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

moodlover · Jul 30, 2015

Developing 120 b/w with D-76.

Reading the back of the D-76 packet for T-MAX100, it says develop 9 minutes for full strength or 12 minutes at 1:1 dilution. Why do we dilute and does it change the appearance? If I understand correctly, 1:1 is 250ml of developer and 250ml of water for 120 film, yes?

Edit: also confused about PROFESSIONAL T-MAX 100 (100TMX) vs T-MAX 100 Professional (TMX). These are the same films but one is an older version? Is that why the times differ from 6.5 mins to 9 mins respectively? I downloaded the Massive Dev Chart app but can't seem to figure out how to select 100TMX vs TMX, right now it's showing 6.5minutes at 20C as the develop time.

Sirius Glass · Jul 30, 2015

I have played the dilution game and the one shot game, but I get the smoothest tonal range, sharpness and repeatability with replenished XTOL.

Rolfe Tessem · Jul 30, 2015

I think that full strength was originally intended for large tanks with replentishment.

For most small labs and individual users, dilution 1:1 used as a one-shot is more economical. There are differences in appearance, but they are minor. Generally, the 1:1 dilution appears to have slightly higher acutance.

RobC · Jul 30, 2015

yes diluting changes the contrast and shape of the curver, especially the toe.

Also it can increase the size/sharpness of the grain as diluting with some developers reduces/stops the solvent affect of the developer on the grain.

But mostly people do it becasue they are tight with their money and/or they think they may discover the secret magic bullet by doing so.

Gerald C Koch · Jul 30, 2015

Diluting a developer has several effects. Probably the most obvious to the user is the increase of development time. Depending on the developer this can be rather complex. or high solvent developers like D-76 dilution increases sharpness and causes a small increase in film speed.

cliveh · Jul 30, 2015

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.

NB23 · Jul 30, 2015

I always go 1:0.

1:1 is for more acutance, and per Kodak's instructions, at least of 250ml stock has to be used per film, even for the 1:1 dilution. So there's no economy to be made by diluting.

If your monthly budget depends on dimes and pennies, then go Rodinal 1:50 with frequent agitations.

Rich Ullsmith · Jul 30, 2015

I don't think 500ml will cover a 120 reel.

My general understanding is the purpose of dilution pertains more to solvent developers like D-76, to dilute the sulfite and its effect on softening the emulsion. Supposed to be "sharper" by suppressing grain migration.

I dilute for economy. Keeps me in the darkroom longer with the door closed and music on.

pbromaghin · Jul 30, 2015

I switched to D76 from Tmax, which is very economical itself, after I was in a hurry and took a roll to a local lab. They did it in D76 and the negs were really nice - quite a bit sharper, it seemed. Replenishment is just one more step I can screw up.

And I'm cheap.

bernard_L · Jul 30, 2015

But mostly people do it becasue they are tight with their money and/or they think they may discover the secret magic bullet by doing so.

Think twice before second-guessing other people's motives. And take advice from the posts of cliveh ("very consistent results") and NB23 ("So there's no economy to be made by diluting").

R.Gould · Jul 30, 2015

When I use d76 I always use stock, it is by far the most ecconmical way, 1 litre of stock will develop 10 films, using the Ilford method, that is, add 10%after the first film, the 20.30.40, Etc up to 90% for the last film, and the last film is as good as the first, be it 120 or 35mm, for 120 at 1/1 you would get 4 films at the most, and for 35,,around 7 per litre,
Richard

Sirius Glass · Jul 30, 2015

Rich Ullsmith said:
I don't think 500ml will cover a 120 reel.

My general understanding is the purpose of dilution pertains more to solvent developers like D-76, to dilute the sulfite and its effect on softening the emulsion. Supposed to be "sharper" by suppressing grain migration.

I dilute for economy. Keeps me in the darkroom longer with the door closed and music on.

500ml will cover 120 reels in a Jobo tank and in 16 ounce stainless steel tank using one 120/220 reel.

markbarendt · Jul 30, 2015

There are several reasons that you will dilute a developer.

Primarily it is to save money. Diluting 1:1 will cut the cost in half compared to straight.

As I remember, D76 is slightly solvent. Using it full strength may result in slightly softer grain, diluting reduces the solvent effect making a slightly sharper Image. The word slight is very important, after using and experimenting with the developer for quite a while you might be able to spot the difference and use changes to your advantage. IMO There are so many other variables involved in getting the sharpness of any photo right that the rest of your system needs to be nearly perfect before you need to start worrying about this.

To the best of my knowledge dilution does not change the film curve (especially the toe) as long as the time is adjusted appropriately. (Compensation, limiting/restraining the highlight development, is allegedly affected by dilution and agitation.)

NJH · Jul 30, 2015

On your last point Mark this is claimed for using Perceptol diluted. I wonder which other developers exhibit this behaviour.

pentaxuser · Jul 30, 2015

NB23 said:
I always go 1:0.

1:1 is for more acutance, and per Kodak's instructions, at least of 250ml stock has to be used per film, even for the 1:1 dilution. So there's no economy to be made by diluting.

.

I don't understand your conclusion. The OP is talking about a 120 film which he says requires 500ml. If you use it at stock that is 500mls of D76. If you have to use a min of 250ml stock at 1:1 then this is 250 mls less of D76 needed compared to 1:0, isn't it?

pentaxuser

moodlover · Jul 30, 2015

RobC said:
yes diluting changes the contrast and shape of the curver, especially the toe.

Also it can increase the size/sharpness of the grain as diluting with some developers reduces/stops the solvent affect of the developer on the grain.

markbarendt said:
To the best of my knowledge dilution does not change the film curve (especially the toe) as long as the time is adjusted appropriately. (Compensation, limiting/restraining the highlight development, is allegedly affected by dilution and agitation.)

Well I'm confused now, which one is it?

moodlover · Jul 30, 2015

Rich Ullsmith said:
I don't think 500ml will cover a 120 reel.

Then what will? How come my paterson tank says 500ml on the bottom?

RobC · Jul 30, 2015

mine. how much is dependant on the developer. You will need more time in dev to get the contrast back and you may be able to get the curve toe back by using a slower speed/EI. In other words you need to experiment and/or measure using sensitometry to know whats really happening when you change dilution.

pentaxuser · Jul 30, 2015

moodlover said:
Developing 120 b/w with D/76.

Edit: also confused about PROFESSIONAL T-MAX 100 (100TMX) vs T-MAX 100 Professional (TMX). These are the same films but one is an older version? Is that why the times differ from 6.5 mins to 9 mins respectively? I downloaded the Massive Dev Chart app but can't seem to figure out how to select 100TMX vs TMX, right now it's showing 6.5minutes at 20C as the develop time.

I am puzzled. How old is your TMax100? It doesn't looked to have changed in a long time. Are you getting confused with the two versions of TMax 400? In Kodak F 4016 it lists the times for TMax 100 and the old TMax 400 and shows the 100 time as D76 stock 6.5 and the older TMax 400 as 8 mins. In the newer Kodak F-4043 which is solely devoted to the new TMax 400 it shows the new TMax 400 as 7.5mins

I can't see any changes from 6.5 to 9mins which relate to TMax 100

pentaxuser

MattKing · Jul 30, 2015

moodlover said:
Developing 120 b/w with D-76.

Reading the back of the D-76 packet for T-MAX100, it says develop 9 minutes for full strength or 12 minutes at 1:1 dilution. Why do we dilute and does it change the appearance? If I understand correctly, 1:1 is 250ml of developer and 250ml of water for 120 film, yes?

Edit: also confused about PROFESSIONAL T-MAX 100 (100TMX) vs T-MAX 100 Professional (TMX). These are the same films but one is an older version? Is that why the times differ from 6.5 mins to 9 mins respectively? I downloaded the Massive Dev Chart app but can't seem to figure out how to select 100TMX vs TMX, right now it's showing 6.5minutes at 20C as the develop time.

Dilution is for economy and to provide a slight increase of acutance, at the cost of slight increase in appearance of grain. Acutance is the most important component of what people sometimes refer to as sharpness.

As for the two versions of T-Max 100, the change happened in 2002. To see the difference in naming and packaging, see the final page of Kodak publication F-4016: http://www.kodak.com/global/en/professional/support/techPubs/f4016/f4016.pdf

The Massive Development Chart is like Wikipedia, except less accurate.

EDIT: F-4016 is Kodak's most recent opinion on the issue of developing times for the current T-Max 100. It specifies (for 20C/68F) 6.5 minutes for stock D76, and 9.5 minutes for D-76 diluted 1+1.

FURTHER EDIT: The current film is the Professional T-Max 100

Sirius Glass · Jul 30, 2015

Replenishment uses less developer per batch than diluting 1:1.

For one roll of 120 film or one 36-135mm roll uses 250ml of stock solution with an equal part of water for one shot development. So for a 5 liter batch of XTOL, will process 20 rolls of film.

Replenishment discards 70ml of developer per roll of film, so a 5 liter batch of XTOL, will process 71.4 rolls of film.

So exactly how is developer dilution cheaper?

gzinsel · Jul 30, 2015

I always understood 1:1 IS full strength. if you are 1+1 then thats 1:2. a total of two parts, one part being water , one part being developer.

Arvee · Jul 30, 2015

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.

So, put in context, you can successfully develop one 36 exp. roll or a roll of 120 in 250 ml in stock D-76. In a 500 ml tank you can do one 36 exp. 35mm roll and cover the film completely. But, you have to add another 250 ml water to develop a roll of 120 in order to cover the roll and you will need to extend developing time for the 1:1 dilution.

If you try to dilute 125 ml of stock with 125 ml of water (250 ml solution, enough to cover the roll) and develop a 36/35mm, you will most likely not have fully developed negs. Also, you cannot develop two 36/35mm rolls in a 500 ml tank using 250 ml stock plus 250 ml water. Negs are going to be thin.

Mr. Anchell goes as far as to strongly suggest using 350 ml per 80 sq. in. of film. Bottom line: Always use at least 250 ml stock solution per 80 sq. in. of film, then consider the volume needed to cover the film and adjust the developing time accordingly.

Note: it is also perfectly acceptable to dilute 250 ml stock with 250 ml water and develop a 36/35mm in a 500 ml tank to achieve the effects associated with 1:1 dilution with extended development time.

Okay, let the flames begin; someone out there has been using 125 ml stock for 80 sq. in. and hasn't lost a roll in 42 years!

DREW WILEY · Jul 30, 2015

I saw very little difference in curve shape or printing characteristics. Just a time adjustment.

Sirius Glass · Jul 30, 2015

gzinsel said:
I always understood 1:1 IS full strength. if you are 1+1 then thats 1:2. a total of two parts, one part being water , one part being developer.

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.

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

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