life of dichromate bleach

[nikonr10]

Hello ,
Can any one help me, with when you know that the life of a Dichromate bleach is over ,
still yellow , but not that bright orange it was when made , have used around 10 times ,

To the DIY chefs please/ some input , Thank you ,

[Angus]

I would take the colour not having changed as a positive sign.

Last time I made my own I used it around three years after I made up the solution and it was OK for reversal film bleaching. It had been stored in a chemical resistant plastic bottle on a shelf in my bedroom

[71er]

I guess you can't judge by the colour. Mine lost its bright orange colour already after bleaching two films. You will see when it's exhausted on the developed film as very bright areas on the image have some greyness in them.
Due to the poisonous character of dichromate I changed to permanganate a few months ago and after some trials (there is a few problems to be solved) I am getting the same results now - with permanganate it's one shot by the way. If you are interested and you need some help I'm going to answer your questions.

[aj]

Due to the poisonous character of dichromate

The bath is not poisonous. It is strong acid. So its danger is immediate eye or skin damage.
The basic chromate powder should not be snorted for extended periods of time. Lab rats don't react well to that after passing so much percent of their bodyweight.

[71er]

The bath is not poisonous. It is strong acid. So its danger is immediate eye or skin damage.
The basic chromate powder should not be snorted for extended periods of time. Lab rats don't react well to that after passing so much percent of their bodyweight.

A small excerpt from the Material Safety Data Sheet by Sigma Aldrich for Potassium Dichromate Solution (http://www.sigmaaldrich.com/MSDS/MSDS/D ... partialmax):
2.
HAZARDS IDENTIFICATION
2.1
Classification of the substance or mixture
Classification according to Regulation (EC) No 1272/2008 [EU-GHS/CLP]
Acute toxicity, Oral(Category 4)
Acute toxicity, Inhalation(Category 4)
Skin corrosion (Category 1B)
Respiratory sensitization (Category 1)
Skin sensitization (Category 1)
Germ cell mutagenicity (Category 1B)
Carcinogenicity (Category 1B)
Reproductive toxicity (Category 1B)
Specific target organ toxicity - single exposure (Category 3)
Specific target organ toxicity - repeated exposure (Category 2)
Acute aquatic toxicity (Category 1)
Chronic aquatic toxicity (Category 1)
Classification according to EU Directives 67/548/EEC or 1999/45/EC
Toxic by inhalation.
May cause cancer.
May cause heritable genetic damage.
May impair fertility.
May cause harm to the unborn child.
Harmful if swallowed.
Harmful: danger of serious damage to health by prolonged exposure through inhalation.
May cause sensitization by inhalation and skin contact.
Irritating to eyes, respiratory system and skin.
Very toxic to aquatic organisms, may cause longterm adverse effects in the aquatic environment.

OK, I might have used the wrong word: it's maybe not an immediate poison but it is toxic.

[nikonr10]

[quote="Angus"]I would take the colour not having changed as a positive sign.

Last time I made my own I used it around three years after I made up the solution and it was OK for reversal film bleaching. It had been stored in a chemical resistant plastic bottle on a shelf in my bedroom [/quote

Well Thank you , For all your wise words ,
I take it it is still ok ? , will not put next to the aftershave then !

[nikonr10]

Did some more home cooking this night/ still Good / thank s for the input !