any merit in pH monitoring if equipped already?
This is probably a question analogous to the use of a densitometer...learn something from it, but once you know what you're doing, it's unnecessary.
I obtained a lab pH meter being eliminated at work. It is missing a sensor, so I would like to balance the cost of a sensor against whether there is any merit in using it to check solution life, etc.
As far as the value, I'd be unloading other acquisitions to pay for it so it would be $ sleight of hand anyway.
Thanks for comments.
Being a colour worker who mixes up his own chemicals I find I require a pH meter and many years ago I found the Phep pocket meters to be terrific, because they worked and are cheap.
The second model I purchased is waterproof and is computer driven. That is, the temperature of the solution is accounted for when making measurements, you don't have to get the soloutions to 25º C for accurate measurements. It takes literally a few seconds to measure pH of almost any solution once it's calibrated, which is also very easy.
I would seriously look at the Phep range of meters, they are available ready to go for about $130 Australian, which is something like $100 US.
To answer your question about whether or not it is worth having a pH meter for B&W (I assume). With regular mixing of different solutions you'll be able to monitor things you don't know you should monitor but you do, with funny effects later on.
An example, is the first time I used Xtol developer when it was released. I purchased some 1 litre kits and thought I would give it a go. I monitor all of my developing and I noted the pH of the solution after mixing, in my notes. This was some years ago as you would know. Eventually I used up my 1 litre kits and went to buy some more, only to find out that the small kits had been replaced with the huge kits that I didn't need or want. I decided to give Xtol a miss.
Recently after finding this site I managed to find what appears to be the Xtol recipe, I'm currently one item short of the necessary chemicals, but when I acquire it I'll be mixing up my home Xtol and then I'll monitor the pH from the original to what I've mixed up. In this instance you'll find pH meter quite handy.
I'm by no means chemistry minded, I just read lots of articles and stumble along reasonably well. I do find intermittant use for a pH meter in a B&W darkroom for accuracy. However in a colour darkroom, it's pretty much an absolute requirement.
This one has a glass sensor that talks both temp. and pH so the whole thing reads correctly. Then there's a control to compensate for the temperature it reads.
I suspect pH isn't the only thing that changes as the mix changes with usage, but that's a common process control parameter.
Parts of New England have some of the most sparkling clear, mountain spring-fed tap water in the country.
But an urban legend about tap water has existed among photographers here for decades.
The theory is that autumn leaves fall into the reservoir and decompose, changing the ph. In winter, the heavily-salted roads which border the reservoir drain into it with the snow melt. In addition, the city water department is daily fiddling with the amount of chlorine and other chemical additives.
All of the above must change the tap water’s ph enough to affect the developer action. Therefore, distilled water is necessary to achieve consistency year ‘round.
A ph meter would test the validity of this legend. If it is false, we could all save a ton of money on bottled water. Not to mention hauling those five-gallon jugs down the cellar stairs!
Put one drop of silver nitrate solution into a small amount of water and watch the precipitate form. This is silver halide formed from the chlorine and other salts in your water. Under normal conditions, this will cause no problem in photographic solutions, but if you are making any light sensitive material it is very bad.
The pH changes in water are not remarkable and are generally harmless as the water has no buffer capacity. Remember that pH is different than buffer capacity.
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I have never had inconsistancy or chemistry failure using LA City water. - It is a mix of aqueduct water and well water. The ph is usually 6.5 or so. I might feel different if it smelled like sulpher or had a heavy mineral content.
My photos are always without all that distracting color ...
Although many of the scientific types out there will undoubtedly quibble, I have found pH papers adequate for any of the photo processes I've ever been involved with. Yes, I know they're not as accurate as meters, etc., but the point is, they work well enough.
Originally Posted by Murray@uptowngallery
I've lived on three continents, been subjected to varieties of city water supplies (Paris was the worst--loads of calcium carbonate precipitates for which I needed to use water softener in my final rinse so that they wouldn't stick to the film in little particles, although it didn't affect development.), and so far the papers have worked just fine.
I've encountered lots of problems in development over the years, but nailing down the pH with utmost precision wasn't one of them. The papers are certainly accurate enough to distinguish between, e.g., pH 9 and pH10, and that's good enough. For my Ilfochrome homebrew contrast controlling developer, I had to have at least pH 10 for it to work well.
Thank you, all.
I hope someday to do argyrotype, probably Mike Ware formula. First he got me all worried about pH of water in processing, then he comes up with a solution :O).
I'll have to see what a probe costs & whether the probeless meter would bring anything on eBay :O)
Last employer dumped a Crown Graphic (needed repair by the time I got it), a 12"x18" UV plate burner (BLB lamps) and a 3M/X-Rite densitometer. I scavenge, ponder the merit of someone else's junk being my treasure, then if all works out I use it or it breathes life into another money-pit project.
Larry, you forgot to mention www.microessentiallab.com
Originally Posted by Maine-iac
They've a huge selection of ph measuring and buffer
media. A silver test paper and other test materials
are available. Only $5 S&H. Dan