Why do we dilute? Full strength vs Dilution 1:1

[pentaxuser]

I always understood 1:1 IS full strength. .

If 1:1 is full strength i.e. stock then what does the second 1 represent? We are back to the 20 year sticky on the big question: Is 1+1, meaning 1 part stock to 1 part water, the same as 1:1 meaning a ratio of 1 part stock to 1 part water?

" Marshall Kane", says the railway clerk, " Pierce, Colby and Ben Miller have been down at the depot for the last two hours waiting for the noon train".

Leaving town is not an option. The matter has to be settled and unfortunately without the help of Tex

pentaxuser

 

[Sirius Glass]

1:1 is one chemical to one water resulting in two units of quantity. Stock is 1:0. That is how chemists, engineers, and mathematicians use the terminology.

1:1 can be written as 1+1 but most professional will not use the later notation because the understand the notation of 1:1.

By the way, no one uses 1:0. The proper term for that is Stock Solution or Stock.

 

[Dali]

1+0 = 1:1 = no dilution.

 

[eddie]

1:1 (or 1+1) means one part stock to one part water.
1:2 (or 1+2) means one part stock to two parts water.
Etc., etc.

 

[Sirius Glass]

1+0 = 1:1 = no dilution.

No
1+0 is NOT equal to 1:1
1:1 is NOT equal to no dilution

But 1+0 is equal to no dilution

You can disagree all you want but you will STILL BE WRONG!

 

[Sirius Glass]

1:1 (or 1+1) means one part stock to one part water.
1:2 (or 1+2) means one part stock to two parts water.
Etc., etc.

eddie understands it.

 

[RobC]

1:1 (or 1+1) means one part stock to one part water.
1:2 (or 1+2) means one part stock to two parts water.
Etc., etc.

+1 ( although in this instance that might confuse some people )

 

[Bruce Osgood]

1:1 is NO CHANGE, or stock, one to one. It is not one plus one.

1:2 is one plus one, or 1 to 2. It is not 1+2, never was.

The : is not a plus sign. It is a ratio sign.

The second number is the product of thr ratio.

 

[RobC]

1:1 is NO CHANGE, or stock, one to one. It is not one plus one.

1:2 is one plus one, or 1 to 2. It is not 1+2, never was.

The : is not a plus sign. It is a ratio sign.

The second number is the product of thr ratio.

what is : a ratio of when its 1:1 then? If 1:2 means 1+1 then its talking about stock ratio to water. So it follows that 1:1 means stock ratio to water unless you're really trying to tell us that when we use 1:1 we change the meaning of whats on the right hand side from water to stock. But that would be nonsense. A ratio is a comparison of two different things so 1:1 and 1+1 mean exactly the same thing.

 

[Sirius Glass]

1:1 is NO CHANGE, or stock, one to one. It is not one plus one.

1:2 is one plus one, or 1 to 2. It is not 1+2, never was.

The : is not a plus sign. It is a ratio sign.

The second number is the product of thr ratio.

Evidently you do not understand ratios. A:B is defined at the ratio of A to B, not A is the product of A to B. Therefore 1:1 is one stock to one water. It is not NO CHANGE. Like it or not a basic chemistry book will tell you that. Also this was covered in Algebra I. The world of mathematics also agrees with that definition.

You state that "The : is not a plus sign. It is a ratio sign." and as such it is the ratio of reagent to water. Therefore one reagent [or stock solution] to one water and that by definition can be neither NO CHANGE [because it does change the reagent or solution] nor can it be stock.

Again you can disagree but you will be STILL be wrong and every science and math will prove you wrong. Still not believe it? Look it up on the internet rather than shooting from the hip.

 

[Bruce Osgood]

If I understand your questions correctly, then the first number is an amount of developer to be diluted. The second number is total of both A & B. In the case of 1 to 2 it would be 1+1=2 and expressed as 1:2. Again, 1:1 is unchanged or stock or even neat.

 

[Sirius Glass]

If I understand your questions correctly, then the first number is an amount of developer to be diluted. The second number is total of both A & B. In the case of 1 to 2 it would be 1+1=2 and expressed as 1:2. Again, 1:1 is unchanged or stock or even neat.

If you want to believe that OK, but that is not the definition that mathematics, chemistry and photography uses.

 

[RobC]

If I understand your questions correctly, then the first number is an amount of developer to be diluted. The second number is total of both A & B. In the case of 1 to 2 it would be 1+1=2 and expressed as 1:2. Again, 1:1 is unchanged or stock or even neat.

No, 1:1 is a ratio which says 1 of stock to 1 of water. Its relative expression. Thats how ratios of anything are expressed. The size of one side of the : compared to the other side. If you are using stock only it would be 1:0 but when there is nothing on one side there is no ratio to express so you would just say stock.

 

[Sirius Glass]

From:https://en.wikipedia.org/wiki/Ratio

[h=2]Notation and terminology[/h] The ratio of numbers A and B can be expressed as:[4]

• the ratio of A to B
• A is to B (followed by "as C is to D")
• A:B
• A fraction that is the quotient of A divided by B:
  

The numbers A and B are sometimes called terms with A being the antecedent and B being the consequent.[citation needed]
The proportion expressing the equality of the ratios A:B and C:D is written A:B = C:D or A:B::C:D. This latter form, when spoken or written in the English language, is often expressed as

A is to B as C is to D.​

A, B, C and D are called the terms of the proportion.
A and D are called the extremes, and B and C are called the means. The equality of three or more proportions is called a continued proportion.[5]

Ratios are sometimes used with three or more terms. The ratio of the dimensions of a "two by four" that is ten inches long is 2:4:10. A good concrete mix is sometimes quoted as 1:2:4 for the ratio of cement to sand to gravel.[6]
For a mixture of 4/1 cement to water, it could be said that the ratio of cement to water is 4:1, that there is 4 times as much cement as water, or that there is a quarter (1/4) as much water as cement..
Older televisions have a 4:3 aspect ratio, which means that the width is 4/3 of the height; modern widescreen TVs have a 16:9 aspect ratio.

 

[Bruce Osgood]

I believe what you say is Kodak's understanding as well. I do not think Ilford agrees.

It's not relative in that it is conditional. 1:1 is always 1:1. 1 to 1 is not a change. It is static. Stock. A one to one ratio is not one to zero. The right side number is the same or greater than the left side number, not smaller.

 

[mklw1954]

As single 120 stainless reel requires 14 oz. to be covered, which is equal to 0.41 liters, or 410 ml. For a plastic tank and reel, the volume required is usually printed on the tank or lid.

Kodak's D76 data sheet explains the effect of using the stock solution vs. using 1:1 (one part stock solution and one part water).

 

[markbarendt]

Geez, I got confused by all the opinions offered! Diluted or not, 250 ml of stock D-76 is required for each 80 sq. in. of film. Period, per Kodak's spec.

Per Kodak j-78

If you use D-76 Developer diluted 1:1, dilute it just before you use it, and discard it after processing one batch of film. Don’t reuse or replenish this solution.
To extend the useful capacity of D-76 Developer diluted 1:1—when processing two 36-exposure rolls in a 16-ounce tank—increase the recommended time by about 10 percent.

16oz = 473.176475ml

So 2 rolls per 473.176475ml per Kodak

 

[markbarendt]

https://en.wikipedia.org/wiki/Ratio

 

[K-G]

1:1 is NO CHANGE, or stock, one to one. It is not one plus one.

1:2 is one plus one, or 1 to 2. It is not 1+2, never was.

The : is not a plus sign. It is a ratio sign.

The second number is the product of thr ratio.

+1

Karl-Gustaf

 

[Ian Grant]

I agree with Bruce and Karl, Kodak;s terms 1:1 & 1:3 are confused, they used to be more accurate and say I part developer and 1 part water etc for dilutions.

Older Kodak reference books say D76 should be used at Full strength and not dilute and recommend replenishment. I used ID-1/D76 for many years replenished it's very consistent much more economic and you get higher quality results.

When we made up a fresh tank full no-one wanted to be the first to use it, there's a very apparent improvement once the developer is seasoned, acutance (sharpness) improves, grain is finer and tonal range improves - better shadow details.

It's easy to replenish on a smaller scale but these days you're better using Xtol which is self replenishing with fresh stock developer rather than a separate replenisher.

Ian

 

[Dali]

https://en.wikipedia.org/wiki/Ratio

The dilution ratio page is more appropriate to this thread.

 

[removed account4]

hi OP

if you have a few rolls of film, why not do a little experiment ?
... expose the film and process each one with a different dilution / time.

i'd take advice, even from the brightest of chemist/photographers as a starting point
because it is through their way of developing ( water, controls, agitation ) not the way *I* process my film.
all the times listed for development, from what i understand, are the same thing, a set of starting points.

good luck !
john

 

[RalphLambrecht]

Using a developer at full strength often means that you may reuse it and add a replenisher. This is fine, but in my opinion does not provide a consistent development as a one shot 1:1, 1:2, 1:3, etc. may do. I prefer 1:1 and discard, which gives very consistent results.

+1

 

[Terry Christian]

Bruce Osgood is correct. The ratio is the proportion of parts to the whole. Fractions are also ratios: 1/4 means one part out of four parts.
Thus, 1:1 means that one part out of a total of one is stock (1+0). 1:2 means one part of a total of two parts is stock (1+1).

 

[RobC]

The dilution ratio page is more appropriate to this thread.

So it seems its like art. People to take it to mean whatever they like. And there was me thinking maths wasn't like that and was totally objective. Mind you, there are no references or citations in that dilution ratio page so it could have been written by a misguided photograper for all we know.

When is a ratio not a ratio? Answers on a postcard to Santa Claus, The North Pole.