Pyrocat HD with Propylene Glycol

[donbga]

I've just mixed my first batch of PyroCat-HD part A with propylene glycol and quite to my surprise the color of the mix was a red wine color.

Is this normal?

 

[Tom Hoskinson]

Don, I mixed a liter of Pyrocat-HD part A in Propylene Glycol on 1/19/2006. My solution has a very slight yellowish tinge.

I suggest mixing a small amount of working developer and testing it with a 1" to 2" piece of exposed film.

 

[gainer]

I've just mixed my first batch of PyroCat-HD part A with propylene glycol and quite to my surprise the color of the mix was a red wine color.

Is this normal?

How much heat did you use? Oxidized phenidone, IIRC, is red. It doesn't take a lot of oxidation to change the color of combinations of the chemicals in Pyrocat HD. Pyrocat HD without sulfite should dissolve in glycol quite easily at about the temperature of hot tap water.
Your best bet is a test.
You might try the use of a small amount of ascorbic acid in place of the bisulfite. It works quite well in Pyrocat MC. About 2 grams should do the job. You can probably get by without the use of triethanolamine, which in Pyrocat MC is mainly for the purpose of free basing the metol.

 

[Ryuji]

How much heat did you use? Oxidized phenidone, IIRC, is red.

To be precise, when phenidone solution is pink/red or blue/green (depending on pH) it is still in the radical form, and it can be brought back to full working phenidone by adding HQ, catechol, pyrogallol, or ascorbate (color will disappear). Once phenidone is broken down by oxidation, it is irreversible and no amount of those agents will get phenidone back.

 

[donbga]

How much heat did you use? Oxidized phenidone, IIRC, is red. It doesn't take a lot of oxidation to change the color of combinations of the chemicals in Pyrocat HD. Pyrocat HD without sulfite should dissolve in glycol quite easily at about the temperature of hot tap water.
Your best bet is a test.
You might try the use of a small amount of ascorbic acid in place of the bisulfite. It works quite well in Pyrocat MC. About 2 grams should do the job. You can probably get by without the use of triethanolamine, which in Pyrocat MC is mainly for the purpose of free basing the metol.

Tom and Pat,
As far as I recall after dissolving the catechcol the color change occured. The glycol temeperature was about 180F. This was the temp of the gylcol when the remainder of the chemicals (phenidone and pot. bromide) were dissolved.

I'll test develop a sheet of film and see how that works.

 

[Tom Hoskinson]

Don, I checked my notes and I mixed my Pyrocat-HD 140 F.


Back in July of 2004 I mixed a stock solution of 125 grams Pyrocatechol in 500ml of Propylene Glycol, I mixed it at 200 F. The solution color is red/brown and it is still fully active.

Let us know how your test goes.

 

[sanking]

I've just mixed my first batch of PyroCat-HD part A with propylene glycol and quite to my surprise the color of the mix was a red wine color.

Is this normal?

Don,

When I first started mixing Pyrocat-HD in glycol I mixed at about 180-200F, and the solution turned red when I added the phenidone. However, it worked as expected so perhaps the coloration is due to food dye, as Pat Gainer has suggested in othre threads, and not to oxidation of the phenidone. In any event, I subsequently changed my working procedures to mix at 150F and now when I add the phenidone there is no change in color so my advice would be to just lower the mixing temperature.

Sandy

 

[Gerald Koch]

You can also add the ingredients to cold solvent whether it be glycol or TEA and then warm it just enough to dissolve them.

 

[gainer]

You can also add the ingredients to cold solvent whether it be glycol or TEA and then warm it just enough to dissolve them.

That is my usual approach. Of course, it helps to have the glycol warm enough to reduce its viscosity, but that's only about body temperature. This applies especially when TEA is the solvent. That stuff can freeze at about 70 F. It likes to supercool also.

 

[donbga]

Don,

When I first started mixing Pyrocat-HD in glycol I mixed at about 180-200F, and the solution turned red when I added the phenidone. However, it worked as expected so perhaps the coloration is due to food dye, as Pat Gainer has suggested in othre threads, and not to oxidation of the phenidone. In any event, I subsequently changed my working procedures to mix at 150F and now when I add the phenidone there is no change in color so my advice would be to just lower the mixing temperature.

Sandy

Sandy, Tom, Gerald, Pat, and Ryuji,

I just finished semi-stand developing a sheet of 4x5 film in a brand new Unicolor drum and the film looks swell! So the color change was inconsequential <sp?>.

I've been using PCatHd for about 5 years now and only until a few weeks ago did I have any problems with the developer.

Back in May I processed several sheets in a used Unicolor drum and had really wierd splotchy negs so I suspect I had some kind of contamination.

All is well now, thanks for your help
.

 

[gainer]

Another quick suggestion: add the catechol and phenidone before any heating. Adding the phenidone to a hot solution may cause the hot air near the surface to oxidize some of the phenidone. Glycol may have considerable water in it which may have considerable partial pressure at the surface of hot glycol. Hot water vapor and air are not so good for phenidone.

 

[gainer]

I just tried ascorbic acid for the sodium bisulfite in pyrocat HD. I used about 1/3 as much by weight. This ploy was used in a slightly different way to make Pyrocat MC. I think you will like it. Not that it's any better than the real Pyrocat HD, but that ascorbic acid is easier to dissolve in glycol than sulfite or bisulfite.

I don't know how it works in either th metol or phenidone case, but I am guessing that the phenidone-ascorbic acid or the metol-ascorbic acid combination, which need no sulfite for activity, generate enough silver to catalyze catechol or hydroquinone. Actually, I tested with hydroquinone, but I am dead sure it will work with catechol. The stain color will be somewhat different.

There is no need for TEA in the stock as the ascorbic acid seems to have no more effect on pH than the bisulfite did.

Now I have another 500 ml of a stock I can only use 5 or 10 ml at a time.

 

[donbga]

I just tried ascorbic acid for the sodium bisulfite in pyrocat HD. I used about 1/3 as much by weight. This ploy was used in a slightly different way to make Pyrocat MC. I think you will like it. Not that it's any better than the real Pyrocat HD, but that ascorbic acid is easier to dissolve in glycol than sulfite or bisulfite.

I don't know how it works in either th metol or phenidone case, but I am guessing that the phenidone-ascorbic acid or the metol-ascorbic acid combination, which need no sulfite for activity, generate enough silver to catalyze catechol or hydroquinone. Actually, I tested with hydroquinone, but I am dead sure it will work with catechol. The stain color will be somewhat different.

There is no need for TEA in the stock as the ascorbic acid seems to have no more effect on pH than the bisulfite did.

Now I have another 500 ml of a stock I can only use 5 or 10 ml at a time.

Patrick,

Thanks for the additonal tips for mixing PyroCat. I've compiled quite a few notes about the PyroCat variants and I do have a few questions about Pyrocat-P and PyroCat-M.

First of all it was noted in one of the many PCat threads that to use metol with glycol the metol needs a pH conversion to base. Any clues how to do that?

Second, being a person that likes to not fix something that isn't broke, what are the advantages of PCat-M and PCat-P over PCat-HD.

Since I have a densitometer and the BTZS software I suppose I could test all three and get a comparitive profile on each developer, however are there any pictorial advantages of one developer over the other? My use is primarily for large format sheet film with only occasional use of roll films.

Thanks,

 

[gainer]

In one of the many other threads or two or three, the use of TEA and a little bit of water to free the base of metol was described in detail. I don't have the details at hand, but the object is to calculate by the molecular weights of metol, TEA and water how much TEA and water is required, make a thoroughly stirred slurry out of those components, heat it somewhat and then add ascorbic acid and glycol to make the required volume. Since we must neutralize a sulfuric acid molecule and form a TEA-metol analog of a sodium methylaminophenolate we need 4 molecular weights of TEA for each molecular weight of metol along with 2 molecular weights of water.

 

[Tom Hoskinson]

Don, I've tested them all and they all give very similar results. IMO Pyrocat-MC appears to give slightly higher acutance and film speed than the others.

Pyrocat-P worked very well for me with continuous agitation and also worked very well semi-stand and gave high acutance.

 

[haryanto]

Pat,


what happen when TEA is not used in pyrocat MC with glycol

thanks

In one of the many other threads or two or three, the use of TEA and a little bit of water to free the base of metol was described in detail. I don't have the details at hand, but the object is to calculate by the molecular weights of metol, TEA and water how much TEA and water is required, make a thoroughly stirred slurry out of those components, heat it somewhat and then add ascorbic acid and glycol to make the required volume. Since we must neutralize a sulfuric acid molecule and form a TEA-metol analog of a sodium methylaminophenolate we need 4 molecular weights of TEA for each molecular weight of metol along with 2 molecular weights of water.

 

[sanking]

Pat,


what happen when TEA is not used in pyrocat MC with glycol

thanks

OK, I am not Pat Gainer, but perhaps can answer your question.

The Pyrocat-M formula was water based. Pat devised a way to mix metol with glycol in the Pyrocat-M formula, making it possible to have a very long life formula with all of the qualities of the Pyrocat-M formula. This invovles mixing a small amount of TEA and water, making a slurry, and then adding it to propylene glycol.

There may be other ways to effect the mix of metol in glycol, but the method Pat devised is very simple, and works great.

The small amount of TEA used to free base the metol plays little or no role in the characteristics of the developer since the carbonate Stock B solution works at a much higher pH than TEA.


Sandy

 

[haryanto]

thanks Sandy,

I just try to mixed pyrocat MC without TEA, I dissolved 2.5 gr of metol and 4 gr of Ascorbic Acid in small amount of water (to make it slurry), it's seems completed disolved, and then move it to warm glycol about 100F, and add 50 gr cathecol (and the make it 1lt) (takes time for catechol to dissolved completly)

I asked about TEA because from the result of my pyrocat MC, in tmax100 , EI 80, I've got very thin negative, i put my shadow in zone IV (i'm not test in densitometer because i dont have), it seem the shadow fall bellow zone IV, its about zone III, the highlight seems ok (the scene about zone IV and zone VIII)

I think that I have to set my EI around 50 or bellow that

I read in another thread about pyrocat MC that have good in speed


my B solutions is sodium carbonat, 200gr in 1 lt

working solutions is 1:5:100

I develop about 16 minute, 5 minutes presoak, 1 minute initial agitations, and each 3 minutes for the rest

standing dev, in tube (agitation by rolling the tube)

I've tried it with TMY with EI 200, it seems ok,

tha result is more accutance and sharper than result from my pyrocat HD, with recipe from your articles in unblingking eye, with 25 gr of metol

do you have any suggestions about this

thanks

OK, I am not Pat Gainer, but perhaps can answer your question.

The Pyrocat-M formula was water based. Pat devised a way to mix metol with glycol in the Pyrocat-M formula, making it possible to have a very long life formula with all of the qualities of the Pyrocat-M formula. This invovles mixing a small amount of TEA and water, making a slurry, and then adding it to propylene glycol.

There may be other ways to effect the mix of metol in glycol, but the method Pat devised is very simple, and works great.

The small amount of TEA used to free base the metol plays little or no role in the characteristics of the developer since the carbonate Stock B solution works at a much higher pH than TEA.


Sandy

 

[Claire Senft]

What an interesting and nice discussion this has been.

Gee, I do not miss Jdef one little bit.

 

[sanking]

I asked about TEA because from the result of my pyrocat MC, in tmax100 , EI 80, I've got very thin negative, i put my shadow in zone IV (i'm not test in densitometer because i dont have), it seem the shadow fall bellow zone IV, its about zone III, the highlight seems ok (the scene about zone IV and zone VIII)

Metol will definitely dissolve in water. Whether it stays in solution on being added to the glycol I don't know. I would think it would, but if it did not loss of film speed would be the anticipated result. However, the lack of TEA should not have any impact on film speed since the small amount used to dissolve the metol plays no role I am aware of in the developer action.

I can not understand the loss of film speed. My experience and that of everyone else who has commented is that the film speed of Pyrocat-MC is at least as high as that of Pyrocat-HD, if not slightly higher.


Sandy King

 

[Michael Kadillak]

What an interesting and nice discussion this has been.

Gee, I do not miss Jdef one little bit.

I completely agree. What a wonderful experience it is to be able to get back to intelligently discussing the substantive issues of a post without the typical distraction from Jdef we had to previously wade through. Sharing knowledge can be a pleasant activity and we all benefit from it. Pass it on....

Cheers!

 

[haryanto]

Thanks Sandy,

I will test it with EI 50 or 25 to see the result next week,

Yes Michael, what a wonderful world, discussions without any distractions, and sharing knowledge, nice to know u all

I completely agree. What a wonderful experience it is to be able to get back to intelligently discussing the substantive issues of a post without the typical distraction from Jdef we had to previously wade through. Sharing knowledge can be a pleasant activity and we all benefit from it. Pass it on....

Cheers!

 

[sanking]

Thanks Sandy,

I will test it with EI 50 or 25 to see the result next week,

Yes Michael, what a wonderful world, discussions without any distractions, and sharing knowledge, nice to know u all

Something that must be kept in mind is that there will be some variation in results when working with formulas that we mix ourselves, and this is because there is little or no uniformity in our materials. We acquire things like metol, phenidoine, pyrocatechin and ascorbic acid from a wide variety of suppliers, and from experience we know that there can be differences in the way these materiasl work, ranging from small to fairly significant, depending on our supplier.

So we should not expect the same level of consistency with our home-mixed formulas as when opening a pack of Kodak D76 or Xtol, where all of the ingredients are very carefully controlled by supplier and method of mixing.

Sandy King

 

[haryanto]

Thanks Sandy, that's make sense,

i bought cathecol from photoformulary, and the rest from local supplier

Something that must be kept in mind is that there will be some variation in results when working with formulas that we mix ourselves, and this is because there is little or no uniformity in our materials. We acquire things like metol, phenidoine, pyrocatechin and ascorbic acid from a wide variety of suppliers, and from experience we know that there can be differences in the way these materiasl work, ranging from small to fairly significant, depending on our supplier.

So we should not expect the same level of consistency with our home-mixed formulas as when opening a pack of Kodak D76 or Xtol, where all of the ingredients are very carefully controlled by supplier and method of mixing.

Sandy King

 

[sanking]

Thanks Sandy, that's make sense,

i bought cathecol from photoformulary, and the rest from local supplier

And some times little things make a big difference. For example, I have on hand a liter solution of Pyrocat-MC from the Photographers' Formulary, and a liter of Pyrocat-MC that I mixed myself. Both give *identical* results, except that the stuff I mixed has a much higher B+F in UV with long development times. Except for that fact, every measurment in Visual or Blue mode is the same, and across a family of curves ranging from four to sixteen minutes. Go figure!

Sandy