minimum of metol

[luxikon]

I want to make my own Perceptol by scratch. To make 300 ml of a 1+3 working solution from it leaves 0.5 g of metol in the developer. Will this small amount of metol be enough to develop a 135 or 120 film? If not as I suppose how much is needed instead?
Best
Klaus

 

[Anscojohn]

I want to make my own Perceptol by scratch. To make 300 ml of a 1+3 working solution from it leaves 0.5 g of metol in the developer. Will this small amount of metol be enough to develop a 135 or 120 film? If not as I suppose how much is needed instead?
Best
Klaus

*******
Many old and famous film developer formulas do well with that amount of metol per liter. Although I am not a photo chemist, I would expect that the type and amount of accelertor is important with those levels of metol.

 

[el wacho]

do a search on dancqu's posts. i remember he has experimented on this topic and posted results.

 

[dancqu]

One Half Gram, Plenty

I want to make my own Perceptol by scratch. To make 300
ml of a 1+3 working solution from it leaves 0.5 g of metol
in the developer. Will this small amount of metol be
enough to develop a 135 or 120 film? If not as
I suppose how much is needed instead?

One half gram of Metol is plenty. I've found 0.3 gram also
plenty. I regularly use the 0.5 amount with a very dilute
D-23; a roll of 120, 500ml volume. Just what is the
formula of that Perceptol you are to brew? Dan

 

[luxikon]

It's a formula discussed in another thread of this forum:
Metol......................................5 grams
Sodium Sulphite, anhydrous........100 grams
Sodium Chloride (iodine-free)......30 grams
Water to make.........................1 litre of stock solution.
I can spare the sequestering agent.
I want to dilute 100 ml of stock 1+3 for better tonality.
Ilford suggests 20 min developing time for 1+1 dilution (for EI 200 and 20°C).
How much should it be for a dilution of 1+3? The film is Ilford SFX 200.
Klaus

 

[Murray Kelly]

One half gram of Metol is plenty. I've found 0.3 gram also
plenty. I regularly use the 0.5 amount with a very dilute
D-23; a roll of 120, 500ml volume. Just what is the
formula of that Perceptol you are to brew? Dan

I once wondered about a developer along these lines for Imagelink-HQ and you asked if I needed a formula to start out with.
I flippantly replied - metol and buffered borax (very low pH) - but you never responded. What would your suggestion have been? I really would like to hear.
Murray

 

[dancqu]

Imagelink-HQ?

I once wondered about a developer along these lines
for Imagelink-HQ and you asked if I needed a formula
to start out with.
I flippantly replied - metol and buffered borax (very low pH)
- but you never responded. What would your suggestion
have been? I really would like to hear. Murray

Seldom I don't respond. A developer for Imagelink-HQ.
I'm in the dark with that one. Dan

 

[john_s]

To make 300mL of 1+3, you need 75mL developer plus 225mL water.

75mL developer using your formula gives .375g of metol. Dan says it's enough.

Consider these two possibilities:

1. A large amount of very dilute developer that does not get used up much during the development but which still produces edge effects and compensation due to exhausted developer in the emulsion, and

2. Just enough of the same diluted developer to cover the film and which might become exhausted to a significant degree during development, and which would probably need a bit more time due to the general exhaustion, in order to reach a similar over all density.

How would the shadow speed compare in these two cases?

My guess is that 1 would be better than 2.

Developing to near exhaustion is recommended from time to time, but I'm not convinced that it is optimal if shadow speed is important (and isn't that all the time?)

 

[dancqu]

OP's Post #5, "100ml" not 75mL. Dan

 

[john_s]

OP's Post #5, "100ml" not 75mL. Dan

After reading the first post, I thought 1+3 to make 300mL would be 75mL developer plus 225mL water to make 300mL total.

I agree that he would be better off making 400mL of diluted developer.

Dan, what do you think of my question about exhaustion?

 

[Ian Grant]

Whether it's Preceptol or ID-11/D-76 there is a high degree of compensation taking place because of developer exhaustion, this is a reason why with some High Acutance developers the recommendation used to be 600ml of developer per film. Using 400ml of dev will help a little. I preferred to use a 1+2 dilution.

Ian

 

[luxikon]

Thanks John for the hint. I should have written 400ml in my first post.

 

[dancqu]

No Recommendation

It's a formula discussed in another thread of this forum:
Metol......................................5 grams
Sodium Sulphite, anhydrous........100 grams
Sodium Chloride (iodine-free)......30 grams
Water to make.........................1 litre of stock solution.
I can spare the sequestering agent.
I want to dilute 100 ml of stock 1+3 for better tonality.
Ilford suggests 20 min developing time for 1+1 dilution
(for EI 200 and 20°C). How much should it be for
a dilution of 1+3? The film is Ilford SFX 200.

Save for the chloride that formula is a 2/3 strength
D-23. I've had good results using my formula D-23;
8 - 80 grams, metol - sodium sulfite. Dilution 1:7,
500ml, 16 minutes with a few inversions each
2 or 3 minutes, Acros 120.

Perhaps chloride slows development. Apart from
that I'd think your formula would show times
similar to mine. I've not loaded a developer
with chloride and tested for times so will
not recommend a time. Dan

 

[Anon Ymous]

...Perhaps chloride slows development...

NaCl acts as a restrainer and a silver solvent.

 

[Ian Grant]

The nChloride slows development so times need to be almost doubled and there's a similar reduction in film speed. Ilford P10 technical datasheet in the 60's suggested chloride could be added to ID-11(D76) and ID-2 for much finer grain.

Ian

 

[Anon Ymous]

The nChloride slows development so times need to be almost doubled and there's a similar reduction in film speed. Ilford P10 technical datasheet in the 60's suggested chloride could be added to ID-11(D76) and ID-2 for much finer grain.

Ian

Interesting Ian, do you remember the amount of NaCl for 1l of D76 stock?

 

[Ian Grant]

Here's the relevant section, they suggested Ammonium Chloride but I guess Sodium Chloride would work, needs to be Iodide free.

Developers containing silver halide solvents
Certain fine grain formulae contain silver halide solvents such as hypo and thiocyanate. These depend for their action on the fact that some of the silver dissolved during development is redeposited in a very fine form to reinforce the final image. Ilford ID-48 Developer is of this class. Such developers give considerable reduction in grain size but require 50 to 100 per cent extra exposure. Both Ilford ID-11 and ID-2 developers may be simply modified to work in this way.

ID-11: Add ammonium chloride to ID-11 in the proportion of 20 g. per 500 cc working solution.

Camera exposures should be increased by about 50 per cent and the development times are double
those specified for ID-11.

ID-2: To ID-2 diluted 1 + 2 add ammonium chloride in the proportion of 5 g. per 500 cc. developer.

I'd go for 30gm/litre Sodium Chloride as in Perceptol/Microdol-X

Ian

 

[Anon Ymous]

Thanks!

 

[dancqu]

Exhaustion?

Dan, what do you think of my question about exhaustion?

I'm not sure just what Is the question. Local depletion is
a characteristic of any developer and the more dilute the
developer the more is characteristic local depletion. All
things being equal.

Development compensation is the result and the more
so if metol is the reducing agent. Metol is inhibited in
it's development by the local build up bromide. Dan