The ambigity of "dilution 1:3"

What is "dilution 1:3 "

In medicine and chemistiry, dilulion 1:3 means dilute one part concentrate with solvent, such that the final volume is 3 part.

In some photography formularies, however, "dilution 1:3" means

dilute one part of concentrate with 3 part of water.

<p>

In the first case, the concentration is 1:3 or 33%

In the later case, the concentration becomes 1:4, or 25% of original.

<p>

IMO, the usage in some photography writing ( dilute 1:3 as add 3 part water to 1 part stock ) is incorrect

I agree - it causes confusion. Typically, in photography 1:3 means 1

part of whatever is being diluted and 3 parts of the solvent (i.e.,

you end up with 4 parts of final solution). Richard Henry suggested

using 1+3 etc as a less confusing alternative but old habits die

hard, I guess.... Cheers, DJ.

a dilution of 1:3 (one to three) means mix one part concentrate with

three parts water. it doesn't mean mix a 33% solution.

I've always read 1:3 as "one to three", which is fairly unambiguous.

One part of concentrate to three parts water. In other words, a 25%

solution. You sometimes see 1:1 written as a dilution, and this

doesn't make any sense other than as a 50% solution.

We darkroom denizens have always used some terms in our own special

way, like referring to chemicals as "chemistry". Years ago I adapted

the 1+3 convention, as have most photo chemical manufacturers.

Many photographers do use dilute 1:3 sloppily as 1 part concentrate

+ 3 part water, one even may see such sloppy usage in some Kodak

documents<p> But when it comes to serious instruction, Kodak has being

very precise, for example on Tmax developer bottle " Add one part

concentrate to 4 part water ", they don't say dilute 1:4

<p> Ilford instructon is also precise, they say " 1 part concentrate

+ x part water "

<p> The problem with the usage with slopy photographic ussage of

"dilute 1:3" as "dilute 1 part to 3 part water" is that it is

in conflict with the usage common in chemistry and medicine

where a dilution of 1:3 means one third strength. Before photography

was born, chemist had already mixing solutions for many many

centuries.

<p> Dilution 1:3 indicate a degree of thiness. (See New Oxford

Dictionary of English )

<p> Agfa also say " add one part concenrate to 15 part of water"

<p> So IMo, dilute 1+3(water ) is better than dilute 1:3

<p> The most strict difintion must be the one followed by chemists

and pharmacists: dilute 1 part (of A )with solvent to make 3 parts

<p> Because 1 part in volume of A plus 1 part of same volume of

solvent does not always result in twice the volume of original, some

times it may be more, some times it may be less. <p> A good example

is 100 ml of ethanol plus 100 ml of water yields much less then 200

ml of dilute, if you want really 1:2 strength, more water is

needed, otherwise, the dilition is more than half strength. <p>

Therefore, in

chemistry and medicime, the quatity of solvent is not important,

sometimes you don't even know what it is, and don't need to know.

The important thing is to control the final volume of the dilution.

<p> In old days, photographic formular was quite strick, they told

you to add such and such chemicals in 600 cc of hot water, disolve

completely, then ADD WATER TO MAKE 1000 CC. Why not prepare 1000 cc

of hot water outright ? Because, the resulting developer will be

more then 1000 cc.

<p> Fortunately, in photography dilution mostly refers to acqueos

solution, and 1+ 3 = 4 parts.

Since I am a chemist, I can speak from experience. A dilution

written as 1:3 has always been 1 part of A mixed with 3 parts of B.

What may change from time to time is the units of measurement. For

example 1:3 may be followed with v:v which specifies the unit of

measurement is volume of each part or 1:3 may be followed with wt:wt

which specifies the unit of measurement is weight. I would like to

know the specific example where 1:3 means 33%. I've never seen in

college or industry.

There is nothing wrong if everything is clearly specified like

stock:water = 1:1 or stock:final volume = 1:2.

However people tend to assume former in many photographic contexts

without making it explicit.

<p>

I prefer notation 1+(n-1) for 1/n concentration. However, in this

context one usually restrict n to positive integer, although dilution

makes sense for any proportion (real number) between 0 and 1,

inclusive.

<p>

It is a bit inconvenient when most formulae are published in metric

units some tanks and packaged chemicals assume Imperial system.

Developers like HC-110 and Ilfotec HC usually specify dilution in

1:(n-1) or 1+(n-1) fashion where n is a power of 2. At the same time,

some film tanks come in metric scale.

For example, mixing 1+63 for 1 liter tank requires 15.625 (or 15 +

5/8) ml concentrate.

<p>

In my personal records, partly because the capacities of my tank

and print slot processor are specified in metric volume units,

I am shifting into notation like concentration

0.015 and calibrate time and temperature accordingly. (1+63 dilution

would be 0.015625 concentration although maintaining five significant

digits is not practical nor useful) In some cases

I need to make 473 ml working solution - I can simply multiply 0.015

and 473 to get approximately 7.1 ml concentrate and WTM 473 ml (yes

number comes out messy this case).

<p>

<p>

Many formulae still begin with some fraction of water and after

dissolving everything another water to make the final specified

volume. Either way, when precision is important chemists specify in

molarity or other appropriate units, and in most photographic

applications generally moderate requirement for precision does not

neccesiate that kind of units.

It has never been ambiguous. : refers to a ratio. Not necassarily a

percentage. For every x: part in the final formula there are :x parts

for it to be added to. And a ratio in the spoken language is

pronounced- to. So 1:3 is pronounced and meant to be 1 part of

something added "to" 3 parts of something else. It turns out to be a

25% dilution but that is secondary to what the ratio is. Not ambiguous

at all. Pretty simple. James

Mathematically 1:3 is a ratio, which usually associated with

mulitplication or division, to interpret 1:3 as 1+3 is incorrect.

<p> 1:3 = 2:6 =3:9 = 0.33333

<p> To interpret "a RATIO of 1 to 3" as "1 plus 3" is clearly

incorrect.

Because 1:3 =2:6 =0.33333 never = 1+4

<p> I much prefer the usage dilute 1 part stock + 3 part water

Further, according to the Oxford Dictionary of English,

the word dilution means a degree of dilute. Given as example"

" An antidote was administered at dilution 1:50"

My understanding is, in English usage, a dilution of 1:50 means

the concentration of the final solution is only 1:50 or 1/50 of

the original.

<p> Further, 1 ml of the dilution, has a strength of only 1/50

of the original antidote.

<p> From liguistic standpoint, the correct interpretation of

"dilute 1:3" is dilute to a RATIO OF 1:3

Not dilute to 1+3.

<p>

The following is a definition of dilution

<p>

"Dilution : The effect of changing the concentration of a solution by

the addition of more solvent.

A dilution of 1:10 means the addition of 9 volumes of the solvent to

1 volume of the original solution.

The resulting solution is one tenth as concentrated as the original."

<p>

Taken from:

<p>

http://www.nico2000.net/DataSheets/glossary.html

If 1:3 means mix only on part stock to 2 parts water to make a final

mix, then what would 1:1 mean?

What is USD to CD$ at 1: 1.5 ? Us dollar = 1+1.5 =2.5 Canadia

$.

What is a map of 1:100,000 ? 1+100,000 ? absurd !

<p> To interpret 1:N as 1+N is out right wrong !

<p>The subject title of my question is "Subject: The ambigity

of "dilution 1:3"

<p> All I need to to is to find ONE definition, I have suceeded.

It IS ambiguous !

In dilution, there are THRREE volumes, A the orginal concentrate,

B the volume of solvent, C the final volume

<p>

In dilute 1:3 only TWO volumes are specified, 1, and 3

one of these two must be the original stock, not necessary 1

<p>

Dilute 1:3, UNSPECIFIED, has three possible meanings

<p>

1 part stock add solvent to make 3 part final

1 part of stock + 3 part of water

<p>

1 part of water + 3 part of stock

Dan, what is macro 1:1 means ?

<p>

Meticulous technical instructions all avoid "dilute 1:3"

<p>

They specified clearly 1 part CONCENTRATE + 3 part water

<p>

You never see Ilford or Kodak use "dilute 1:3" style sloppy,

instruction on their bottles.

Martin Tai is quite correct. Photographers have been using incorrect

notation for 50 years or more. Not that it matters all that much, so

long as we all know what we mean. Richard Henry explains this in his

book "Controls in Black and White Photography".

<p>

I don't want to hear any more smart-ass comments about people whose

native language is not English. That message and any like it will be

deleted.

Comments about non-native speakers of the English language are

not "smart-ass". Usage of language is based on generally accepted

and contextual meaning, not necessarily the literal or out-of-context

rules established in a dictionary that has a reputation for not being

current on legitimate "popular usage". If photographers have been

using this notation for 50 years, then it is about time the Oxford

dictionary is changed (with respect to the usage of dilution in

photography). Like you say, everyone knows what is meant, and

therefore the entire subject is nothing more than beating a dead

horse.

Martin said: "But when it comes to serious instruction, Kodak has

being very precise, for example on Tmax developer bottle " Add one

part concentrate to 4 part water ", they don't say dilute 1:4."

<p>

That is not entirely accurate. In accordance with the generally

accepted PHOTOGRAPHIC use of the term dilution, Kodak uses 1:3 to

mean that 1 part solution is mixed with 3 parts water. They clarify

it the chart heading, but Kodak does use the generally accepted

photographic notation. See the web site:

http://www.kodak.com/global/en/professional/support/techPubs/e103cf/e1

03cf.pdf

In the post immediately above, the last part of the web reference did

not post correctly. it should be: e103cf.pdf

1:28, 1:29, 1:30 OR 1:49, 1:50, 1:51... (my most common dilutions)

Startling different results, I don't think so! I can't measure it

accurate enough to tell you what the end result was. The end result

is what matters and I'm happy with that.

Although I do not agree with Martin Tai's argument 100%, as far as I

can tell his main problem is the notation and is separate from

someone's measurement accuracy and insignificance of the difference it

makes in resulting image quality.