Help w/ dilution ratios for a newbie

[Will sameb]

So, when the dilution called for is 1:4, does that mean 1 unit of developer and 4 of water, or 1 unit of developer and three of water to make a total of four units?

I'm considering using Neutol Eco, which comes in 250 ml bottles, is supposed to be diluted 1:4, and has a capacity of 5 sq meters per liter. So do I mix a whole bottle with 750ml of water to get that 1 liter?

So, then, next I want to figure out wether I need to use the whole bottle:
if I want to develop say, five sheets of 5x7 paper, that's
.127 meters x .1778 meters = 0.0225806 square meters
If the capacity is 5 square meters, then 5/0.0225806=221 sheet capacity, so...no I don't need to use the whole bottle. I only need to mix 5/221 of the bottle, or x/250=5/221, x=5.6 ml

That's really inconvenient, and I'm not certain that I've calculated that correctly, anyway. So what kind of useful shortcuts do you use?

 

[Sirius Glass]

1:4 ===> 1 unit developer to 4 units water

':' is read as "to"

 

[MattKing]

Welcome to posting on APUG.
Looking at the web listing for Neutel Eco - http://www.adox.de/Photo/neutol-eco-2/ - I note that it offers a range of dilutions, but that they are expressed in the more clear 1 + manner.
In addition, it appears to me that the capacity figures are given for working solution, not concentrate. I'm not sure which way you were referring to them.
Here is how I would approach the problem if I were to print just a few 5x7 prints:
1) I would determine how much working strength developer I needed for the tray I was using. It might be something like 500 ml, which would require 50 ml of concentrate at the 1 + 9 dilution.
2) the data indicates that that quantity of 1 + 9 developer has the capacity to develop 2 square meters of paper (half of 4 square meters)
3) a 5x7 is about 1/40 of a square meter. So 500 ml of working strength 1 + 9 developer has the capacity to develop 80 such sheets.
4) once you have developed your five 5x7 prints, you need to either waste the remaining capacity, or attempt to store and re-use the developer at a later time. I don't know how long you will be able to store such an ascorbic acid based developer and have it continue to work well.

For such low volumes, you may want to try to use smaller volumes. Small trays can help, as can developing tubes.

Other developers are more likely to be long lasting, and therefore better suited to storing and re-using.

 

[Will sameb]

Thank you Sirius, thank you Matt.
I'm going to have to think through what you've written very carefully, Matt. I think I follow it pretty well, but certainly I'll need to do the math myself to fully understand it.

 

[MattKing]

The math is essentially the same as yours. You just took it to a few more decimal places and did a bit less rounding than I did.
When it comes to capacity questions, I prefer to leave lots of room for variance. I would approach it differently if I were doing the calculations for a higher volume, more mechanized process line.

 

[Sirius Glass]

1:4 ===> 1 unit developer to 4 units water

':' is read as "to"

OR
':' is related to the dreaded word "ratio" from that junior [middle] school terrorist named "Al-gee-bra".

 

[AgX]

1:4 ===> 1 unit developer to 4 units water

':' is read as "to"

No.
1:4 means: one fourth of the final solution

1+4 means: add 1 part to 4 parts

Though sometimes people writing instructions do not get that right themselves.

 

[Tony-S]

I wish everyone, especially Kodak, would switch to plus instead of colon. It is unequivocal and would eliminate confusion. This is not difficult.

 

[R.Gould]

what I have done, and I am sure many here is to divide the the total amount by the dilution, I.E. if you are using 500ml of developer at 1 in 4 the divide 500 by 5 and you get 100 so mesure 100 of developer add 450 0f water and you have your working strength developer,fixer stop etc

 

[Ian Grant]

1:4 means one part + three parts making a total of 4 aprts, so 1:20 means 1+19.

The only problem is Kodak use 1:4 to mean 1+4 which isn't at all logical, other companies make things much clearer rather than being ambiguous

Just to clarify the OP has used 1:4 in his post here, the Adox data sheet for Neutol Eco doesn't it uses 1+4 or 1+9.

Ian

 

[markbarendt]

When in doubt I google and hope to get to the original data from the horses mouth. In this case "neutol eco"

That found:
http://www.adox.de/Photo/neutol-eco-2/

Indicates there 1 + 4 or 1 + 9 so a bit clearer than the info you had.

Your 250ml stock solution will make either 1.25 liters of working solution or 2.5 liters depending on the dilution you choose.

Typically a tray can be filled with say 1.25 liters and used for a few sheets then put back into a bottle for storage until the next round of printing. Using a funnel with a screen to catch the bigger particle trash as you pour back to storage is prudent.

The other thing that is hidden in plain sight about dilution is that you can use many different ratios effectively, perfection in mixing is not required (though that can be helpful).

Adox has provided starting points for this chemical set at two different dilutions, 1 + 4 and 1 + 9, but you should understand that 1 + 3 would work fine too, you would just need less time in the tray. Similarly 1 + 5,6,7,8 or even 10,11 would work also with appropriate adjustments to the time in the tray.

You will find that a little extra time or a little less time in the developer will help certain prints, this is natural. You will find as you get closer and closer to the capacity of your developer you'll need to extend your times more and more.

What I'm getting at is that adjustments are/variability is the norm, don't sweat it.

 

[MattKing]

1:4 means one part + three parts making a total of 4 aprts, so 1:20 means 1+19.

The only problem is Kodak use 1:4 to mean 1+4 which isn't at all logical, other companies make things much clearer rather than being ambiguous

Just to clarify the OP has used 1:4 in his post here, the Adox data sheet for Neutol Eco doesn't it uses 1+4 or 1+9.

Ian

I wish that Kodak used the "+" notation rather than the ":" notation.
However, the Kodak written materials that accompany the notation are invariably very clear. So I think the takeaway is to always read the written instructions as well.

 

[Sirius Glass]

1:4 means one part + three parts making a total of 4 aprts, so 1:20 means 1+19.

The only problem is Kodak use 1:4 to mean 1+4 which isn't at all logical, other companies make things much clearer rather than being ambiguous

Just to clarify the OP has used 1:4 in his post here, the Adox data sheet for Neutol Eco doesn't it uses 1+4 or 1+9.

Ian

I wish that Kodak used the "+" notation rather than the ":" notation.
However, the Kodak written materials that accompany the notation are invariably very clear. So I think the takeaway is to always read the written instructions as well.

With Kodak, I follow the instructions and I have no problems. With the rest, I follow the instructions and I have no problems. I guess it is just RTFM again.

 

[Ian Grant]

I wish that Kodak used the "+" notation rather than the ":" notation.
However, the Kodak written materials that accompany the notation are invariably very clear. So I think the takeaway is to always read the written instructions as well.

Looking at some Kodak publications from the late 1940's and early 1950's the ":" notation is used in Eastman Kodak data whereas Kodak Ltd clearly state how many parts of developer etc and then water, There's nothing clear that the 1:2 etc means 1+2 in their modern now International data0sheets either, in fact they say "Typical Dilution (stock or concentrate) : Water" which can be read as a ratio, they definitely don't make things clear at all unlike other manufacturers.

The difference in notation is quite odd as the Eastman Kodak Research facility in Rochester, US like the Kodak Ltd Research facility in Harrow were both founded and headed up by Mees and his staff from Wratten & Wainwright.

Ian

 

[Peter Schrager]

Follow the instructions so you can actually learn what a developer can do....then do whatever floats Your boat
Happy holiday! !
Peter

 

[Ian Grant]

Just to really add to Kodak's own confusion of the use of the ":" or "+" symbol, in one Kodak Publication for KRST (Selenium toner) give the dilution range of 1 part toner with 3-19 parts water, but another just states 1:3 to 1:20.

Now which is correct 1:20 is 1+19 however 1:3 is not the same as 1+3, they really have got themselves in a mess

Ian

 

[MattKing]

If you look at any of the current |Kodak publications, they will either be completely specific in terms of words (to `1 part stock add 7 parts water) or they add an instruction after the dilution (not mixing) instruction that looks like this: 1:3 (stock:water).
At the top of the dilution column on the black and white film development matrix it says:
Typical Dilution (stock or concentrate: water)

 

[Sirius Glass]

As Matt pointed out the ':' means "ratio" as in the ratio of A to B. Hence 1 of stock to 3 of water and not 1 of stock to 1 of stock plus 2 of water. That what is meant is quite clear. Just as 1:19 is 1 of stock to 19 of water and that is the reason that 1 of stock to 1 of stock plus 19 water makes nosenseatall1 [no sense at all].


1Nosenseatall is a very hard to find photo chemical produced by the company Doznotexist Inc.

 

[Leigh B]

whatever floats Your boat

Must be a mighty small boat if it floats in 250ml of developer.

- Leigh

 

[MattKing]

It makes sense if you refer to the dilution process. If, however, you are analyzing the result, it doesn't make sense as a description of concentration. Unfortunately, that ":" nomenclature is used in other circumstances as a way to describe concentration.

 

[Sirius Glass]

Well since some think that A:B means A/[A+B] we should rewrite all books on photography and chemistry to satisfy them, but first we will have to reinvent mathematics starting with the number system and algebra and moving upwards to correct their mislearning the ratio concept back in the seventh grade. Dagnabit now where did that righteous weed go?

 

[Leigh B]

The notation A:B identifies a ratio of A to B.

If you're mixing something, A and B can be the volumes of the two constituents, with the total volume C implied.

However, if you're analyzing something, A:C commonly means (A) as a percentage of the total (C).
That's because the total volume C is known, but B is not known. B can be calculated only after volume A is determined.

- Leigh

 

[AgX]

The problem is as already indicated that the division sign is ambiguous:

-) "Make a dilution 1:3" likely means 1+2

-) "Mix the parts in a ratio of 1:3" likely means 1+3

 

[AgX]

Luckily these concentration issues in many cases do not matter.

Much worse is that milliard/billion issue

 

[Huub]

Luckily these concentration issues in many cases do not matter.

With paper developer... When developing film they do matter.

I would make enough solution to have plenty of liquid in my developing tray to work confortably, probably using the 1+9 dilution. Unless i have a second dark session planned within a few days i tend to use the develper as a one shot. It doesn't store very well, even in full bottles and older working stock solutions can take quite a whiile to reach the max black of the print