Rodinal Dilution for efke R100

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Greg Winterflood
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Joined: Tue Mar 27, 2007 2:11 pm

Rodinal Dilution for efke R100

Post by Greg Winterflood »

I have just received 25 rolls of efke R100 in the mail. Thanks Jon.

And, I have been given a 500mL bottle of original Agfa Rodinal. I can find no Use By Date on the carton or bottle. As I live just over 1,000 miles, in any direction, from a city large enough to have a store which might carry more Rodinal, I'm wanting to stretch my single bottle.

I'm wondering what dilution I should use first up? :?

Jim Appleyard
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Joined: Sun Mar 25, 2007 4:33 pm

Post by Jim Appleyard »

The great thing about Rodinal is that the concentrate in the bottle lasts for decades and you can use any dilution you like; 1+25, 1+50 or 1+100. Some folks use 1+75.

I like the 1+100 dilution for 16 min with Efke 25 at an EI of 20.

Don't worry about using the stuff up.

Greg Winterflood
Posts: 49
Joined: Tue Mar 27, 2007 2:11 pm

Post by Greg Winterflood »

Jim, thanks for the reply.

I take it that 1+100 equates to 3mL plus enough water to make up a total quantity of 300mL, and not 303mL? :?

I've seen other notations used, such as 1+9, which I read as 30mL + 270mL for a total of 300mL.

I might sound pernickity, but my father was a chemist and I grew up with graduated cylinders all around me! To me there is a difference between 1+100 and 1+99.

Dad used to use a Latin abbreviation q.s., quantum sufficient, which meant that after the Larks Tongues and Chicken Gizzards had been ground up, a "sufficient quantity" of water needed to be added to make up a quantum totalling 100.

So I am wondering if your 1+100 is the same thing as 1 qs 100 or 1+99?

Or is it really 1+100?
Last edited by Greg Winterflood on Wed Apr 18, 2007 11:23 pm, edited 1 time in total.

Ornello
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Post by Ornello »

Greg Winterflood wrote:Jim, thanks for the reply.

I take it that 1+100 equates to 3mL plus enough water to make up a total quantity of 300mL, and not 303mL? :?

I've seen other notations used, such as 1+19, which I read as 30mL + 270mL for a total of 300mL.

I might sound pernickity, but my father was a chemist and I grew up with graduated cylinders all around me! To me there is a difference between 1+100 and 1+99.

Dad used to use a Latin abbreviation q.s., quantum sufficient, which meant that after the Larks Tongues and Chicken Gizzards had been ground up, a "sufficient quantity" of water needed to be added to make up a quantum totalling 100.

So I am wondering if your 1+100 is the same thing as 1 qs 100 or 1+99?

Or is it really 1+100?
1:100 = 1+100. If you want 100 parts, make it 1+99.

Greg Winterflood
Posts: 49
Joined: Tue Mar 27, 2007 2:11 pm

Digits Count

Post by Greg Winterflood »

Ornello wrote:1:100 = 1+100
It didn't when I went to school in Pennsylvania.

Back then,

1:100 = 1 per 100 = 1 in 100 = 1+99 = 100, and

1+100 = 101

QED
Ornello wrote: If you want 100 parts, make it 1+99.
Are you saying that 1+100 = 1+99?

I imagine there might be a different linguistic convention among some photographers. That is what I was asking about.

I wasn't looking for a simplistic didactic response.

Ornello
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Joined: Thu Jan 19, 2006 9:49 am

Re: Digits Count

Post by Ornello »

Greg Winterflood wrote:
Ornello wrote:1:100 = 1+100
It didn't when I went to school in Pennsylvania.

Back then,

1:100 = 1 per 100 = 1 in 100 = 1+99 = 100, and

1+100 = 101

QED

No, 1:100 is 1+100.

If you want 100 parts, then it's 1:99.
Ornello wrote: If you want 100 parts, make it 1+99.
Are you saying that 1+100 = 1+99?

I imagine there might be a different linguistic convention among some photographers. That is what I was asking about.

I wasn't looking for a simplistic didactic response.
Paterson expresses their dilutions as "1+", which is perfectly clear. Anyway, a RATIO 1:100 is a total of 101 parts.

Keith Tapscott.
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Joined: Tue Jan 17, 2006 8:58 am
Location: Plymouth, England.

Post by Keith Tapscott. »

Ilford also use + rather than the ratio or :
Many find the former easier to understand and I wish other photo-chemical manufacturers would adopt the same.
If a photographer required 500ml of working strength solution for his/her processing tank and the dilution is 1+9, it is easy to calculate.
1+9 = 10.
500 divided by 10 = 50.
So the photographer requires 50ml of concentrate and then 450ml of water to make 500ml of working strength solution.
I`ve seen it on some photo-forums cited that 1:1 which is a typical dilution for D-76/ID-11 as meaning 1 part stock solution diluted with 2 parts of water. (Honestly). Kodak in the UK also used to use + instead of : but for some reason now use the ratio symbol. :o

Jim Appleyard
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Joined: Sun Mar 25, 2007 4:33 pm

Post by Jim Appleyard »

Anyway... by the time you get to 1:100, 1+100, 1+99 it's going to make very little difference.

I need to correct my previous post: I've never shot Efke 100, only the 25. However, the statement about Rodinal lasting a long time is still true and Efke 100 in Rodinal should still be a nice combo at the proper dev time. You can find the time right here at digitaltruth.

Greg Winterflood
Posts: 49
Joined: Tue Mar 27, 2007 2:11 pm

Post by Greg Winterflood »

Thanks Keith. Ornello's response to my question to Jim left me hanging as to how I should mix up my Rodinal. I guess a ratio of 1:99 or 1:100 probably doesn't make all that much difference in the big scheme of developing film, whereas if the ratio were 1:3 or 1:5 it would.

Maybe part of my confusion is that my inclination with liquids has been to read 1:100 as being one 'in' one hundred and not one 'to' one hundred. As part of my work I have to dilute drugs. I might have been led astray by the following: Adrenaline comes in a variety of concentrations, one of which is written as 1:1000, and read as 'one in one thousand'. It is actually 1mg of adrenaline made up to a total of 1mL, or 1000mg, of water. I guess the total weight might be 1001mg but have never thought of it that way, until now!

If one wants 1/10mg of adrenaline, one takes 1/10mL from the ampoule. Equally, many other dilutions are made "up to" a final round number volume so that aliquots are easily calculated. 1:10, 1:20 are read as 'one in 10, one in twenty' etc. I think a lot depends on which conventions one is used to.

My Kodak D76 has 'Dilution 1:1' printed on the package. I stared at that for a while before deciding that they meant 'half and half'. :lol:

For photography I'm used to the 1+9 system. 30mL +270mL makes 300mL for my 290mL Paterson Tank. I end up throwing 10mL away :roll:
Last edited by Greg Winterflood on Wed Apr 18, 2007 10:40 pm, edited 1 time in total.

Greg Winterflood
Posts: 49
Joined: Tue Mar 27, 2007 2:11 pm

Post by Greg Winterflood »

Thanks Jim. You must have written while I was writing, and got in before me.

Keith Tapscott.
Posts: 551
Joined: Tue Jan 17, 2006 8:58 am
Location: Plymouth, England.

Post by Keith Tapscott. »

Greg Winterflood wrote:
For photography I'm used to the 1+9 system. 30mL +270mL makes 300mL for my 290mL Paterson Tank. I end up throwing 10mL away :roll:
The 290ml of working strength solution in the Paterson tank is actually the "MINIMUM" requirement for each 35mm film to be processed, so no harm at all with that extra 10ml which would be erring on the safe side to ensure that the film is completely submerged in the processing solution. I use 300ml for each 35mm film and 500ml for each #120 size roll Greg if that`s of any use to you.

Greg Winterflood
Posts: 49
Joined: Tue Mar 27, 2007 2:11 pm

Post by Greg Winterflood »

I just found this comment on photonet.

"According to their curves for EFKE 100 in Rodinal 1:24, the film has an extended gradual toe and a curve that sweeps up gently......."

That seems so much neater :D

PS: the quote above came from some Norwegian researchers.
Last edited by Greg Winterflood on Fri Apr 20, 2007 7:10 pm, edited 1 time in total.

Greg Winterflood
Posts: 49
Joined: Tue Mar 27, 2007 2:11 pm

A Colon with Meaning

Post by Greg Winterflood »

Ornello wrote: Anyway, a RATIO 1:100 is a total of 101 parts.
I agree, that is true for a RATIO, but in Australia, when diluting we use the expression 1:100 as a RATE, not a RATIO. We read 1:50 as 'one in fifty' and not 'one to fifty'. That is, we read it as 1+49, whereas in the US it seems to be read as 1+50.

It appears that the meaning of that colon varies between different dialects of English, including Norwegian. :lol:

My whipper snipper calls for a 50:1 fuel/oil mix. I make that by first putting 100mL oil into a 5 Litre can and then I top the can to 5L with 4.9L fuel. I don't add 100mL of oil to an already full can.

Funnily, if we were talking about mixing cement I would read 1:3 as 'one bag of cement to three bags of sand'. That is, 1+3. We Aussies make a distinction between how the colon is read, depending on whether one is diluting liquids or mixing solids.

There has got to be a PhD in Linguistics in here, somewhere. :D

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