Mixing Vandyke chemicals

I just mixed the chemicals for the Vandyke process in the darkroom,

but something unexpected happened. While adding the silver nitrate

solution (slowly, a few ml at a time, mixing thorougly between each

addition) to the ferric ammonium citrate + tartaric acid solution, I

noticed that the resulting product precipitates, forming a cloud of

little greenish flakes that tend to deposit in the bottom of the

bottle. Stirring the mixture more doesn't seem to help.

Is this normal? Can I heat the mixture or something like that to help

with a proper dissolution? The recipe suggests to let the mixture rest

for a few days before using it. Will the texture be smoother by then?

Is my flaking solution useable or is it just wasted? If it is useable,

how does one evenly apply such a mixture on paper?

Greetings,

When mixing the VD sensitizer it should be done slowly and while constantly stiring. Once the precipitate forms, I don't know of any way to get it back into solution. You may want to try filtering it through a coffee filter and see if it works.

In the future you may want to consider mixing only small quantities, as mixed sensitizer does not keep well. I make the three "stock" solutions and keep them seperate until I'm ready to sensitize paper, then I only mix a small amount. Just enough to coat the paper for the particular printing session. By doing this, I have successfully kept solutions for 2 years and it becomes very simple when I'm ready to print.

Good Luck

Regards, Pete

Thanks, Pete. Thanks Dan, too - I had the chance to year your friendly reply between two failures/backups.

May I ask another question? The VD solution seems to apply well despite the cloud of small flakes, but I think I don't understand the procedures for development and fix very well. Basically, the picture exposes under the sun as indicated, and shows nice detail and density. Then, I put it in water for about 5 minutes. The image remains rusty brown and density builds up as expected, but lighter streaks from my brush strokes appear - even on double coated paper.

What really unexpected are the results from the fix stage. I fix in paper fixer, diluted normally (ie, dilution for RC paper) and the print really suffers from this dip. Yes, the print turns a nice deep brown in a second or two. But the print also becomes thin very quickly; the emulsion is washed from most bumps on the paper (relatively flat watercolour paper) and in a few instances, small colorless "bubbles" also appeared. The print is ruined, low density, low contrast, white spots. Washing for a few more minutes worsens the situation.

What am I doing wrong?

The fixer is also developer, and should be very dilute. A 2% solution of sodium thiosulfate is generally recommended. The best way to get this is to dissolve 20g Na2S2O3 (crystalline) in one liter of water. This will fix/develop two 8x10" prints or so. Under no circumstance should ammonium thiosulfate be used, nor should the concentration be over 5%.

Remember that this is NOT a silver halide print, the chemistry is totally different!

I'll offer a slightly different approach to making Van Dykes. Van Dykes have suffered a bad reputation when it comes to longevity and I believe this is in part due to inadequate fixing.

Using conventional strength fixing solutions is unadvisable. The silver in silver gelatin paper is suspended in the emulsion gelatin and is structurally much larger, hence the need for stronger fixing solutions and longer fixing times.

Your sensitized Van Dyke uses structurally smaller silver particles and they are not imbeded in an emulsion, so weaker and shorter fixing times are appropriate. While a 2% solution will work as Ole suggests, I beleive it is too weak; especially if you want the print to last for decades.

In addition to fixing, you should consider toning, though I don't recommend selenium. Gold, platinum and palladium all work excellently and if you tone the print prior to fixing, you will find that it barely bleaches back.

When you develop the print in water, you should change the water frequently and ensure the water is acidic. You want to make sure all the iron compounds are removed and some iron compounds are insolubel in an akaline environment. A pinch of citric acid to the first few changes of water will help. You should continue washing until the water runs clear.

After the wash, I recommend toning the print, then fixing in a 5-10% solution of sodium thiosulfate. I personally use a 10% solution and use two fixing baths, replacing the first bath after 6-10 8x10's; weak fixing solutions will exhaust quickly. After the fix I do a quick wash, then sodium sulfite hypo clear and a long final wash. This method has not failed me.

Regards, Pete

I forgot to mention that my favorite toner is palladium. The reason Van Dykes change "color" has to do with changes at the molecular level in the size of the silver. I have used full strength ammonium thiosulfate after toning in palladium and had very little change in color/density, indicating to me that the silver had been nearly completely changed. I did this as an experiment and don't recommend it.

Regards, Pete

Thank you, Pete, it all makes a lot of sense. The toning part is a bit frightening, however... I have selenium toner available and I've read on the Unblinking Eye that it can be used with success; the main trouble being the ammonium thiosulfate that is part of the solution. If I brew some recipe without ammonium thiosulfate, would that be OK?

I remember seing Gold and Pt/Pd toner recipes on the Photographer's Formulary, but they look complex and/or expensive to put to use... Will they exhaust or get contaminated with iron very quickly? Or will they last long enough to make the whole thing worthwhile?

Anyway, in the meantime, I'll try to produce a good, untoned VD print. That's the first step, getting the hang of the right exposure and of the washing/fixing procedure. I'll experiment with fancy toners when I have it right almost everytime.

Hi Philippe,

The main problem with selenium toners is thiosulfate. The most popular selenium toner, at least here in the USA, is Kodak rapid selenium toner (KRST for short.) KRST contains thiosulfate (fixer) so as your print is toning, it's also fixing and effectively "bleaching."

I've adopted Sandy King's toning method using the toner single shot. Toning using this procedure must be done in a flat bottom tray and you use a very minimal amount of toner; 50ml per 8x10. I know that sounds next to impossible, but the idea is to constantly tilt the tray in all directions allowing the small amount of solution to cover all areas of the print. Once you try it, you'll see just how easy it is. It's the only way I've been able to achieve consistency in toning from print to print.

I believe Sandy King has an article on Unblinking Eye that details the toner and the process, but it may be under his article on Kallitypes. Kalli's and Van Dykes share many similarities and the toners are interchangeable.

Everyone has their own preferences, but I do not like the color of a selenium toned Van Dyke, or Kallitype. On the other hand, a palladium toned Van Dyke looks remarkably like a true palladium print. In fact when done properly it would be next to impossible to tell, short of chemical, or spectrographic analysis. Platinum & palladium have always been "expensive" and people would counterfit prints a hundred years ago; they would sell Pt or Pd toned Kallis and Van Dykes as the genuine article. You use a much smaller quantity of the precious metal toning than you do making a true Pt/Pd print. You only need 20ml of a 20% solution of the noble metal to make 1000ml of toning solution.

Regards, Pete

Hello Pete. This is an image of my most recent trial. The density is still weak, but it shows a substantial improvement over my first (desastrous) trial.

I used ubiquitous vinegar rather that citric acid to lower the pH of the water; it seems to works all right. The fix was approx. 3-4% sodium thiosulfate and it still ate my prints pretty quickly, esp. the dark areas losing density. It may be my mistake. By habit, I used the fix plastic tray I use for silver gelatin prints and there might be some trace amount of ammonium thiosulfate in it. I'll try to be extra careful next time. Fixing time was about two minutes here. The paper was single coated.

Any thoughts? I checked the price of palladium and the two grams needed in your recipe would cost me 40 US dollars... Drugs look affordable in comparison! But then, the toning seems to be critical to the success of the process, so I'll think about it. How long do you fix?<div></div>

Hi Philippe,

Welcome to the idiosyncrasies of the Van Dyke process. In answer to your questions, no I don't think using your normal fixing tray will cause problems with using it for fixing Van Dykes. Just be sure to rinse/wash the tray well.

I suspect your lack of density may be the result of two variables: exposure and paper. First exposure, since the print "bleaches" in the fix, you must take this into consideration and expose the print more to compensate. As long as you don't expose too much, so as to solarize the shadows, you'll be O.K.

Paper is another matter. Van Dykes are attractive in that you can make them on almost any substrate, but that does not address what they will look like. This is a very subjective area and one that allows creative expression.

To address you desire for greater density, here are my suggestions. Use a "hot press" or "plate surface" paper. From the looks of your print, I suspect that you used a rough surface paper or cold press paper. These papers are nice and I like them very much, but they do not produce very good photos; not unless you're going for a certain form of artistic expression. Some papers that I have used and that work very well: Fabriano UNO, Arches Platine, Cranes cover 90lb., COT-320, Strathmore 500 series drawing paper Plate Surface, single ply and Staedtler Vellum.

The vellum is very nice and it's a paper I use often, but it's extremely thin, so you must use an appropriate backing when viewing. If light enters from behind the paper it will appear to lower the contrast and lighten the print.

Humidify the paper before coating. You don't want it wet, but if it were to stay in a room with a RH of 50% to 80% for several hours that would do the trick, then coat it immediately. After it's dry, expose it immediately.

My brief tests with double coating, did not yeild much improvements in Dmax, so I don't double coat. The real way to prevent significant changes in density during fixing are to tone the print prior to fixing. Thiosulfate is a silver solvent, so left unprotected, your print will lose density as it's fixing.

I hope this helps.

Regards, Pete

The same 4x5 negative as the picture posted three days ago, contact printed as a Vandyke once again. Density is much better, actually, it's too much because it wouldn't clear as much as I expected!

The main differences with the previous washed out image? First, the clearing bath was made with citric, rather than acetic acid. It seems to works much better. Second, the fixing bath was less concentrated, more in the 2-3% sodium thiosulfate range. A few drops of ammonia were added for a few prints; it seems to keep the image more rusty/red - it will turn darker brown in the ordinary fix. The final wash was made in water + vinegar.

The print was made on Strathmore series 300 cold press watercolour paper, as the previous one. Late this afternoon, I bought some Arches hot press very smooth watercolour paper, in a large sheet. I might give it a try tomorrow.<div></div>

You have better density with this one.

I've had mixed results with Arches hot press Aquelle. Prolonged wet times produced some uneven blotches that remained even after the paper was washed and dried. Other batches of the same paper were O.K. It's just one of those variables.

In your last image, if you want to keep the highlights clean, one thing to try is some dichromate in the wash water. Dichromate acts as a restrainer, hence its recommendation for contrast control. One word of caution, dichromate is a known carcinogen.

Regards, Pete

Dichromate is a restrainer when used in a developer or in the mix itself; in this case it's a bleach.

My reason for suggesting citric or oxalic acid instead of acetic is that the two former are strong chelating agents which will help removing the iron. Acetic acid does not help in this to any useful degree.

Just to get the chemistry right :-)

I've heard about potassium dichromate in the coating, but never in the wash water. The idea sounds interesting, though. I suppose we're talking about minute quantities, here? I had some success clearing an overprinted and too dense print by adding about 5 ml of potassium ferricynide (25% sol.) to about 2 litres of fixing bath . Actually, it was a bit too strong - it might be a good use for spent bleach from Kodak two bath sepia toner.

Here's one of today's prints on Arches, satin finish. I used a new foam brush to apply the mixture in very thin and even layers (two of them). Density and contrast are in the expected range (might not be obvious in the scan - these images are tough to scan) but the images are blurry. Further test will be required to determine if it's because too much of the mixture has been absorbed by the paper or because I checked the images too often, partly losing the negative registration.

I consider that I now have the process very much in control, the rest being a matter of fine tuning. I'll stop my experiments for now and save the precious chemistry for some fine prints when I finally get nice negatives from my new 8x10 camera. Thank you Pete, for all the help, and if you want to keep in touch, just drop by on my small photo community on http://photopixel.tilttek.com/ where you'll always be welcome. See you there Ole and thanks for the help, too.<div></div>

Though I mentioned dichromate, I really don't recommed it for Van Dykes. While some say that it is a contrastasting agent, IMHO it does nothing for improving the print when you need more contrast.

It will "clear" the highlights and in doing so effectively change the contrast, but it does not change the slope of the curve. Mid tones will still appear muddy and lack contrast.

My knowledge of the intracacies of the chemistry is limited, but I'd take Ole's word for it. I've seen Ole's postings on other forums about matters of chemistry and he appears to have a handle on it.

Regards, Pete