Tetenal Indicet stop bath colour????

Ok, a quick and probably simple question.
I have been developing my b&w films using Tetenal Indicet stop bath. The bottle is fresh and in date etc.
Once mixed, the working solution is a yellow colour. I have developed quite a few films now, using the same 1lt and the solution seem to be the same colour as when I started. What colour is the indicator supposed to go? Will it just change straight away or gradualy fade to it?

Cheers

It will turn purple when exhausted. It will fade to it, and you will notice the colour changing as it approaches exhaustion. I change it when the colour is definitely not-yellow, rather than taking it all the way.

As Steve says, Stop Bath goes a sort of muddy yellow as it exhausts before finally turning purple

As its cheap as chips, don't worry about it, if your not sure chuck it away and start with some fresh.

I am always amazed at how clear and golden freshly mixed Stop is.

I rarely bother storing used Stop, I now just make fresh up each time - but I do quite a few prints or films in one go, so this might not work for you.

Martin

By the time it turns purple it should have been discarded some time ago. A better indicator is bromcresol green, which turns from yellow to blue at pH 3.8->5.4. The standard bromocresol purple used in Kodak's indicator stop bath turns from yellow to purple at pH 5.2->6.8.

Thanks folks. This batch has stopped qute a few films and is a strong yellow so maybe its almost time to dump. Any suggestion of a better and cheap stop bath?

If it's still strong yellow, don't toss it, it's ok. If you want to see how it changes, put some of it in a clear/white container (like clear film cans) and pour some used film developer in it, drop by drop. Agitate a bit and notice how the color changes. At some point, it will have a somewhat greenish yellow tint. You can toss it then, or use it a little bit more. If your pour more developer it will start getting purplish and it should be tossed. Put some more developer and it becomes definitely purple; it's dead. While it changes color, it becomes darker under a safelight, compared to fresh. Finally, if you want to find a cheap stop bath, you need to take into account the suggested dilution. That practically tells you how much working solution it makes. Search a bit and it will become obvious what is cheap or not, although I don't think you can find stop baths that are expensive in the long run.

Gritycityflicks said:

Thanks folks. This batch has stopped qute a few films and is a strong yellow so maybe its almost time to dump. Any suggestion of a better and cheap stop bath?

Click to expand...

Stop bath is made up of common cheap chemicals, here in Canada I can get 500ml of Ilfostop indicator stop bath for $9 this is diluted 1:19 so it makes up 10L of stop bath. Cheap enough when you use it 1/4L at a time.