View Full Version : The Trouble With Xtol

William D. Lester
13-Feb-2001, 09:06
I have seen a number of comments in this forum about the so called Xtol failure. I have experienced it a couple of times in the past, but it wasn't something th at I was watching for and I attributed it to something that I might have overloo ked - overuse of the developer or maybe it wouldn't last as long as Kodak said. I stopped using it for a while. The problem is that is can be a nice developer a nd I wanted to give it another try. I decided to buy enough 1 litre packages tha t it would come still in the carton as shipped from Kodak. I ordered a dozen pa ckages which arrived as a full box ( 10 Pkgs ) and 2 loose units. I felt that I would have control over the product that way. It would be fairly fresh and not s itting around on someone's shelf for a year or so. The first package worked perf ectly. I thought I might be on to a system of control and my confidence was buil ding. On the weekend I shot a couple of rolls of film and mixed a fresh litre of developer. The film was so under developed that the negatives were unprintable. I was shocked. I developed the second film in some ID-11 and it was perfect. I threw the rest of the Xtol ( the remaining full box ) in the garbage. I don't ha ve any films that I want to take another chance on. I am convinced that there is a problem with the product. Too bad. When it works, it works well. I'm going ba ck to and sticking with Ilford's product. I hope Kodak reads this.

John H. Henderson
13-Feb-2001, 09:45
I haven't had any problem with XTOL except for like the second batch I had ever made. It underdeveloped. I attributed it to using it immediately after mixing. Since then, I have always made sure that I mixed some hours before I use it, and haven't had a problem since.

Paul Minkus
13-Feb-2001, 10:15
I have heard many good reviews of XTOL and wanted to try it. I have experienced XTOL failure a couple of times recently. Once it was a near total failure where the negs where mostly undeveloped and the images appeared faded, streaked, and clouded. I have developed more than a thousand rolls of film in my 30+ year interest in photography. I have screwed up many a roll due to my own mistakes, but I can't stomach ruining valuable film that I have high expectations for through some mysterious developer malfunction. I was aware of the problems with XTOL through various forums like this and was therefore ultra-careful and processed the film with all the posible XTOL pitfalls in mind. I am disgusted by XTOL and have dumped it and the idea of ever using it again. I feel like I have been betrayed by it! I will use the old standards that behave in a consistent predictable way. Paul

John Sarsgard
13-Feb-2001, 10:41
I have tried everything, and read about every temperamental developer I haven't tried. I decided that when you do something in total darkness and have to trust time, temperature, and agitation...and whoever made the developer...you are better off going with the tried and true and cutting your losses. I have gone back to D-76. I can no longer remember what problem(s) I was trying to solve in trying all the other stuff. To entertain myself I experiment with papers and toners. I can always do over what doesn't work with them. I'm sure there are other always reliable film developers as well, but I can no longer think of any reason to risk precious images playing with film developers.

Daniel Taylor
13-Feb-2001, 10:55
Xtol has great potential. I have started processing at 72F degrees in hopes that the extra energy will stand off the gremlins lurking in each package. with Xtol, I never know what to expect when I pop the lid off the developer tank. no failures in a long while, but I am not convinced that it will not occur once again when I least expect it.

as mentioned, TMax in Xtol is worth the efforts to prod Kodak into investigating this problem.

Pete Andrews
13-Feb-2001, 12:06
It seems to be fairly common knowledge that Ascorbic acid or sodium ascorbate is unstable in solution, but no real explanation other than simple 'oxidation' is given anywhere.I still think the cause of failure could be attack by a natural yeast or enzyme, possibly carried in the gelatine of the film emulsion. It would be informative if the pH of a failed Xtol bath could be measured, and compared to a fresh one.If some sort of biodegradation is taking place, then there ought to be a detectable by-product, such as a gas or an alcohol. This might give an early warning of an unusable Xtol batch.Could anyone using Xtol, and who has access to a pH meter, measure a failed batch if they come across one?

13-Feb-2001, 18:36

Ascorbic acid is simply a very active chemical and is easily oxidized, not only in solutions, but also in air! So store your chemicals (powders) in a dark brown bottle/container with wax seal (if you can) in your fridge. Ascorbic acid and sodium ascorbate work as a buffer (weak and cheap), which maintains your developer's pH at a relatively stable value (pH = 8.2). If ascorbic acid is oxidized, then the buffer will lose its "buffering" capability. As a result, the pH of your developer will shift (go towards alkaline because sodium hydroxide is a much stronger base) and your film will be "cooked". You don't need a pH meter to determine pH, a roll of pH paper (less than a dollar) will last you a long time. To avoid those failures, one should have freshly prepared xtol, temperature should be stable, and as Dan pointed out, the water used to prepare xtol should be high quality. Distilled water is a good start. I used to prepare my ascorbic buffer with Milli-Q water. Finally if you see your developer becomes yellowish in datlight, do not use it. It's so bad! Cheers,

14-Feb-2001, 00:12
I sure wish someone would try Mytol and see if it has the same qualities and/ or problems http://www.jetcity.com/~mrjones/mytol.htm

Pete Andrews
14-Feb-2001, 06:05
Hi Geoffrey.The oxidation problem is common to all developers, since they're reducing agents, but the problem with Xtol seems to go beyond this. People are describing sudden and catastrophic failure of this developer, sometimes in 24 hrs.The Sodium Ascorbate in Xtol isn't simply there as a buffer, it's the main constituent of the developer. It exhibits a superadditive or reactivation effect in conjunction with Phenidone. The quantity of Phenidone in Xtol is insufficient to give anything but a very weak, soft image on its own, so the Ascorbic acid content is vital to its working.

Further to my previous post, it might be worth measuring the specific gravity with a hydrometer as well.

Robert Bedwell
14-Feb-2001, 07:08
I have been using Xtol almost exclusively for over three years now to the tune of about one 1-litre package a week. I have had one incident of failure with a 5 litre package. I have had to return perhaps 6 packages to the dealer that part B had "clumped." I think it is important to use distilled water in both the mixing and the dilution process. Kodak specifically states that you should use at least 100ml of stock solution per roll of film. This may be the source of some of the problems reported by Xtol users. Also, I am careful to make sure the mixed solution is properly stored. The bottom line, in my opinion, is that this developer requires more careful handling than any that I have ever used but the time and trouble is worth it.

Dan Montgomery
14-Feb-2001, 14:27
What am I doing right? I love Xtol! Perhaps us happy users are less likely to write but after reading the above,thought I might add some perspective. I mix it with our (decent) city water, make sure to stir constantly while mixing part B, and store it in a brown, plastic accordian bottle with no air. Develops ten Tri-X or HP5+ 8x10's at normal times then add 15% more time for the next five, then discard. Send me your unsed Xtol!

William D. Lester
14-Feb-2001, 16:20
Thanks to everyone who contributed an answer. You're comments have been welcome. I think that there is a problem with Xtol and I hope that Kodak resolves it. I'm sure they will. It seems to be one of the finest developers that I personally have used. The problem is that right now I can't rely on it and I value the film I shoot too much to loose it like this. I am aware of the number of comments about using distilled water. Some friends of mine do and 20 years ago I did also. But for a long, long time I have used good old Detroit River water (from the Canadian side) and it seems to have worked just fine. I'm going to stick with ID-11 for a while.

Geoffrey Chen
14-Feb-2001, 16:24
Dear Pete,

First of all, could you please kindly explain to me your definition/meaning of the sentence you used in your previous posting "It exhibits a superadditive or reactivation effect in conjunction with Phenidone" in plain chemistry terms, especially the word "superadditive"? Secondly, I do not believe that xtol could cause a "sudden and catastrophic failure" during a developing process. If a failure should take place, then something bad has already happened to the xtol developer you use before the developing process even began. For example, if the developer is prepared using hard water (calcium content exceeds 200 ppm), you will be ended up with a "catastrophic failure" (your xtol developer will become bad in minutes). So use distilled water or filtered water to prepare your xtol stock and keep some vitamin C handy. For another example, if you dilute the xtol stock too much, you will be ended with another "catastrophic failure". So make sure you use 3.5 oz xtol stock per 8x10 sheet and don't dilute the stock more than 1:1, as a guidence. This is how chemistry works.

The following is my guess on xtol because Kodak has not yet published their trade secrets, therefore please correct me if I'm wrong. Phenidone (1-phenyl-3-Pyrazolidone, C9H10N2O, molecular weight about 162) is used as a "catalyst" (not a real catalyst but like a catalyst) to speed up the image developing process, in which silver halide is converted into metallic silver. Without Phenidone, you can still develop your image, but the process will be very long. Grant Haist once said in his famous "Modern image processing" vol. 1 (1960) that one can develop images in "polluted lake abd river water, old red wine, citrus fruit juices, and even human urine". He, however, did not say how long it should take! In short, all you need is a salty soup!!! Now let's back to Phenidone. In order for Phenidone to work properly, it requires an optimal ionic strength (total salt concentration) and pH (Hydroquinone, for example, requires pH = 9 at 72 C to work properly. Lower pH will result in a "very weak, soft image". You can experiment this by adding some Coke to your D-76 developer). Ascorbic acid and sodium ascorbate fill in here perfectly. They are low in toxicity, very cheap, and environmentally sound. I still think that they mainly work as a buffer and also contribute to the ionic strength needed by Phenidone. I bet my one cent that you can replace ascorbic acid and sodium ascorbate with TRIS or TRICINE balanced with LiOH and use Lithium sulfite to fill the required ionic strength. To further stabilize the developer, add 0.5 % glycerin and 20 mM DTE. It will have a much longer shelf life even in daylight. Warning: DTE smells very bad!

Finally, It's said that xtol is a fine Kodak developer if you know how to use it properly. I have heard many many successful stories. If someone likes to play with developer formula(s), here's a place you can get chemicals and advices: Photographer's Formulary (800-922-5255)


Charlie Stracl
14-Feb-2001, 21:04

I'm no chemist, but "superadditive" is a commonly used term in regards to photographic developers. It describes the effect where 2 developing agents combine to produce greater development effect than would be expected by the simple sum of their effects(synergy). It applies to the combination, not the individual agent. Thus, metol is super-additive with hydroquinone, and vice-versa, but you don't call either super-additive all by itself.

Some developing agent combinations are sub-additive, some super- additive, and others simply additive.

With super-additive agents, if I understand right, two agents both act to reduce the silver, but one of the agents acts with the reduction by-products to regenerate the other agent. It's as if one agent acts as a catalyst and a developing agent, which is probably what is going on.

In any case, upredictable failure of Xtol appears well documented, and it's a shame Kodak doesn't have the scientists around to analyze and fix the problem, if possible, since the developer has many advantages when it works. For me, I don't want to mess around with something that even appears to lack repeatability.

John O'Connell
15-Feb-2001, 09:11
I never bothered trying XTOL. Sounded intriguing, heard reports about it being an occasional nightmare, remembered that John Cage said you don't use random chance operations to cross streets or pick mushrooms, and promptly decided on other compensating developers.

That said, I made the right choice if XTOL is unstable at 200 ppm levels of hardness. I've worked in cities whose water averaged 180 ppm and I don't need a developer which makes my photography more difficult than it has to be already.

John H. Henderson
15-Feb-2001, 09:47
Again, I've only had problem with one roll of 35mm film with XTOL when I used it immediately after mixing - the same batch of developer worked perfectly the next day. But also, the first two packages of XTOL I ever bought had the smaller packet of chemicals clumped. Not knowing any better, I figured that was normal. Since those two packages, I have never seen it clumped again. So now I think it abnormal. Anyway - I always mix on distilled water and wait several hours after mixing to use it, and haven't had a problem.

15-Feb-2001, 14:36
Hi Charlie,

Thanks for your explanation of the word "superadditive". I have no problem understanding the word per se, and I have heard and used it for at least 15 years. My trouble is to see ascorbic acid being classified as a superadditive. A quick search of NEXES database, I found Xtol under US Pat. # 5,756,271. Its major components are: part A [sodium sulfite anhydrous, diethylene-triamine-pentaacetic acid (pentasodium salt), sodium metaborate, 4-hydroxymethyl-4-methyl-1- phenyl-3-pyrazolidone] and part B [sodium sulfite anhydrous, sodium metabisulfite, sodium ascorbates]. Kodak's main claims are : the developer has no restrainer, highly buffered, not sensitive to bromide, no skin poisoning, and friendly to the environment. Ideal working condition: pH 8.2 @ 72 F.

Now let's look at individual chemicals: 4-hydroxymethyl-4-methyl-1-phenyl-3-pyrazolidone is a derivative of Phenidone, and it shares many physical and chemical properties with Phenidone. Kodak says it's more stable in solution. It's white powder, very low solubility in water, starting to dissolve in water at 175 F/ 80 C. Soluble in alkaline solutions. Chemically, it's sensitive to oxidation. Sodium sulfite is used as a preservative to inhibit oxidation of 4-hydroxymethyl-4-methyl-1-phenyl-3-pyrazolidone. In addition, sodium sulfite is also an important solvent for silver halide. Sodium metaborate is used to prevent gas generation. The function of diethylene-triamine-pentaacetic acid (pentasodium salt) is not said, but it could be used as a chelator to prevent trace heavy metals from reacting with 4-hydroxymethyl-4-methyl-1-phenyl-3-pyrazolidone. Sodium bisulfite is used in part B to prevent ascorbates from being oxidazed by increasing acidity. Sodium carbonates are commonly used in developers to buffer pH. Because of its drawback of generating "pinholes" on film (by depositing tiny air bubbles on film surface), they are not used in Xtol. Instead, sodium ascorbates are used. They are perfect buffer candidates.

I don't know whether ascorbic acid is a superadditive to 4-hydroxymethyl-4-methyl-1-phenyl-3-pyrazolidone. It's true that ascorbic acid has its chemical potential to regenerate 4-hydroxymethyl-4-methyl-1-phenyl-3-pyrazolidone at pH 9 and above. But remember that the Xtol working pH is 8.2. Chemistry literature indicates that, at pH 8.2, ascorbic acid is INACTIVE in regenerate 4-hydroxymethyl-4-methyl-1-phenyl-3-pyrazolidone. Enough said.

I called Kodak Imaging products Group regarding my Xtol questions. The responses are very simple: "it's a good thought" when asked about ascorbates and "it's your water" when asked about those failures.

Pete Andrews
16-Feb-2001, 05:27
Hi again Geoffrey.My immediate reaction on hearing that Ascorbic acid was actually being claimed as a developing agent was to dismiss the idea as new-age hype. For a start, it isn't based on a benzene ring, and doesn't have the hydroxyl, or amine radicles common to all conventional agents.However, some research showed that one of its major known properties is a strong affinity for halides, which it combines with readily.Since I can find no official documentation of the processes taking place in an Xtol type developer, this is my hypothesis:The development site on the crystal grain is initially 'attacked' by the Phenidone (or derivative). Once the reduction process has commenced, and free halogen ions are released into solution, then the Ascorbate takes over the process, and rapidly converts the rest of the grain to metallic silver by removing the halide from the reduction products, and maybe taking part in some further reaction with the by-products of the Phenidone-Agx reaction. The strong anti-oxidant properties of Ascorbic acid are also well known, and it's even possible that the Phenidone is completely regenerated. (I'm not sure why you say that it needs to be above pH 9 to act as an anti-oxidant, one of the listed incompatabilities with Ascorbic acid is strong alkalis)Anyway, that's the reason that I cited it as being superadditive with Phenidone.

There is an Xtol substitute called 'Mytol', which apparently gives identical results. The full formula of that developer is published. It contains 'plain vanilla' Phenidone, and no chelating agent. Without the Sodium Ascorbate content, it exhibits the weak development expected of a Phenidone and alkali only developer. When the Sodium Ascorbate is added, the activity is normal, despite the pH actually being reduced. Case proven, I think.

Michael A. Covington
3-Jun-2001, 13:02
Actually, the formula of Xtol, or something very close to it, is published in U.S. Patent 5,853,964 (available free of charge from www.uspto.gov).

I have had several instances of clumping or difficult dissolving but no failure to develop (yet!). At the same time I can't afford to lose even one roll of film, so I'm wary.

HC-110 is my old standard. It's not a perfect developer, but it is very, very reproducible and the syrup keeps forever.

Michael A. Covington
3-Jun-2001, 13:07
Another query. Those of you who have had underdevelopment problems -- Have you been using diluted Xtol? I use it full strength.

John Hicks
3-Jun-2001, 14:16
> Another query. Those of you who have had underdevelopment problems Have you been using diluted Xtol? I use it full strength.

I've now had exactly one Xtol failure, and it was enough. The developer worked fine, then a couple days later was essentially dead with no color change or any other hint that it went off.

It had been mixed with distilled water, was well within Kodak's stated storage life, and was used at a 1:1 dilution with plenty of stock. The film was Delta 3 200.

Most reported failures I've seen, however, involve TMX and usage at a dilution higher than 1:1.

Michael A. Covington
20-Jun-2001, 10:51
Here's a method for testing Xtol to make sure it hasn't lost its strength. I plan to experiment with this.

You need a scrap of photographic paper that does not have the developer incorporated into it; Multigrade IV or Polymax will work fine.

In full room light, put a drop of Xtol concentrate on the paper. After 30 seconds, put another drop on it in a different place. After another 30 seconds, wash them off. (For permanence, you can fix and wash the scrap of paper.)

You should have a mid-gray spot and a black spot. I plan to do this several times and see how well it works as a test of developer potency.

I'm thinking of starting an Xtol resource page similar to my HC-110 page at www.covingtoninnovations.com/hc110. If I do, I'll put a reference to it there.

Michael A. Covington
22-Jun-2001, 10:47
What are some alternatives to Xtol? The advantages of Xtol that I'd like to preserve are, in order:

(1) With T-Max films, less highlight contrast than with T-Max or HC- 110 developers. That is, more of an S-shaped rather than an upswept characteristic curve.

(2) Fine grain and full speed.

(3) Ease of use. Xtol was supposed to be a very easy-to-dissolve powder; it doesn't actually work out to be much easier than any of the competitors, and in general I don't like working with powders. That's why I don't standardize on D-76 or ID-11.

(4) Known development times for a lot of films. I normally use T-Max 100 but occasionally have a roll of almost anything.

So... What do people recommend? HC-110, taking care not to overdevelop, is not bad. What else is out there that might be better in some way? Ilfotec DD-X? Edwal TG-7 or FG-7? (And what is Ilfosol-S like?)