Quick Question (ish) re: Microphen re-use

[ashreid20]

Hi,
I am new to the forum and relatively inexperienced in the darkroom.
I have a quick question about Microphen re-use.

Ok, so out of my liter of stock solution i have used
600ml -> 2x Tri-X @ 3200 (stock - 25min)
200ml -> 2x Pan F+ @ 50 ( 1:3 - 11min) - discarded after use
I then did a further Tri-X @ 3200 using my remaining 200ml of fresh stock topped up with 100ml of stock from the first 2x Tri-X increased the dev time to 27-28min

So, I now have 800ml of stock, 700ml of which has been used to develop 3x films. 100ml has been used i don't know how much.

If you can follow that at all my question is, if i were to use 600ml of the stock to do a further 2x Tri-X @ 3200. what would my dev time be at 20C?

I know the best course of action would be to throw it, I am just curious as to how you would work it out.

 

[tlitody]

ilford say you can develop 10 rolls of film in a litre of stock microphen. For each subsequent film being developed then add an extra 10% to developing time of the first film. So for 4th film it would original dev time plus 30%.

 

[ChrisN]

And I believe that is based on returning the used developer to the original container each time.

 

[tlitody]

And I believe that is based on returning the used developer to the original container each time.

Yes.........

 

[ashreid20]

so my next to rolls would simple be my 4th and 5th rolls.. and i could give it maybe a minute or two more because of the 100ml that has been used a bit more?

 

[tlitody]

so my next to rolls would simple be my 4th and 5th rolls.. and i could give it maybe a minute or two more because of the 100ml that has been used a bit more?

If you developed two in your first batch, then I would add 20% for your second batch of two films and then another 20% for your third batch of two films.

5% to 10% difference is really a very small change in development effect so it won't make a major difference if its 5 or 10% out from what it should be. 20% out and it becomes noticeable.

I would mix all your remaining dev together and it will develop 8 rolls in total. You have already developed 5 so you can do another 3 rolls, Just add 50% to original time for next batch. This is a bit of guess work on my part but it won't be far out.

p.s. manufacturers are a bit conservative about the capacity of developer. I suspect you could probably develop 12, 14 or possibly more rolls of film from a litre of stock.

 

[Beemermark]

I'd recommend you use ID-11 or D-76 as a developer. Mix up a gallon and then use straight or 1:1. One problem with Micro-phen is trying to mix very small one shot quantities.

Fix your negatives for about 3 or 4 minutes and inspect. If the film is clear continue to fix for another 3 or 4 mintues. I always reuse my fixer until the developing times get get too long. Stick it in the sink and wash for 5 minutes. Scan and throw the negative away.

 

[tlitody]

I read your post wrong so you have only done 3 films in your 800ml of dev and not 5. So add 30% to dev time for next batch and not 50% as I said.

 

[ashreid20]

Scan and throw the negative away.

not a chance!

would ID-11 or D-76 be good for push processing? i will look into it anyway.

I read your post wrong so you have only done 3 films in your 800ml of dev and not 5. So add 30% to dev time for next batch and not 50% as I said.

well 3 (+1/3 ?). thats great though, thanks for your help.