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Photo Forum / Film Photography / Darkroom / March 2004Dilution Question
Hi--What does it mean for something to be diluted 1:50? In terms of ounces and mililiters? What do the "parts" mean. In other words, of you say one part developer, 3 parts water, what does that mean in terms of ounces and mililiters? K > Hi--What does it mean for something to be diluted 1:50? In terms of > ounces and mililiters? What do the "parts" mean. In other words, of > you say one part developer, 3 parts water, what does that mean in > terms of ounces and mililiters? > > K First, 1:50 in _photography_ means one part of something in 50 parts of something else for a total of 51 parts. This is Kodak practice, in general chemistry 1:50 would mean one part of something in a volume totaling 50 parts. By _parts_ is meant equal measures, whatever they are. Parts can be ounces or milliliters, or grams or tons but each part is one unit. So saying to dilute a developer 1 part stock to 2 parts water would mean, for instance, using one pint of stock solution to two pints water (totalling 3 pints). Of course dilution implys liquid measure. "Parts" sometimes is used for solid measure but is a sloppy way of stating it.  Signature--- Richard Knoppow Los Angeles, CA, USA dickburk@ix.netcom.com > ... in general chemistry 1:50 would mean one part of something > in a volume totaling 50 parts. And I suppose 1:1 "would mean one part of something in a volumn totaling" one part. Is that correct? Dan > > ... in general chemistry 1:50 would mean one part of something > > in a volume totaling 50 parts. > > And I suppose 1:1 "would mean one part of something in a volumn > totaling" one part. Is that correct? Dan Well in the same container it is one part, of course its a bigger part than it was before you added the two smaller parts together to make one. ;-) SignatureLF website http://members.bellatlantic.net/~gblank > > ... in general chemistry 1:50 would mean one part of something > > in a volume totaling 50 parts. > > And I suppose 1:1 "would mean one part of something in a volumn > totaling" one part. Is that correct? Dan actually, it is correct :-) k On 2/19/2004 3:43 PM Dan Quinn spake thus: >> ... in general chemistry 1:50 would mean one part of something >> in a volume totaling 50 parts. > > And I suppose 1:1 "would mean one part of something in a volumn > totaling" one part. Is that correct? Dan I guess I have to 'fess up and eat crow for messing up and posting bad information. Richard's correct, of course: 1:1, in common photographic usage (which is WRONG, but never mind that), means one part X to one part water. In a just world, of course, this would be notated as "1+1", which is what it really means. And sorry to the O.P. (that's you, "missblueamerican") to adding to the confusion. Do you know now how to mix whatever it is you want to mix? SignatureIt's fun to demonize the neo-cons and rejoice in their discomfiture, but don't make the mistake of thinking US foreign policy was set by Norman Podhoretz or William Kristol. They're the clowns capering about in front of the donkey and the elephant. The donkey says the UN should clean up after them, and the elephant now says the donkey may have a point. Somebody has come out with a dustpan and broom. - Alexander Cockburn, _CounterPunch_ (http://www.counterpunch.org), 9/17/03 Kodak chemists, even way back then, understood scientific notation...They knew that mixing chemical A to water B in a 1:50 ratio in the laboratory, means 1 part A plus 49 parts B for a total of 50 parts... ---this is literally the first thing taught to chemistry lab 101 students, meaning they have to calculate how much A and how much B in order to get a final solution < say 2.5 : 36.4 > --- They also knew that the average photographer had zero chemistry lab training.. So, they adjusted either their stock chemicals, or the developing time, so that that Joe Photographer could stand in his kitchen and simply measure 1 ounce of A and 50 ounces of B, slop em together (totals 1:51 btw) and get consistent results... On the issue of 1:1 versus 1+1, examples: .. 1 + 1 means 1 ounce of A and 1 ounce of B, for a total of 2 ounces 1:1 means 0.5 ounce of A and 0.5 ounce of B, for a total of 1 ounce... The solution strength is the same, the total volume is different... denny "Dan Quinn" <dan.c.quinn@att.net> wrote in message > And I suppose 1:1 "would mean one part of something in a volumn > totaling" one part. Is that correct? Dan On 2/20/2004 5:09 AM Dennis O'Connor spake thus: > On the issue of 1:1 versus 1+1, examples: > .. [quoted text clipped - 3 lines] > > The solution strength is the same, the total volume is different... Um, I think you're needlessly confusing the issue with these examples. Both are exactly the same *dilution* (1+1), just different total amounts. I don't think the nomenclature "1:1" means what you said it does (0.5 + 0.5). According to photographic usage, "1:1" is essentially meaningless, as it means 1 part concentrate to 1 part *total solution*, which is the same as 1+0. I still say that manufacturers should be explicit about this and use the notation "1+n", as Ilford does, for example, to indicate mixing 1 part concentrate to n parts water. But it's a lost cause. SignatureIt's fun to demonize the neo-cons and rejoice in their discomfiture, but don't make the mistake of thinking US foreign policy was set by Norman Podhoretz or William Kristol. They're the clowns capering about in front of the donkey and the elephant. The donkey says the UN should clean up after them, and the elephant now says the donkey may have a point. Somebody has come out with a dustpan and broom. - Alexander Cockburn, _CounterPunch_ (http://www.counterpunch.org), 9/17/03 > > ... in general chemistry 1:50 would mean one part of something > > in a volume totaling 50 parts. > > And I suppose 1:1 "would mean one part of something in a volumn > totaling" one part. Is that correct? Dan I quick checked three general texts and a couple of texts dealing with analytical chemistry. I found no reference to ratios or dilution. Chemistry is a very exacting and methodically persued science. Solutions are sometimes percentage but more often normal, or molar. Although those are discussed there is no mention of ratio or dilution. Check your lab manual. Dan 1:1 means 1 part of one solution to one part of another solution. So in effect you have a 50:50 solution. 1:50 would mean 1 part of a solution to 50 parts of another solution for a total of 51 parts. >> > ... in general chemistry 1:50 would mean one part of something >> > in a volume totaling 50 parts. [quoted text clipped - 9 lines] >molar. Although those are discussed there is no mention of >ratio or dilution. Check your lab manual. Dan On 2/18/2004 10:10 PM missblueamerican spake thus: > Hi--What does it mean for something to be diluted 1:50? In terms of > ounces and mililiters? What do the "parts" mean. In other words, of > you say one part developer, 3 parts water, what does that mean in > terms of ounces and mililiters? Like they used to say, parts is parts. A "part" can be any measure. If you're using ounces, say, then 1:50 might mean 1 ounce (of concentrate) to 50 ounces *of total solution*. (That's where some of the confusion enters, by the way: it *doesn't* mean 1 part concentrate to 50 parts water, for instance.) Or to double the total amount, 2 oz. concentrate to 100 oz. total solution, and so on. Works the same way with milliliters, gallons or shot glasses. SignatureIt's fun to demonize the neo-cons and rejoice in their discomfiture, but don't make the mistake of thinking US foreign policy was set by Norman Podhoretz or William Kristol. They're the clowns capering about in front of the donkey and the elephant. The donkey says the UN should clean up after them, and the elephant now says the donkey may have a point. Somebody has come out with a dustpan and broom. - Alexander Cockburn, _CounterPunch_ (http://www.counterpunch.org), 9/17/03 > Hi--What does it mean for something to be diluted 1:50? In terms of > ounces and mililiters? What do the "parts" mean. In other words, of > you say one part developer, 3 parts water, what does that mean in > terms of ounces and mililiters? > > K It does not mean anything its either or. You could use 1-plus -49 or 1+50 at that ratio with little change. I would go with 1+49=50 You can use 1 oz +49oz's or you can use the ratio exactly the same in: ( ml ) as a smaller or larger increment. The end result is I alway mix the ratio to get the bigger number as a sum of the two parts that may be incorrect, but it works for me. SignatureLF website http://members.bellatlantic.net/~gblank > It does not mean anything its either or. You could use 1-plus -49 > or 1+50 at that ratio with little change. I would go with 1+49=50 That (1+49) is totally incorrect allthough there is little difference in this example. 1+1 or 1:1 in photography means 1 part something and 1 part something else (thus totaling 2 parts). It does _not_ mean 1 part of something in volume totaling 1 part. 1+50 with Rodinal means 1 part of Rodinal and 50 parts of water resulting 51 parts of working solution. The same applies to most other photographic chemicals. If you don't apply it correctly, you'll have troubles when trying to dilute 1:1, for example. IMHO for clarity it should allways be written A+B, not A:B. Severi > > It does not mean anything its either or. You could use 1-plus -49 > > or 1+50 at that ratio with little change. I would go with 1+49=50 [quoted text clipped - 12 lines] > > Severi Correct you are, at dilutions lower than 1+30 that is the way I do it, at 1+50/ it matters very little if you use 1plus 50 or 1 plus 49.... consistancy is what matters. Its easier to make an even increment, hence my rather differing method. At 1:1 there is little doubt, 1 part and 1 part. at 1: 7 I add 1part and 7 to make eight. At (1:2: 100 )- I add .....1part plus two parts plus water for a total volume of 100. which in my book is Less confusing and is consistant every time. My end result I always use even increments....as the graduates are designed to measure them. SignatureLF website http://members.bellatlantic.net/~gblank There is always a big confusion over this matter... Kodak uses 1:50 while Ilford uses 1+50. Both means the same, but I feel Ilford's way is more clear. At 1+50, it really will not matter very much, but at 1+2 it will make a significant difference. So read it as one part of something (cc, ounce, whatever) added to many parts of (usually) water. As one example, to mix 300cc of dev at 1+2: Divide 300 by 3 (1+2=3), so each part is 100cc. The result is 100cc dev, 200cc water. Jorge > Hi--What does it mean for something to be diluted 1:50? In terms of > ounces and mililiters? What do the "parts" mean. In other words, of > you say one part developer, 3 parts water, what does that mean in > terms of ounces and mililiters? > > K > As one example, to mix 300cc of dev at 1+2: > > Divide 300 by 3 (1+2=3), so each part is 100cc. > > The result is 100cc dev, 200cc water. And a general case: To mix V amount of dev at A+B: Developer (A) needed = V*A/(A+B) Water (B) needed = V*B/(A+B) In the example above A = 1, B = 2 and V = 300cc. Severi "maths nerd" S. >At 1+50, it really will not matter very much, but at 1+2 it will make a >significant difference. As long as you are consistent with yourself, that's all that really matters. I'm a fan of Xtol 1:3. But if you want to be precise, I actually use Xtol 1:2.82. (I fill 250 ml bottles with Xtol and then dilute with water to make 1 L working solutions. But, even though they're 250 ml bottles, they actually hold 262 ml if you fill them completely so there's no air when you put on the cap.) But it doesn't really matter just as long as your process is repeatable and you're happy with the results. -- Eric http://canid.com/ one part developer and 3 parts water means one part developer and 3 parts water. If you need 16 ounces of solution for your tank it's 4 oz stock and 12 oz water If you need 100 liters it's 25 liters stock and 75 liters water. -- darkroommike ---------- > Hi--What does it mean for something to be diluted 1:50? In terms of > ounces and mililiters? What do the "parts" mean. In other words, of > you say one part developer, 3 parts water, what does that mean in > terms of ounces and mililiters? > > K > Hi--What does it mean for something to be diluted 1:50? In terms of > ounces and mililiters? What do the "parts" mean. In other words, of > you say one part developer, 3 parts water, what does that mean in > terms of ounces and mililiters? > > K In photography, 1:50 means 1/51, in other words, a total of 51 parts, of which 1 part is the developer. The reason it is done this way is to make mixing easier: Just divide the total volume you need by the sums of dilution ratio components, and you have your volumes! So, if your dilution is 1+14, divide by 15! 600ml/15 = 40 ml So, if I want to dilute Rodianl 1:50 in a 32 oz tank, would that mean that I would want 4oz rodinal to 28 oz of water? would that be correct? thanks K No. 32 / 50 = .64 so the two- thirds oz mark on your graduate would be the closest. This is one reason most use the metric system in the darkroom. Your tank holds a little more than a liter, but if you measure with water you'll almost certainly find that 1 liter will cover your film with room to spare. That makes it easy-- 1000 / 50 = 20 cc (you will need a metric graduate). Charles Portland OR > No. 32 / 50 = .64 so the two- thirds oz mark on your graduate would be > the closest. [quoted text clipped - 3 lines] > almost certainly find that 1 liter will cover your film with room to spare. > That makes it easy-- 1000 / 50 = 20 cc (you will need a metric graduate). Not that it really maters, but if the the aim is 32oz, with a dilution of 1:50 you would need an amount of rodinal equal to: Rodinal = 32 / ( 50 + 1) For 1000ml it would be: Rodinal = 1000 / (50 + 1) Guillermo > So, if I want to dilute Rodianl 1:50 in a 32 oz tank, would that mean > that I would want 4oz rodinal to 28 oz of water? would that be > correct? No. :) You missed a good thread on this a bit earlier. What it means is 1 part Rodinal then add 50 parts water to make 51 ounces of developer. Unless Agfa follows their own convention. In any event, believe me that 1:50 or 1:51 ain't going to make a difference you will notice. What gets tricky is properly measuring small amounts of Rodinal. Use a very good, small graduate or an eyedropper type of measure. Pour water into the graduate to flush out all the Rodinal. It's all much easier if you use the metric scale with the 32 oz target. Make 1000cc and be happy. In article <37e9b963.0403121309.54b8b167@posting.google.com>, littlebabynothing1@yahoo.com (missblueamerican) wrote: > So, if I want to dilute Rodianl 1:50 in a 32 oz tank, would that mean > that I would want 4oz rodinal to 28 oz of water? would that be > correct? No. But to make it real simple: To 50 Oz water add 1 Oz Rodinal. Draw off 32 Oz and throw the rest away. Or reserve the rest, or make a larger total (working solution) so you don't throw away so much. The stuff keeps a really long time as a working solution if sealed properly. If you use 4oz Rodi and 28 Oz water you have a working solution with a ratio of 1:7..... Not what you want. _________________ Ready, Fire, AIM. Bruce Brooklyn, N.Y. > So, if I want to dilute Rodianl 1:50 in a 32 oz tank, would that mean > that I would want 4oz rodinal to 28 oz of water? would that be > correct? > > thanks > K No, and don't use ounce measures, use metric. Start with 1 litre (1000cc) as your target. Divide that by 51: 1000/51=19.60784313725490196078431372549 Or: 20 to make it easy. Place 20cc of Rodinal in a graduate, then fill with water to 1000cc. > > So, if I want to dilute Rodianl 1:50 in a 32 oz tank, would that mean > > that I would want 4oz rodinal to 28 oz of water? would that be [quoted text clipped - 12 lines] > > Place 20cc of Rodinal in a graduate, then fill with water to 1000cc. 1:50 would be 1020cc, not that it would make a lot of difference in this particular dilution. >>So, if I want to dilute Rodianl 1:50 in a 32 oz tank, would that mean >>that I would want 4oz rodinal to 28 oz of water? would that be [quoted text clipped - 12 lines] > > Place 20cc of Rodinal in a graduate, then fill with water to 1000cc. Or, so we don't have to measure down to the molecule, 20 cc Rodinal added to 1000 cc of water. > Or, so we don't have to measure down to the molecule, 20 cc Rodinal added to > 1000 cc of water. No, that's wrong! 20cc of Rodinal + 980 cc of water = total 1000cc. 1000 / 51 = 19.60784313725490196078431372549 Round 19.60784313725490196078431372549 up to '20'. Add 20cc Rodinal to the graduate, than add water to make up 1000cc. |
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