follow up, the film that I processed and dried using Edwal LFN, 1 drop/250ml water, also showed a few drying marks, though I really had to look for them. The water still beaded up on the film, in the same manner as the 1/500 dilution, which I wasn't happy to see -- at least if that means drying marks, which I think it does.

Today, I went back to Photo-Flo at the recommended dilution -- 2ml/400ml water or 1+200 since we're dealing with the same unit of measure again. I could see water moving off the film at the very bottom (hung vertically) but for the most part, the film was a uniform wet surface with no discrete beads of water showing anywhere. We'll see if that translates to no drying marks...

Sirius Glass · Oct 22, 2016

bvy said:
Today, I went back to Photo-Flo at the recommended dilution -- 2ml/400ml water or 1+200 since we're dealing with the same unit of measure again. I could see water moving off the film at the very bottom (hung vertically) but for the most part, the film was a uniform wet surface with no discrete beads of water showing anywhere. We'll see if that translates to no drying marks...

That is the result that I get when I use PhotoFlo at 2ml/400ml water or 1+200. No wiping and no squeegees.

mshchem · Oct 22, 2016

jonasfj said:
The wetting agent contain a surface active ingredient the reduces surface tension of the rinse water. This prevents formation of droplets on the surface of the film. It basically is dish soap without color agents and scent.

If the wetting agent is working as it is supposed to, there should be no visible droplets on the surface of the film.

The action of the wetting agent is instant, so no need to wait for several minutes.

Obviously it is a good idea to follow the manufacturer's instruction regarding concentration. I think it is safe to assume that they have been testing their product. I use Ilfotol and have never had a problem with the recommended dilution.

If you use a wetting agent and you hang the film to dry vertically, there is no need to wipe the excess rinse off. However, since I have little patience and want the film to dry asap, I usually wipe the film between two fingers. I have had bad experience using a squeegee so I don't, but it seems like a lot of people like it.

Another advice is to use de-mineralized water in the final rinse. I make my own by simply boiling water and filtering off the solids that precipitate during cooling.

Good luck!

Jonas

You are not demineralizing water by boiling it. In fact you are vaporizing pure water as steam. You are actually increasing the concentration of dissolved solids. When the water cools in the pan the reduced water volume is insufficient to keep all the solids in solution you have produced a super saturated solution so some of the minerals fall out. The simplest way to demineralize water is with an ion exchange resin. These are marketed as Zero Water pitchers, buying distilled or purified (reverse osmosis ) water at a grocery store is cheaper.
I installed a reverse osmosis unit in my house, very pure removes over 90% of dissolved minerals. This water works great with a few drops of photo flo. Really is you use distilled water for your final rinse you need very little in the way of wetting agent.
Best Regards Mike

mshchem · Oct 22, 2016

pdeeh said:
I can't help wondering why you're choosing to ignore the manufacturer's instructions.

I had endless problems with drying marks using Ilfotol, following all the suggestions "on the internet" about using drips and drops and ignoring what Ilford themselves said.

Then with stunning originality I decided to follow the dilution instructions on the label, and Lo! I never had drying marks again, whether I use distilled, deionised or indeed my own nasty chalky tap water.

Suggestion: Try 2 drops, report back

I must say, good thinking reading the instructions. I have found, from time to time that re-reading is a good idea as well
Best Regards Mike

Stephen Weston · Oct 23, 2016

I currently use Photo Flo and squeegee and have not had any problems (Touching wood). I use a drinking straw to measure out a few drops and add it to the tank and then pour the tap water in. I then give it a couple of inversions and leave it to sit while clearing the rest of the stuff away. The squeegee would be soaking in warm water while I develop the film. Remove the reels and then transfer the squeegee into the Photo Flo while I shake off the reel /reels I then squeegee the film before hanging to dry. I have been lucky perhaps in that the two squeegees I have work a treat and have never damaged a film but I have had a couple of sets where no matter what I did they would skip across the film. Though they again didn't cause any damage they didn't do a very good job of removing water either so they ended up in the bin.

RalphLambrecht · Oct 23, 2016

obviouslygene said:
depends on wetting agents. some people squeegee their films, either with a squeegee or a tool.
i use fujifilm driwell, there are specific instructions to only sit it in for 30s and NEVER squeegee.

I squeegee my films between two fingers to get rid of excess water;then let it hang and dry;no water marks or damage to the film.

pdeeh · Oct 23, 2016

bvy said:
How did you arrive at that?

well obviously I read only half your post, and that carelessly, and then proceeded to comment only to ride a hobbyhorse of mine.

carry on.

jonasfj · Oct 24, 2016

mshchem said:
You are not demineralizing water by boiling it.

Yes, you are! Dissolved CO form carbonates with dissolved minerals when boiling and when cooling those are precipitated as solids. At least it says so in my chemistry book from high school.

mshchem · Oct 24, 2016

jonasfj said:
Yes, you are! Dissolved CO form carbonates with dissolved minerals when boiling and when cooling those are precipitated as solids. At least it says so in my chemistry book from high school.

I'm not going to question the authority of your high school chemistry book.. I'm sure there are some heavy duty chemists on this forum. You are correct that if you have Ca2+ ions dissolved in water and you react it with CO2 dissolved in water it will form CaCO3, i.e. limestone. But the water that has dissolved Ca and Mg ions have counter anions dissolved as well, usually bicarbonate ions . So if you would add gaseous CO2, by bubbling through hard water you could effect a salting out of Calcium carbonate, ie limestone. However you will also form carbonic acid that will help to redissolve the Calcium carbonate.
I have a 35 year old chemistry degree, I'm not even sure we had discovered litmus paper when I went through. But I'm pretty sure you aren't going to significantly deionize water by simply boiling it.
I use a reverse osmosis setup as the water where I live is very hard.
Best Mike

jonasfj · Oct 24, 2016

mshchem said:
But I'm pretty sure you aren't going to significantly deionize water by simply boiling it.

Well, I'm not a chemist at all, but it seems to work for me. Tap water = stains. Boiled and filtered = no stains.

My water is hard and contain a bit of iron, which has been reported to be the cause of Xtol sudden death. My Xtol has never died on me and this summer I used solution that had been stored for 8months.

I cannot remember where I picked up on this, but I think it comes from a book. Perhaps The Art of Photography by Bruce Barnbaum.

I think boiling and filtering does good!

Cheers,

Jonas

MattKing · Oct 24, 2016

MattKing said:
It is far more difficult to reliably and repeatably measure 2 ml of stock solution and then dilute it 1 + 199 (also giving 500 ml of working solution at a 1:200 dilution).

There is a typo in my post above. I meant to post: "It is far more difficult to reliably and repeatably measure 2.5 ml of stock solution and then dilute it 1 + 199 (also giving 500 ml of working solution at a 1:200 dilution).

Question About Wetting Agents

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