Brown Ammonium ferricyanide - turns pale greyish blue-Ned help

[hol571]

here are the 2 step wedge type images I have. I don't remember the exact exposure times, but I haven't left anything out in the sun for longer than 15mins

 

[fgorga]

Another basic question to you.. How long can I store the solution A and B in glass bottles? What's the best way to store them?

Thanks
Nithya

Both solutions are quite stable and not light sensitive. Only the mixture is light sensitive.

I store them at room temperature in a closet in tightly closed clear plastic bottles.

They should keep for months easily... probably years. That said, I've never gone longer than five or six months before using them up.

The ferric ammonium citrate tends to grow mold on the surface. When that happens, I just filter the volume I need just before I use it.

 

[Niths]

In brown bottles and away from light and heat, they should last months, if not longer, indefinitely even - as I understand. I only make small quantities that last me 2-3 months at a time so I have not experienced longer times. If you do not have brown or amber bottles, wrap them in aluminum foil or black plastic or something opaque.

Thank you Niranjan! I have used aluminum foil to cover.. And I used the old batch of solution today to make some prints.. I followed your advise on the exposure time.. I washed them within 2 hours and it came out pretty well.. However a couple of them got foggy immediately after I exposed.. Attaching an image of the print before wash.. What could be causing the fog?

Nithya

 

[nmp]

Thank you Niranjan! I have used aluminum foil to cover.. And I used the old batch of solution today to make some prints.. I followed your advise on the exposure time.. I washed them within 2 hours and it came out pretty well.. However a couple of them got foggy immediately after I exposed.. Attaching an image of the print before wash.. What could be causing the fog?

Nithya

What do you consider to be the fog in the picture?

 

[Niths]

here are the 2 step wedge type images I have. I don't remember the exact exposure times, but I haven't left anything out in the sun for longer than 15mins

View attachment 255948
View attachment 255949

Thank you so much for this.. I guess my emulsion doesn't work that well.. Today I tried a 1 hour and 30mins exposure and the colors looked dark soon after the hydrogen. Peroxide wash.. However now when I see, it's faded quite a bit.. Not sure why. May be I have to leave it longer..?

 

[Niths]

What do you consider to be the fog in the picture?

In the center of the image.. Do you see a light grey blob? That's what I mean by fog.. Don't know what you call it in your cyanotype terminology!
It stays even after wash..

 

[nmp]

In the center of the image.. Do you see a light grey blob? That's what I mean by fog.. Don't know what you call it in your cyanotype terminology!
It stays even after wash..

OK, I see. How did you coat the paper? Did you pour the whole quantity in the middle and then brush it out all over?

Can you please share the final print that goes with this.

 

[Niths]

OK, I see. How did you coat the paper? Did you pour the whole quantity in the middle and then brush it out all over?

Can you please share the final print that goes with this.

No I didn't pour.. I used a brush to brush it all over..

 

[nmp]

No I didn't pour.. I used a brush to brush it all over..

I am not sure what could have caused it then. There is obviously some variation in the sensitizer coverage where the blob is. It looks to me to be lighter than the the rest - I would expect that the blue density would be lower there than the rest. Is that so?

Other than that the print at this stage looks very much normal. Lightest where there is minimal exposure, turning green with some exposure, then on to blueish with some more and finally turning gray with maximum exposure where there is no coverage by the feathers. The last stage is called "solarization" where some of the Prussian blue gets photo-reduced to Prussian white making it revert from the blue tone to more neutral one. When you are exposing in the Sun, you can judge the correct exposure by looking at the shadows of the print and allow the exposure to proceed just past where the shadows start looking lighter/grayish than the mid-tones. This Prussian white gets oxidized back to Prussian blue as you leave it in air or by hydrogen peroxide treatment.

The term "fog" has a specific meaning in this context, coming from the conventional darkroom world - it relates to density (in this case blue) in the print where there is no exposure. For example, if you just coated and dried a piece of paper with cyanotype chemistry and washed it out without giving it any deliberate exposure and it turns a shade of blue, it is said to have "fogged."

:Niranjan.

 

[Niths]

I am not sure what could have caused it then. There is obviously some variation in the sensitizer coverage where the blob is. It looks to me to be lighter than the the rest - I would expect that the blue density would be lower there than the rest. Is that so?

Other than that the print at this stage looks very much normal. Lightest where there is minimal exposure, turning green with some exposure, then on to blueish with some more and finally turning gray with maximum exposure where there is no coverage by the feathers. The last stage is called "solarization" where some of the Prussian blue gets photo-reduced to Prussian white making it revert from the blue tone to more neutral one. When you are exposing in the Sun, you can judge the correct exposure by looking at the shadows of the print and allow the exposure to proceed just past where the shadows start looking lighter/grayish than the mid-tones. This Prussian white gets oxidized back to Prussian blue as you leave it in air or by hydrogen peroxide treatment.

The term "fog" has a specific meaning in this context, coming from the conventional darkroom world - it relates to density (in this case blue) in the print where there is no exposure. For example, if you just coated and dried a piece of paper with cyanotype chemistry and washed it out without giving it any deliberate exposure and it turns a shade of blue, it is said to have "fogged."

:Niranjan.

Thank you so much Niranjan for the detailed explanation. It helps a lot in understanding the exposure time.. I am going to try another batch over the weekend.. Will post the results.

Thanks
Nithya

 

[Niths]

I am not sure what could have caused it then. There is obviously some variation in the sensitizer coverage where the blob is. It looks to me to be lighter than the the rest - I would expect that the blue density would be lower there than the rest. Is that so?

Other than that the print at this stage looks very much normal. Lightest where there is minimal exposure, turning green with some exposure, then on to blueish with some more and finally turning gray with maximum exposure where there is no coverage by the feathers. The last stage is called "solarization" where some of the Prussian blue gets photo-reduced to Prussian white making it revert from the blue tone to more neutral one. When you are exposing in the Sun, you can judge the correct exposure by looking at the shadows of the print and allow the exposure to proceed just past where the shadows start looking lighter/grayish than the mid-tones. This Prussian white gets oxidized back to Prussian blue as you leave it in air or by hydrogen peroxide treatment.

The term "fog" has a specific meaning in this context, coming from the conventional darkroom world - it relates to density (in this case blue) in the print where there is no exposure. For example, if you just coated and dried a piece of paper with cyanotype chemistry and washed it out without giving it any deliberate exposure and it turns a shade of blue, it is said to have "fogged."

:Niranjan.

Hi Niranjan,

Here is the print from today's batch before wash.. If you can see the blobs are back! Don't know what's causing it.. In the first and last prints, you can see the spots which are lighter blue after wash. The prints are now drying and will send a pic..
Can you also tell me why I see some discoloration around the white areas of the print.. Which is again light blue after wash.. Is it because it's over exposed? I kept it for about 3 hours as last time with 1 hour the blue wasn't deep enough..

Nithya

 

[nmp]

Hi Niranjan,

Here is the print from today's batch before wash.. If you can see the blobs are back! Don't know what's causing it.. In the first and last prints, you can see the spots which are lighter blue after wash. The prints are now drying and will send a pic..
Can you also tell me why I see some discoloration around the white areas of the print.. Which is again light blue after wash.. Is it because it's over exposed? I kept it for about 3 hours as last time with 1 hour the blue wasn't deep enough..

Nithya

The blobs - they are much larger than the one before. Probably something to do with how the sensitizer is getting distributed and absorbed on the paper. Is the paper bowing or bulging in the middle when you start coating. How thick is the paper (in gsm or lb weight)?

About the white spots, no idea but again it is most likely due to sensitizer coverage - may be wetting problem, perhaps some spots on the paper have less affinity for water than the rest (due to contamination or defect in the paper) so the sensitizer is deficient in those areas. Watch the coating while you are brushing and look if the sensitizer flows evenly. If it is not wetting the paper in areas, you might have to use a surfactant like Tween 20 which will help smooth over those spots.

Not sure if I understand the "discoloration around white areas" of the print. Can you please circle or label these defects? May be still related to the issue described above.

Finally, I suggest that a controlled test for the correct exposure be done without any objects on top so you can get an idea what exactly is going on. If you do not have a step-wedge that was shown by hol571, you can use a simple test-strip method that is used in the darkroom, exposing different times on the same piece of paper to get at what is called "minimum exposure for maximum density." Your exposure time might be in minutes and you might be playing in hours. Too much exposure can also decrease the blue density - above a certain level. Exposure times will also differ depending on the time of the day and whether it is cloudy or clear. So that's an another variable to be kept an eye on.

Niranjan.

 

[Niths]

In brown bottles and away from light and heat, they should last months, if not longer, indefinitely even - as I understand. I only make small quantities that last me 2-3 months at a time so I have not experienced longer times. If you do not have brown or amber bottles, wrap them in aluminum foil or black plastic or something opaque.

Niranjan a quick ques.. What is the usual color of the emulsion after coating on paper.. Is it yellow or green?

 

[nmp]

Niranjan a quick ques.. What is the usual color of the emulsion after coating on paper.. Is it yellow or green?

It should start out as kind of bright yellow - at least the green form of FAC. If it left to stand in the solution form (mix of A and B) for a time, the fresh coating starts taking on greenish tinge - indicating there is some Prussian blue in the sensitizer (blue + yellow = green.) A green coating will have greater propensity for blue staining in the highlights (depending on the wash routine of course.) Also freshly coated and dried paper will turn greener over time - ultimately of course it will turn blue. I can't be sure about the brown form unfortunately since I have had no experience with it. But I suspect it will be similar (particularly if you are replenishing with citric acid as discussed in this thread.)

I see that Amazon India carries the green form of FAC. Why not get some of that and you don't have to wonder whether the any problems you have are related to the brown version or something else.

https://www.amazon.in/Ammonium-Ferr...ferric+ammonium+citrate&qid=1604762271&sr=8-2

:Niranjan.

 

[Niths]

It should start out as kind of bright yellow - at least the green form of FAC. If it left to stand in the solution form (mix of A and B) for a time, the fresh coating starts taking on greenish tinge - indicating there is some Prussian blue in the sensitizer (blue + yellow = green.) A green coating will have greater propensity for blue staining in the highlights (depending on the wash routine of course.) Also freshly coated and dried paper will turn greener over time - ultimately of course it will turn blue. I can't be sure about the brown form unfortunately since I have had no experience with it. But I suspect it will be similar (particularly if you are replenishing with citric acid as discussed in this thread.)

I see that Amazon India carries the green form of FAC. Why not get some of that and you don't have to wonder whether the any problems you have are related to the brown version or something else.

https://www.amazon.in/Ammonium-Ferr...ferric+ammonium+citrate&qid=1604762271&sr=8-2

:Niranjan.

Wooow! Thanks a million for the Amazon link.. It wasn't available when I had checked.. I can't thank you enough. I have placed the order.. I will keep you posted once I get it (hopefully nothing goes wrong with the availability). I can't wait to try it

On your response to the color of the emulsion - yes mine is also yellow and turns green over time.. Thanks much again!

Thanks
Nithya

 

[Niths]

It should start out as kind of bright yellow - at least the green form of FAC. If it left to stand in the solution form (mix of A and B) for a time, the fresh coating starts taking on greenish tinge - indicating there is some Prussian blue in the sensitizer (blue + yellow = green.) A green coating will have greater propensity for blue staining in the highlights (depending on the wash routine of course.) Also freshly coated and dried paper will turn greener over time - ultimately of course it will turn blue. I can't be sure about the brown form unfortunately since I have had no experience with it. But I suspect it will be similar (particularly if you are replenishing with citric acid as discussed in this thread.)

I see that Amazon India carries the green form of FAC. Why not get some of that and you don't have to wonder whether the any problems you have are related to the brown version or something else.

https://www.amazon.in/Ammonium-Ferr...ferric+ammonium+citrate&qid=1604762271&sr=8-2

:Niranjan.

It's sad my order got cancelled

 

[nmp]

It's sad my order got cancelled

That's too bad...am surprised how hard it is to get it in India.

 

[NedL]

sorry I'm late to the party but I'd just like to say some of those are looking really good!

 

[Vandita]

It's sad my order got cancelled

Hi Nithya!

I hope you got your green Ferric Ammonium Citrate (FAC). If not, you can try Ferric Ammonium Citrate (Green, 100 g) India – Tanotis, they import Green FAC and get customs cleared on their own, so you don't have to worry about anything. I am holding back on ordering it because of the expense involved. But apparently if you order more the cost comes down. I am always up for splitting these things (hint hint). I am failing with my current locally procured batch of green FAC. So also trying to work with the brown kind. Just want to affirm Niranjan's hunch to one of your queries:

3. Yellow stains are manifestation of sensitizer (iron) not being completely washed out of the paper. This could be un-reacted FAC and K ferri by themselves or ferric hydroxide formed as a result of reaction between FAC and the chalk buffer (CaCO3) that is most likely used in the paper. The former is easier to wash out, but the latter is much harder, if formed. Citric acid is a good chelating agent for iron - it works better than the acetic acid to carry these iron compounds out of the paper. Try treating the paper with 1% citric acid and see if it clears. If there is any hydroxide, it is much more difficult to clear once dry so it is best to do this while you are doing the wet processing. You can simply replace the vinegar with citric acid in the process. I would start with 0.25% and see how that works and increase if necessary.

I did two tests with brown FAC in the sensitizer, with 260GSM watercolour paper, and 140GSM sketchpad paper, with the same exposure. Observed the following:

Paper 1 turned yellow in the highlights. Probably due to reaction with buffer. My first development bath had 2% vinegar but I will try again with citric acid as suggested. This never happened before with any of the green FAC I've used in the past. The problem with those was blue staining in the highlights. Also if the highlights did clear out, the whites turned gray over a few weeks. I read somewhere that this could be due to chlorination and the final rinse can be 15 minutes in distilled water to prevent that.

Paper 2 was a deep blue with no staining in highlights in the same bath! Contrast was great. Maybe unbuffered. It does say acid-free though.

 

[Vandita]

Here are my unsuccessful attempts at removing yellow stains from highlights using 17% Brown FAC for Solution A. Used Citric Acid 1% for 1st development bath, and then another bath in the same, followed by rinse and hydrogen peroxide soak (made no difference). Followed the same method for vinegar. Contrast is greatly lowered and while I like Citric Acid experiments for photograms, I find it useless for digital negatives, which were working perfectly with my older good Green FAC.

It says in Cyanomicon Appendix III.5 that Brown FAC has "a much greater tendency to leave residues of hydrated ferric oxide in the paper, with consequences both for the colour and the stability of the resulting cyanotypes"

 

[nmp]

Here are my unsuccessful attempts at removing yellow stains from highlights using 17% Brown FAC for Solution A. Used Citric Acid 1% for 1st development bath, and then another bath in the same, followed by rinse and hydrogen peroxide soak (made no difference). Followed the same method for vinegar. Contrast is greatly lowered and while I like Citric Acid experiments for photograms, I find it useless for digital negatives, which were working perfectly with my older good Green FAC.

It says in Cyanomicon Appendix III.5 that Brown FAC has "a much greater tendency to leave residues of hydrated ferric oxide in the paper, with consequences both for the colour and the stability of the resulting cyanotypes"

View attachment 277241

HI, Vandita:

Just judging by the comparisons in your attachments, I wouldn't call this unsuccessful at all. That is a dramatic difference, even on the 2nd digineg-based print. The yellow haze that made the blue turn greenish is by and large gone. If anything, seems to me that there is blue staining the highlights - which tends to increase on acid (either citric or acetic) development. To counter this tendency, my favorite process has been developing in plain tap water first (which should not be alkaline, distilled water if that's so) for 1/2 to 1 minute followed by a couple of citric acid baths. That seems to give me a best combination of cleaner highlights (blue as well as yellow) and a good Dmax.

:Niranjan.