what is 1+1+100 dilution ?

[raytoei@gmail.com]

hi,

i was reading up on Pyrocat HD and the dilution is 1+1+100 for A and B.

assuming a AP tank of 300ml, does that mean I should add something like 3ml of A, 3ml of B and 296ml of water ?

what about 1+1+200 dilution ?

1.5ml of A, 1.5ml of B and 297ml of water ?

raytoei
just checking, brain a little slow today.

 

[Corran]

3+3+300

1.5+1.5+300 for the 1+1+200

Not that the extra 3-4ml would matter, but you don't have to "subtract" the A+B solution from the total.

Have fun. I gave up on Pyrocat partly because of the hassle of those measurements.

 

[Tom A]

You are right. 1:1:100 means 1part A, 1 part B and theoretically, 294 parts of water. I would not fret too much about the 294 ml and measure 300 ml and add the 3ml of A and 3 ml of B (300 versus 306 ml does not make a difference).
With the 1: 200 - 1.5 ml A/1.5 ml of B and 300 ml of water. If you use a small tank - like 300 ml - the problem is the initial 1 min of cont. agitation - try to be consistent with it. You can roll the tank back and forth in the sink.

 

[Corran]

I am pretty sure that 1+1+100 = 102, not 100.

Therefore, if you did 3ml A, 3ml B, and 294ml water, your dilution would actually be 1+1+98.

I just looked up some chemistry instructional videos and I am pretty sure this is correct. If you mix T-Max Developer at a stock solution of 1:4, you don't mix 100ml of developer to 300ml of water, you mix it with 400ml of water, for a total of 500ml of working solution. Should be the same for Pyrocat.

Unless I've been mixing developer wrong for 6 years and all those chemist instructions are different than how we do film dilutions.

 

[Fotohuis]

In chemistry it is different.

In photo chemistry 1+1+100 is always meant 1 part A, 1 part B and 100 parts water. In the Kodak instructions 1:4 means 1+4.

Pyrocat-HD is one of the finest Pyro developers. To keep it simple in a 300ml tank: 3ml+3ml+300ml water.
Especially in high dilutions you have to take care of the minimum amount of concentrate for each 135-36, 120 roll film or sheet film area.

 

[Corran]

That's exactly what I just said. So apparently it is the same.

 

[Godfrey]

I'm probably not following convention. When I want to make 200ml of developer at a 1:49 dilution, I add 4ml developer to 196ml of water. I'm guessing that some would write this 4:200 and others 4:196.

Whether the 4ml water difference is significant .. I doubt it!

G

 

[jschrader]

1+100 and 1:100 is failry the same, as all agreed.

It makes a difference if you dilute D76 1+3 or 1:3, because 1+3 clearly sais take 1 part and 3 parts, but with 1:3, it is not clear if it means 1 part mixed with 3 or diluted to 3 parts, which would be 1+2.

I think this is why the 1+X type formula is better

 

[Corran]

You're right, 4ml of water doesn't matter.

But if someone did indeed mix a 4:200 (1:50) dilution by putting 4ml of developer into 196ml of water for a total of 200ml of solution, then I would assume for a different developer that is supposed to be 1:4, they would mix 50ml of developer with 150ml of water to get 200ml of solution, which is to me not 1:4, but 1:3 (1+3)

How I understand it is that [:] is equivalent to [+]. If [:] means "in" instead of "plus," then I've mixed things wrong forever. 1 part (IN) 4 total parts is way different than 1 part (PLUS) 4 parts.

Now I'm reading other papers/tutorials and it is giving me different answers. I am confused now.

 

[raytoei@gmail.com]

thanks much for the info. two eastern europeans are selling pyrocat hd, so i am trying it out.

 

[Fotohuis]

1:50 or 1+50 means for a 500ml volume:
500/(1+50) = 9,8ml developer in a total volume of 500ml.

That a lot of people are doing 1+49 , 500/(1+49) = 10ml developer in a total volume of 500ml is wrong but not relevant in such a high dilution.

So nothing to be confused: 1+ x is simple to remember. Nothing wrong to put 10ml developer in 500ml water with a total volume of 510ml.

two eastern europeans are selling pyrocat hd, so i am trying it out.

Well, Pyrocat-HD and Pyrocat-HDC is standard available in our web shop and indeed, I have it mixed in a labority in Ukraine.

 

[raytoei@gmail.com]

thanks all for the comments.
i did a 1:1:200 or 1+1+200 stand developed
with Pyrocat HD this evening
basically 1.5ml of A, 1.5ml of B per roll
this is way overdeveloped at 50mins @ 30c.
Inverted, the brown negative is Blue.
Also I quite like the tonality of the negative.
Compared to my current XTOL.

here is a picture of a friend i bumped into this afternoon.
Captured on the Leicaflex SL with 50f2 and Kentmere film