TEA- lab or tech grade for Mytol?

[Mike Lyons]

Hi to all, and thanks in advance for any advice. The difference in price for lab grade TEA and tech grade is quite substantial from the costings I've done-the lab grade is approx Aus$100 for 500ml, while the 80% tech grade is $10 for 1000ml. That's a no brainer as to costs, but what effect will using the 80% tech grade have on the volumes I'll need for mixing Mytol? Or the instant version? Anything else I need to know before I start buying and mixing?
Mike

 

[Mike Wilde]

tech for me

I just buy what the photo retailer sells me - it is a no water liquid that acts also as the alkaline activator to set the pH in developers. Most of the action I belive is in the pH end of things, and here the tech grade should equal better grades. Handle carefully - it is quite basic. Rinse off spills. I measure it in syringes, and rinse the syringe in th solution to get all if it into the batch I am putting together. it is quite viscous.

Keep it warm - likely not a problem at your end, but here it can be, since the stuff -freezes- at 20C or so. I keep my stock sitting on the heating duct in winter, since the darkroom is frequently cooler than that when the door is closed and the heater/ print/hair dryer hasn't been running to warm the place up.

JD Photochem (google them for the excel file of their price list. I am a satisfied customer. not otherwise associated with the company) sell and mail order ships all over the world. You indicate that there are also supplier local to you; the JD stuff should set a price point for what is tech grade good enough for photchemical purposes.

 

[Photo Engineer]

The major impurities in TEA are diethanol amine and a mix of other amines. They impart a more ammonia like odor as their concentration increases relative to TEA.

They are slight silver halide solvents and also will change pH slightly, so using a low quality TEA may change the pH of the developer. It might be a good idea to keep that in mind.

Basically though, I see no real problem other than pH.

PE

 

[Tom Hoskinson]

Mike, I use the Commercial grade of triethanolamine, it works fine. According to DOW Chemical: TEA Commercial Grade is a solution of Triethanolamine containing >= 85% Triethanolamine and <= 15% Diethanolamine.

Diethanolamine is pretty close to inert (mildly alkaline) and is highly soluble in both TEA and Water.

See: http://www.dow.com/amines/prod/ethano-dea.htm

 

[gainer]

The Dow website has charts that show the differences between the grades in pH and other factors. The principal concern when you are making and testing your own developers is consistency from one batch to the next. I buy it by the gallon from www.chemistrystore.com at about $16 US. A gallon develops a lot of film. In most of the developers I play with, a gallon is about like a gallon of HC110 concentrate in capacity. I have not noticed a difference from one gallon to the next.

 

[Jordan]

The conventional formula for MYTOL does not call for triethanolamine. Are you perhaps thinking of "Instant MYTOL"? If you do end up using it, please let me know how/if it works for you.