Stop Baths - Why we need to use them? And how to make them!

In this weeks video we look at stop baths and when we might need them. We also examine how I make mine from any strength distilled white vinegar to the 2% I like for my stop baths. I demonstrate using the cross cross method to calculate any dilution.
John
www.pictorialplanet.com

[@lesliehowells]

Woah!!!! I'm so in love with this method now! Thank you so much!!! (Are you married?! Hee! I kid... sort of.) The generosity of people on the internet never ceases to amaze me.

[@paolociccone]

Love having the making of a stop bath already in the house. Another great demonstration of chemistry in action. Thank you, John, for the great information delivered with such clarity.

[@PictorialPlanet]

Isn't it cool!

[@tomamyx3980]

Hi, John... well, I have not been in a darkroom in over 40 years. In my "previous life" I was a journeyman pressman, certified in three methods of printing: letterpress, direct lithography and offset, as well as certified in graphic arts photography. Needless to say, I used to be able to find my way around a darkroom, so to speak. Now I find I'm just IN the dark! Afraid I seem to have forgotten more than I knew! That's what I get for having stopped all photography related activities around 1987 (I think it was). But I recently have begun to take it up again, got out my old Durst M301 B&W enlarger... and find myself totally befuddled! I stumbled upon your KZbin channel, and this is the second video I've watched. I chose it because I remember using white vinegar as a stop bath, both at the newspaper I worked for and in my little home darkroom. Sorry to ramble on, but I'm just so excited to have found your channel, and am looking forward to more videos. Hey... as an afterthought... I also found an OLD unopened bottle of Edwal TST developer. Might be fun to see how it works after all these years!

[@PictorialPlanet]

What a lovely comment, thank you. That Edwal developer is classic! Thanks for joining us. Sounds like you'll pick it all back up in no time at all.

[@cowboyyoga]

Hi John ! This work in the darkroom is all new to me. And am excited to get started. I have been ordering stuff for the last three plus weeks. There's a lot to get together. I was going to buy your book, but FedEx said that it was better to wait to see what happened with Russians. It has become a bit crazy here in Ukraine this week. I am sure thankful of your videos. It is nice to dive into them in the evening and learn a bit more.

[@PictorialPlanet]

Blimey! You're in the thick of it my friend! My thoughts and prayers are with you all. Ukraine, or should I say Great Ukraine, is in all our thoughts, prayers, and actions. Keep safe!!

[@cecilsharps]

thanks for the vid. i'm trying to teach my nephew how to develop film he has the autism so it's a much bigger challenge than i anticipated. I'm hoping that focusing on the math and equations might be the way to teach him.

[@mikeking7470]

I usually buy my vinegar during canning season when it is very cheap. I also use a 1% acid stop bath for film--one shot. But use it as a 2% solution for prints.

[@ChrisVidouras]

Very useful, thanks for sharing!

[@PictorialPlanet]

You're welcome, Christos!

[@nickwinn7812]

Yes I've always used stop bath for both paper and film. I think if one wants to be consistent one needs to know when development stops. I used to buy it, but as you say it isn't cheap, and these days I have much less money, so I use vinegar just like you. In all the time I used indicating stop bath i never once exhausted it to make it go purple. Litmus paper is very cheap if one wants to check the acidity of one's stop from time to time.

[@PictorialPlanet]

Yes, litmus paper is the key to confidence. Thanks for your comment, Nick!

[@Sebastian-lw1ei]

Thank you so much! You made it so easy 😂

[@randallstewart175]

The point of using a stop bath is to stop development to maintain a precise control over the extent of development.. Using a water bath instead doesn't stop development, but just starts slowing the process. There was a practice once used often where film was developed by alternating short periods in a developer with short periods in a water bath. The purpose and effect was something like what people try to get with stand development today, except that the old practice gives much more control and reliability.

[@PictorialPlanet]

Hi Randall! Yes, except I don't agree about stand development vs. developer/water baths, at least with tank development. Stand development has as much control and is perfectly repeatable and very reliable. How have you found stand development to be unreliable in any way?

[@PictorialPlanet]

Oh, and I'd just add that water stop baths have been used for many years, especially with pyro developers since at least the time the book of pyro was published by Gordon Hutchins, the formulator of PMK. This was because he recommended keeping the process alkaline to maintain maximum stain. Since then many photographers including the formulator of Pyrocat and 510-pyro have recommended it. I have used water stop baths since around 2002 for pyro developers with absolute success. The development time takes into consideration this method of stopping the film.

[@marike1100]

@@PictorialPlanetWas going to say the same. Lately I’ve been using Pyrocat HD almost exclusively and a water stop bath works perfectly.

[@CFM.]

How come I had never watched this video??? Anyways, perfect timing. My ilfostop is almost done and I was about to buy more. I assume this is a one time use dilution. Is this correct? Thanks for keeping the channel full of great content going!

[@PictorialPlanet]

Thanks for your comment. As the channel approaches 100 videos it's easy to miss one :) This stop can be used for ten films (probably more but I'd stop there to keep safe).

[@LYSYSTUDIOS]

For film, I have always used water and had no problems, developing around 10 mins (for the last forty years). Having said that, stop bath for film might be specifically useful if one is playing with underdeveloping. The development process has a certain curve and it simply slows down towards the end of the standard development time so much that the difference is minimal. However, if you want to underdevelop (intentionally overexposed film, for the purposes of more varied tonality), you really have to stop instantly. For papers it is a different story, especially for fiber, the reaction of developer and fixer can screw it up very quickly, in a matter of months and not only in the corners. But vinegar stinks really badly... Citric acid?

[@dirkvandamme]

Hi, I am going to switch to vinegar as stop bath. therefore I have just am more question on the dilution. Why do you choose in particular 2% as distilled strength and not for example 1% or 5% or more. Many thanks upfront!!! Your videos are very much appreciated!!

[@PictorialPlanet]

This is an interesting question! The developer is quite alkaline - depending on the particular accelerator used from sodium sulphite to hydroxide. A stronger vinegar solution would stop the development more quickly but might chemically shock the emulsion and could cause reticulation of the gelatine. A weaker solution might not have the ability to stop development evenly and effectively. 2% has historically been found to be a good safe strength.

[@baggerrider8073]

Do you reuse the 2% vinegar stop and if so how many times since there isn’t a color change to indicate exhaustion? As always, thank you so much for your informative and useful information via the videos. They have been so very helpful to me.

[@PictorialPlanet]

Yes, I reuse it. As long as it's PH6 or lower I keep using my vinegar stop baths. Test using colour litmus paper.

[@andrewfindlayphoto]

This explains why one of my pictures went brown 10 years later 😮

[@dirkvandamme]

many thanks for the video - very much appreciated. i use ilford and adox stopbaths for resp. paper and film. what you are presenting seems a very good economical alternative. Is it also eco-friendly or is the developer getting disolved into the stopbath? how can you check if the stopbath is still properly working or you just dispose it after you have used a certain number of times?

[@PictorialPlanet]

Good questions, Dirk! The vinegar stop itself is safe for the environment but the stop will carry some developer after use. If one uses something like Crawley's FX-55 then the used stop will be no worse than many household cleaners. As for capacity, the 2% solution can be tested, every three or four films with litmus paper - as long as it's acid it'll work. For paper I'd advise to use a separate litre of 2% and test with litmus paper before each session.

[@baggerrider8073]

I was out of stop bath and used your vinegar recipe. It worked very well. Thank you for the video. I just have a question. If I am using an acidic fixer like Ilford rapid fixer, is there a reason why the fixer is could not be used as a stop bath as well? I’m sure there’s an obvious answer but it’s been 40 years since I’ve developed film and I’ve only recently gotten back into film after using digital since the early 2000’s. Thank you for your most informative videos.

[@PictorialPlanet]

Stop baths were not always as common as they are now. They were recommended when a developer formed scum on the film. I think high sulphite developers were prone to this scum. The stop bath dissolved the scum as well as impurities on the film from hard water. However, stop baths also lengthen the life of your fix which may or may not be a concern to you. There also might be a reaction between the developer and the fix causing odd stains. This can be seen easily on darkroom paper where a stop bath has not been used but not so easily on film. But the risk is real so it's best to either use a stop bath or a good rinsing with water (at the same temperature as your developer). The advantage of a stop bath over a water rinse is that the development is stopped almost instantly so development timing can be done very accurately - a must for zone system work.

[@saidanehabib]

Nice useful video, do you use the same strength for color film developing? Thank you.

[@PictorialPlanet]

2% is a good strength but no higher.

[@jagman1953]

I use stop bath for paper and film both. As soon as I use up what I have purchased I will be switching to vinegar. Does vinegar stop also work on color film development and RA 4 paper processing ? Thanks for another great bit of information.

[@PictorialPlanet]

Thanks for your question Paul and you're very welcome! Yes, all stop baths (colour and BW) are the same and all are diluted about 2% to work. Colour development, just like BW development, is the development of silver halides in the emulsion, the difference being that the silver is then bleached out in the colour process before the fixing (the blix). Acetic acid (distilled white vinegar) is usually recommended as the stop.

[@isaiaszepeda42]

For how long do you process film and paper also with citric acid for how long do you stop paper and film

[@PictorialPlanet]

With film and paper I stop for 20-30 seconds

[@raybeaumont7670]

Cheers John. I never use a stop for film - just 3 changes of water after dev times of 10 and 15 mins. The dev (one shot) is pretty knackered by then. For paper, I have always kept the used fixer from the previous session - so old fixer then fresh fixer. The same for both FB and RC papers. Works for me.

[@PictorialPlanet]

That's great, Ray! You have a solid plan :)

[@Max-nv4fb]

I recently started using Kodak SB8, 1L water and 15gr citric acid. Really nice no odor at all which is quite important since I have almost no ventilation in my darkroom... You have any experience or tips and tricks using this stop bath?

[@PictorialPlanet]

The safest of stop baths, nice! I've published 10g/litre citric acid stops so you're right in the ball park. But you could reduce your 15g to 10g without problems.

[@Max-nv4fb]

@@PictorialPlanet Thanks! yeah I love that stop bath, its really cheap and no odor!

[@rolft.7697]

I was thinking about to make my own stop bath with a low percentage citric acid solution . Would you recommend to do that ?

[@PictorialPlanet]

Yes! Excellent stop bath. Use 10g per litre.

[@dominiqueguillemard9232]

Hi John. Thank you for your interesting video. I don't use a stop bath for developing FB paper because I use an alkaline fixer. I think an acid stop bath is incompatible with this type of fixative. Should I fear brown spots on my prints in the next few years?

[@PictorialPlanet]

Hi Dominique! First, an acid stop is compatible with an alkaline fix so don't worry about that. Secondly, if you are wanting your fibre based prints to wash more quickly then use a stop bath after the developer for 30 seconds then a water bath for 30 seconds, then fix in your alkaline fix. This technique should help stop the dreaded brown spots in years to come.

[@Ivan-gh1wm]

Hi John, great works! I am wondering if I shoud reduce the dilution for the stop bath in C41 process considering developers differ in their acidity?

[@PictorialPlanet]

Hi Eason! I'm not a colour guy.

[@dalehammond1749]

In the final analysis, Stop Bath is vinegar. Weak vinegar. Just like the water spot prevention formula is basically, soap.

[@PictorialPlanet]

Absolutely! Many years ago I used Fairy Liquid, one drop at a time, for spot prevention. Worked a treat.

[@Sebastian-lw1ei]

John, what about making a stop bath for an Ascorbic Acid developer like Xtol? Does 2% vinegar still works in this case or should we just rinse with water (dev time 10+ minutes)? Thank you for your help!

[@PictorialPlanet]

A 2% stop bath is perfect for xtol. Although it's an ascorbic acid developer is actually still alkaline, just like all the rest. The stop bath has no adverse effects on the xtol developer so go for it :)

[@nnnandaaa]

is there any temperature requirements when diluting vinegar part and water part or it just diluted at any random temperature?

[@PictorialPlanet]

Any random temperature to mix. However, when using the Stop it should of course be at a similar temperature to the developer.

[@EduardoRomero1965]

I hate stop bath, I use water. I develop film only since I don't have space for a dark room. I'm going to try this vinegar solution since with vinegar I'll think of food. =) Thanks!

[@PictorialPlanet]

I think of food too, fish and chips! Gotta love the vinegar :)

[@andyandyfrogy1113]

Can you use this method for color film as well? I have all the chems for Kodak ECN2 development, but I need a stop bath. Thanks.

[@PictorialPlanet]

I've hung on a while to see if anyone else had the answer to this but not yet it seems. My gut says yes, a stop is a stop. If you can use a regular Ilford or any manufacturer's stop then you can use this one.

[@andyandyfrogy1113]

@@PictorialPlanet thank you!

[@MARKLINMAN1]

So when buying and using stop bath, do you use it full strength? and then save and re-use? or is it 1 time use? Thanks in advance, i bought the KODAK one you show in this video and want to know how to use it EXACTLY.

[@PictorialPlanet]

Hi Sax! So, I dilute the stop as stated on the bottle to make 1 litre of working stop at a time. I then use it over and over until the colour starts to change. I then toss that litre and dilute from the stock to make another litre. You'll find it lasts many films or paper sessions. BTW, I don't use stop made for paper developing for film or film stop for paper. I keep them separate so there's no cross contamination. It's just belt and braces.

[@MARKLINMAN1]

@@PictorialPlanet Ok, thank you.

[@standarduser7105]

None of my area has 2%, they only have 30% distilled vinegar. I’m not good at dilution calculations, but my results for a 1000ml bottle are 933ml of Water and 67ml of Distilled Vinegar. I’m hoping I did that correctly.

[@PictorialPlanet]

Sounds good 👍 your calculation is right and will give you a great stop bath.

[@joiscara7191]

I’m willing to bet you’re getting that 30% Distilled Vinegar from Home Depot, I’ll try it out.

[@joaovtaveira]

What about time, for how long do you keep film in contact with stop bath? And how do you mix them?

[@joaovtaveira]

@@PictorialPlanet thanks, question answered.