A few questions about "new" cyanotype

I've been having a ball printing kallitypes since I got my ideal tone curve dialed in pretty well for the creation of digital negatives. Long story short, decided to try cyanotypes as well.

In the research phase, I found Mike Ware's article where he does a good job selling the advantages of his new cyanotype process over the traditional one. I have ordered the chemistry needed to make up his sensitizer recipe. I'm all set on everything else (contact printing frame, digital negatives that should be in the right ballpark for density/contrast range, UV light, and Hahnemuhle Platinum Rag so I don't have to worry about any of the paper-related woes people tend to run into).

His article mentions that hard tap water with high calcium content is going to hurt the image. That pretty much describes my water to a tee. Comes out of the tap at pH 8.1, very high in calcium, and probably has other stuff (iron, copper, etc.) to boot since it's out of a well. I was aware that this would be a problem for Kallitypes, so I keep a jug of slightly acidified tap water on hand at all times. I just add about 1/8 of a tsp of citric acid to a gallon of tap water, and the pH goes down to around 6.5. For Kallitypes, I can safely use this for my back-to-back, 1-minute rinses immediately after developing, and it doesn't cause any staining or other problems. Will this acidified tap water work without compromise for new cyanotypes? Is there an advantage to making something even more acidic? I know traditional cyanotype tutorials often recommend developing in vinegar/water mixes or even straight vinegar. Do I need to worry that simply acidifying my tap water does not solve the problem caused by the presence of calcium?

Final question is, yea or nay to hydrogen peroxide? My understanding is that it simply makes the process of oxidation go much faster, so I can see the final color and tone of the print after a few minutes instead of a few days. Anything I'm missing there? If that's the case, I'm going to use it, at least during my initial testing phase to get the process worked out and leading to a good result.

BHuij said:

Will this acidified tap water work without compromise for new cyanotypes?

Click to expand...

Sure!

BHuij said:

Is there an advantage to making something even more acidic?

Click to expand...

I don't think so. New Cyanotype is less liable to have the blue image washing out than Classic Cyanotype, so acidifying the water a little more probably won't hurt. But it likely won't help either. Just give it a try with the mix you're presently using; if you have any trouble with unreacted salts washing out and the whites clearing, you can always acidify the wash a bit more.
It's been a while since I did any New Cyanotypes, but I don't recall the rinse water as a particularly critical parameter, other than that it helps if it's slightly acidic.

Btw, your tap water sounds pretty normal to me.

BHuij said:

Do I need to worry that simply acidifying my tap water does not solve the problem caused by the presence of calcium?

Click to expand...

Nah. Calcium is probably present in significant amounts in 99.9998% of the tap water across the globe. It won't hurt in New Cyanotype. Just ensure the pH remains a little below neutral.

BHuij said:

Final question is, yea or nay to hydrogen peroxide?

Click to expand...

Whatever floats your boat Some say that peroxide-treated prints end up having slightly less dmax than air-oxidized ones. I never tested systematically for it, but I wouldn't be surprised if 'they' are right. I've got a hunch they may be. Does it really matter much? I wouldn't say so. I'd recommend trying it out with two identical prints/ test strips and evaluating the results after a couple of days.

Here are the results of my experiments on using vinegar in washes with classic cyanotype, https://www.photrio.com/forum/threa...the-washing-of-traditional-cyanotypes.177366/

There are probably no differences between the classic and the new process in this regard. The issue is alkaline hydrolysis of Prussian Blue after the image is formed so the pre exposure chemistry should not matter.

fgorga said:

There are probably no differences between the classic and the new process in this regard.

Click to expand...

I'd be very cautious with this statement. One of the advantages that Mike Ware attributes to the New Cyanotype process is far less loss of density during rinsing. See here: https://www.mikeware.co.uk/mikeware/New_Cyanotype_Process.html
Note in particular drawback no. 4 to the classic cyanotype process and how New Cyanotype apparently overcomes this.

As a result, as a non-chemist, I'm a bit wary of attempting to equate observations of Classic cyanotype processing to New Cyanotype.

BHuij said:

Will this acidified tap water work without compromise for new cyanotypes? Is there an advantage to making something even more acidic?

Click to expand...

Classic cyanotype is much more sensitive to highlight staining from too acidic clearing baths. With New cyanotype you should not have any problems (leaving it out is probably worse).

I would recommend trying 1% citric acid in the first bath, and using your mix of 1/8 tsp per gallon in the rest. You can finish with a minute or two in pure tap water if you want to wash out most of the acid.

And you can adjust the concentration of H4Citr in the first bath: If you see staining in the highlights - lower it. If you have weak Dmax - raise it.

The results will vary with different papers / sizings. A hard sized paper can easily catch the prussian blue in the water and stain the highlights.

BHuij said:

Final question is, yea or nay to hydrogen peroxide?

Click to expand...

H2O2 is useful if you want to tone the print before drying it. It can bleach the print a little though.

I dabbled with the new cyanotype, and ended up going back to the original formula. I found it finicky.

I read through that thread where Mike Ware weighed in, and found it illuminating. Seems that various types of acid can really help increase dmax by enabling the formation of more Prussian Blue than would otherwise occur. At least that's my non-chemist understanding of what's going on. The flip side is that acid can cause some of the other compounds in the emulsion to move around on the surface of the print and possible end up staining the highlights. If indeed the New Cyanotype process is less prone to this highlight staining problem, then maybe I have a new use case for the 3% citric acid I keep on hand as a kallitype clearing bath. Possibly more aggressive than strictly necessary, but citric acid is cheap, and it saves me the trouble of storing yet another jug of something that only has one purpose.

I think I'll test out the regular slightly acidified tap water as well as the kallitype clearing bath and see if one yields a significantly better print (esp. in terms of Dmax). Interestingly there also seems to be some relatively significant differences in tone that can result from different types of acid (citric vs acetic vs nitric or others). I know Mike Ware recommends nitric acid for his process. I have citric and acetic so I'll probably experiment with those first.

At any rate, thanks all for your insight. I think I'm at the point I seem to get to a lot where I'm waiting on stuff to ship before I can actually do anything, so I tie myself in knots over-researching it. I'll try to just chill out until my ammonium dichromate and ferric ammonium oxalate get here

Chemicals got here today and I got everything mixed up. I followed Mike Ware's instructions to a tee, down to the exact solution temperatures for mixing. He said after a couple of hours for crystals to form in the sensitizer that I should expect around 62ml of liquid (leftover after straining out the crystals). I got about 40ml. Still mixed up to 100ml total. I'll give it a few days and see how it prints.

Reporting back here for posterity. I'm starting by just kind of throwing things at the wall to see what sticks.

Test 1: Used 12 drops of sensitizer on a 4x5 sheet of HPR. It seems too much sensitizer, I think. No Tween 20, no citric acid. Dried for one hour in darkness. Honestly the sensitizer already looked very slightly fogged after that. Possible some UV light snuck in through the window of my office; I had the bathroom darkroom door open for part of the sensitizer application. Sloppy. I used a digital negative with no contrast curve applied (i.e., it would probably print well on grade 2 silver gelatin paper). Did a test strip in 1-minute increments of exposure from 0 to 7 minutes to see if I could find the minimum exposure to get close to dmax through the Pictorico base. First bath was in 3% citric acid solution for one minute. Notable loss of density in the print. Two subsequent baths of 10 minutes each in slightly acidified tap water. More significant loss of density. During the last minute of the last rinse, I added a capful of hydrogen peroxide to the small, 5x7 tray. I can't tell if it did anything, certainly I didn't see a sudden and dramatic change. My Dmax is less than impressive at this point; everything looks pretty faded. Print is drying now. I'm also pretty sure I can see slight fogging in areas of the print that got zero exposure in the light box. I'll know more when it's totally dry and I can inspect under better light.

Test 2: Sensitized at the same time as test 1 with the exact same method. Also possibly a little fogged. This one went in a paper safe while Test 1 was being exposed. I used a digital negative with my calibrated curve that works well for kallitypes (significantly more contrast than an uncorrected digital neg). Exposed for 4 minutes in the light box. Same development procedure as test 1, except no hydrogen peroxide. Still getting pretty significant loss of density, particularly in the shadows, during the initial and subsequent clearing/rinsing baths. Maybe not as bad as the first test though. Hard to say if exposure is halfway decent, because I've lost so much print density and contrast from the wet processing that the images aren't particularly inspiring. There's definitely blue in the water that's rinsing down the sink.

Test 3: Used 8 drops of sensitizer on a 4x5 sheet of HPR, as well as 1 drop of 20% Tween 20 solution, and 1 drop of 10% citric acid solution. Did not let UV light into the room during sensitizing this time. This total of 12 drops seems kinda dry, probably not quite enough. Likely because the sensitizer is absorbing into the paper a lot better with the addition of the Tween 20. Somewhere in here I'll find a sweet spot, but it's looking like I'll need more sensitizer total volume per print for new cyanotypes than for kallitypes. I'll expose this one for 8 minutes with the same negative as test 2 (should be overkill on exposure), and see if I'm still losing all my density during processing.

At this point I have a few theories to test about why my final results are showing a pretty bad dmax and overall density:

1. Dmax is fine, I just need to wait for dry down and a day or two for total oxidation (one can hope)
2. I used too much sensitizer and didn't let it dry properly before exposure (although this seems like it would increase dmax rather than decreasing it?)
3. Without Tween 20, the HPR was not absorbing the sensitizer well, so it was just sitting on the surface and easily washed off (this seems likely)
4. My sensitizer is weak. I only got ~2/3 of the liquid volume I was supposed to, per Mike Ware's instructions on making the sensitizer, so I should have added distilled water to a total volume of ~67ml instead of 100ml. Hope it's not this, but it likely is, at least to some extent. Luckily this stuff is cheap, so making up a new batch only really costs me time.
5. I'm using too much acid? I've heard of people developing in undiluted vinegar (which should be ~5% acetic acid), so I don't think 3% citric acid should be hurting anything.
6. Any other suggestions welcome. I'll report back as I learn more.

Test 3: 8 drops was definitely not enough sensitizer, now that it's soaking into the paper better, I got pretty incomplete coverage of the 4x5 paper. That said, it is showing a FAR better dmax than the first two, and processing is having much less effect on that dmax. Still a bit of blue washing down the sink after the first clearing bath. So I think the first two tests were simply washing off the surface of the paper because they didn't get absorbed into the fibers effectively. Contrast seems too high in this print. The shadows are predictably a bit blocked up because of the long exposure, but there are highlight areas that are paper base white still. It seems I need a less contrasty negative for this process than for kallitypes, at least with the sensitizer how I'm mixing it now. Mike Ware suggests that adding more citric acid to the sensitizer can decrease image contrast somewhat, so I'm going to give that a shot. If I can find a ratio of sensitizer to citric acid to Tween that lets me achieve a good print using the same negatives as I do for Kallitype, it's going to save me a lot of time, ink, and Pictorico in the long run.

Test 4: 12 drops of sensitizer on a 4x5 sheet, with 2 drops each of 20% Tween 20 and 10% citric acid. This feels like about the right amount, the time it took to brush on and dry, and how easy it was to get an even coat were basically the same as my kallitype printing. Now that I think about it, I've had my wires crossed on the math for this until now. I use 6 drops EACH of two different sensitizer components for Kallitype printing, so 12 drops total (plus the Tween). for a 4x5 print. Meaning liquid volume is probably roughly the same between kallitype and new cyanotype. When this sensitizer is dry, I'll try printing an uncorrected negative on it with a 6 minute exposure. If that comes out without enough contrast in the print, then I've established upper and lower bounds for negative contrast that works with this ratio of sensitizer components.

I think most of your theories sound reasonable (1-5).

1: Most of the density *should* appear instantly when H2O2 is added.

2: Some (print-out) processes like damp paper. But with cyanotype results seem best if the print gets completely dry at some point between coating and exposing. If not, there can be more wash off.

3: Using the right amount of surfactant can make a big difference. You want the sensitizer to absorb into the paper, but not too deep either. The amount you used in test 3 sounds reasonable to me.

You can also pre-humidify the paper by holding it above a sink with hot tap water for a minute. That can help a lot.

4. Some dilute their sensitizer when they have problems with coating marks, at the cost of lower Dmax and contrast. You should still be able to make good prints. You could double coat, but that's asking for other problems IME.

5. I don't know. I think it *should* work. They say new cyanotype loves acid.

Good luck!

Edit: You beat me with your new results. Sounds like you are getting there.

1. I added some peroxide to test 3 and it did noticeably deepen the blue color and dmax this time. I suspect in my first test there wasn't enough chemistry left on the paper by the time H202 got introduced.
2. Good to know. I live in a desert and the last thing I wanted to do was try and humidity control my darkroom. I managed to find a process that works without manipulating any of that for kallitypes, I ought to be able to do the same for new cyanotype. I'll make sure things are bone dry before putting them in the contact printing frame going forward
3. Yep, this is a variable I'll make sure to get dialed in.
4. My coating marks were really just a case of dry brushing because there wasn't enough sensitizer. I expect Test 4 will solve that problem.
5. Yeah this doesn't seem to be the issue, acid doesn't seem to be affecting image tone negatively since I added Tween.

If I'm getting these results with sensitizer that is less concentrated than Mike Ware recommends, there's part of me that wants to just bite the bullet on making up a new batch at the right concentration before I waste time trying to fine tune ratios for image contrast. That said, more dilute sensitizer should equate to lower contrast, and I may need that to make my kallitype negs work.

Test 4: 6 minutes is slightly too long of an exposure, I think. Came out closer to correct print contrast using the uncorrected negative than the kallitype-corrected negative, unfortunately. I do think I want slightly more contrast than I'm getting from this negative, and specifically my shadows muddied up pretty quickly (same thing that happens when I print kallitypes without adding a lot of contrast to the shadows). So the name of the game is trying to reduce the contrast chemically by varying the sensitizer:citric acid:tween ratio. Test 4 was 12:2:2 and had too much contrast (or would have, with the kallitype-corrected negative). From now on, all tests will be using the corrected negative.

Test 5: 10:4:1 ratio. Brush was a bit dry, and I expect dmax to suffer a little bit as a result. I need to be pre-wetting my brush like I do for kallitypes, to prevent it from soaking up all the sensitizer before it can spread around the paper. This will be exposed for 5 minutes.

An additional source to consult is Sam Wang, who has been pushing the envelope in the “new cyanotype” world.

Good to know - I'll give him a Google when I've stepped back from taking my own swing at it here.

Test 5: It appears the citric acid did indeed help lower the contrast a bit, it came out reasonably good with a kallitype-tuned neg. Noticeably better than Test 3 using the same negative. 5 minutes is still too long of an exposure, but not by much. I might be running up against the limits of what I can learn from printing this same test negative over and over. Ready to try a larger, "real" print.

Update for Test 5: I accidentally let this sit in the final rinse bath - stagnant water of pH ~6.5 - for a little over an hour, and lost a huge amount of density. Seems like there's no real limit to being able to accidentally wash out more of the image than I intended. I'll have to remember to be strict about my wash times to make sure they don't go too long.

Test 6: Using the 10:4:1 ratio, stepping up from ~4x5 print size to a negative I have that's 6.8x8.5". That's more or less 3x the area, so I went with 30:12:3. Application onto an 8x10 sheet went well. I'm going to try exposing this one for 4 minutes. That might be a little bit too short, but I'd rather err on that side for this particular photo.

I use the traditional cyanotype. You can also use tween20 with that if needed. I'm not a chemist and people tell me the dichromate in New Cyanotype can be safely neutralized, but I don't have the chemistry knowledge to be personally assured of that. (I use a well and septic system rather than a public treatment system)

Test 6: 4 minutes seems to be the ticket, and this ratio of sensitizer seems to be giving me a tonal range pretty comparable to what I'm getting printing a kallitype from the same negative. I'll know more for sure when this print is fully dry and can be inspected under daylight conditions.

Edit: I spoke too soon. I lost so much density by the time it was done rinsing, so while tonal range seems smooth and I'm not blocking up or losing detail at the ends of the scale, I'm just getting light-colored prints that don't have a punchy dmax.

One thing odd about this one is that it seemed like it was fogging pretty badly. After applying the sensitizer, I let this one sit in the dark for 2.5 hours. All the others dried for one hour and didn't seem to fog at all. This one looked really fogged (very much turning greenish instead of yellow), but I decided to expose it anyway. My lighting in the darkroom for alt processes is a single yellow bug light, so it's really hard to assess whether I got good clearing while I'm in there. That said, the print is in the rinse right now and the highlights seem perfectly white, not fogged at all. Guess I'll know more, once again, when it's dry.

Things are dry enough that I know I'm not getting the dmax I expect. I have a cyanotype I received from a print exchange that has a really nice, deep blue. I believe it's a traditional cyanotype, and the new cyanotype should be theoretically possible of at least that much depth, if not more. On the bright side, my highlights cleared to paper base white no problem on Test 6, despite the paper looking pretty fogged pre-exposure.

I'm going to run one more test tonight and purposely overexpose by a lot just to confirm that I'm not simply failing to give it enough light.

At this point I believe it's at least one of the following factors:

1. Severe underexposure (with additional contrast needed if additional exposure actually does yield a proper dmax)
2. Paper not absorbing sensitizer enough, still. Extended rinses are killing my density a lot more than I feel like they should be. I guess more Tween 20 if that's the case, but I'm already using about 150% of the Tween I use for kallitypes, and the same paper. Not sure why cyanotype chemistry would need so much more, especially in the dry climate I live in
3. Sensitizer is too dilute. I expect this is probably the biggest issue, so I'm going to make up another batch tonight and make sure it ends up at the correct concentration.
4. My rinse water might not be as acidic as I thought. Tomorrow I'll actually measure the pH to confirm it's at 6.5 like I thought, but alkaline rinse water could explain why my density seems to evaporate after 20 minutes in the tray.

Test 7: 10:4:1 ratio again, 30/12/3 drops of sensitizer, 10% citric acid, and 20% Tween 20 again (same as Test 6). Just over an hour dry time. 16 minute overkill exposure in the light box.

Apologies to those of you who have been getting email notifications every time I update my long-winded lab notes. I'm pretending someone will stumble on this thread from Google search results in 8 years and be really glad it's here. I think this is the last entry for the day.

Test 7's 16-minute exposure gave me... a really, really nice dmax. One that changed very little after 1 minute of clearing and 20 minutes of rinsing, and got even deeper with a bit of H202 during the last 5 minutes in the tray. The excessive exposure time also completely crushed my shadows to nothing, made my midtones into shadows, and made all but the very densest highlights on the negative into midtones. I'm actually shocked there was anywhere on the negative that managed to keep paper base white when everything else was so obviously overexposed. Don't underestimate that Pictorico, I guess.

This is kind of frustrating, because it seems to indicate that getting my existing kallitype digital negs to yield a good tonal range, good shadow separation, highlight detail, and a good dmax all at the same time with the new cyanotype process is more than simply a matter of chemically altering overall contrast in the print. It seems like I will probably just need a different tone curve altogether for optimal digital negs to print excellent new cyanotypes. I was really hoping I could double up on these things.

I still think it's worth trying sensitizer that's at the correct dilution per Mike Ware's instructions. As a non-chemist who is totally unqualified to theorize about these things, I wonder (or maybe just hope) that a more concentrated sensitizer will require less light to achieve a proper dmax, one dark enough that it doesn't wash out, and therefore I'll be able to attain it without crushing the rest of my tones using a shorter exposure. I have a beaker of ferric ammonium oxalate, ammonium dichromate, and potassium ferricyanide chilling in the closet growing crystals right now. Once again followed the instructions to a tee, but whatever volume of liquid I end up with, I'll adjust the final balance of distilled water to get a concentration that matches Mr. Ware's 62ml to 100ml ratio.

I got lucky and worked from home today, so I could hop in and out of the darkroom all day and get a lot of testing done. That won't happen again until later next week, but I'm hoping to still be doing at least one or two prints per evening until I figure this out, (or get frustrated enough to table the project for awhile). With a little luck, tomorrow I'll be able to at least get a general idea of how much of a difference the more concentrated sensitizer makes.

I also think I'll do some scans. I'd love if people more experienced with the process could take a look at my results so far and offer suggestions.

I got my ducks in a row to track my results better internally without notifying everyone. I'll share notable results here, which hopefully means my next post will be to showcase some success. Instead of going with raw ratios of drops, I've set up a spreadsheet where I can enter the desired liquid per square inch of image area, as well as the required concentration of citric acid and Tween 20 in that liquid, since Mike Ware has recommendations for these concentrations. Now I can just plug in the target volume and concentrations, and it will give me "number of drops" for each of the three component solutions for any given print size.

All my tests so far have been pretty slapdash, in a "throw things at the wall and see what sticks" kind of methodology, and I think I'll benefit from working a bit more scientifically going forward instead of trying to juggle multiple variables around at once.

Tests 8 and 9 will be simple test strips to determine minimum exposure time to dmax through film base using the new sensitizer which is at proper dilution.

Test 10 will be using the properly determined print time, with Mike Ware's recommended baseline 2% citric acid and 0.5% Tween 20 concentrations, at 0.03ml of total liquid per in^2 of image area. Depending on those results, I may decide to go a bit wetter or a bit drier on liquid per sq. in, or scoot citric acid concentration up/down as contrast control. I'm also curious to see whether an array of Tween 20 concentration tests would show an appreciable effect on dmax, or yield a "sweet spot" for the right amount of absorption, given my environmental factors.

If a round of contrast testing can't give me a print with good tonal range, dmax, and shadow separation at the same time, I'll consider that to be definitive proof that my kallitype tone curve does not work for this process, and start playing with new curves accordingly. Fingers crossed that it doesn't come to that

Once I started working in terms of actual concentrations, and did a proper film base test strip, things fell mostly into place a lot quicker than I expected. This print isn't perfect, but it's definitely the best I've gotten. Dmax is good, shadow separation is about 99% as good as my kallitypes from the same negative. For the first time, I had highlight staining from pigment washing off during the first clearing/rinsing bath (visible along the top and right edges). This suggests I may not be getting the sensitizer into the paper fibers as effectively as I want to. Makes sense; Mike Ware's recommended 0.1% to 0.5% Tween 20 content is less than I was using for any of my earlier tests (which had no highlight staining).

Interestingly, this is a 10.5 minute exposure. The same negative gives an ideal kallitype in 4 minutes of exposure. Documentation for new cyanotype says in an "average UV exposure unit," exposures should be between 2 and 4 minutes. I guess that's kind of a meaningless metric, other than mine appears to put out less light than Mike Ware considers "average" My test strips gave noticeable increases in dmax with every extra minute of exposure up until I hit about 10-12 minutes.

So a bit of fine-tuning to do on Tween 20 concentration, and perhaps ever so slight changes in citric acid concentration. But I'm quite happy with how this came out, and ready to do some more printing! FWIW, the magic numbers for me so far are 0.032ml of total liquid per square inch of image area, with ~0.5% Tween 20 concentration (achieved by adding drops of 20% Tween 20 to the sensitizer immediately prior to application), ~2% citric acid concentration (achieved by adding drops of 10% citric acid to the sensitizer immediately prior to application), and the balance actual sensitizer, and I suppose also distilled water from the non-sensitizer solutions being mixed in. I calculate the ml amounts exactly, and then convert to whole number "drops" assuming 1 drop = 0.05ml. I also never let the Tween 20 fall to zero drops, even if smaller print sizes suggest something like 0.27 drops. It seems critical for my success with this process to have enough Tween, and the effects of too much Tween (within reason) don't seem to be anything noticeable.

For this print, that ended up being 23 drops of sensitizer, 6 drops of 10% citric acid, and 1 drop of 20% Tween 20. I expect doubling the Tween would probably prevent highlight staining.

BHuij said:

For this print, that ended up being 23 drops of sensitizer, 6 drops of 10% citric acid, and 1 drop of 20% Tween 20. I expect doubling the Tween would probably prevent highlight staining.

View attachment 330077

Click to expand...

That is a nice print. This is not how I would have approached it (that's why I don't have a print to share....) but I am glad it all worked out in the end. Tween can be a two-edged sword - too much of it and the sensitizer goes too far down the paper and you lose the Dmax as a result.

:Niranjan.

nmp said:

That is a nice print. This is not how I would have approached it (that's why I don't have a print to share....) but I am glad it all worked out in the end. Tween can be a two-edged sword - too much of it and the sensitizer goes too far down the paper and you lose the Dmax as a result.

:Niranjan.

Click to expand...

Yeah, I’m guessing there’s a sweet spot in there somewhere, but honestly even when I have clearly not added quite enough, I’m pretty happy with this dmax. So I will probably just creep up on the right amount to stop the highlight staining and call it good there.

BHuij said:

Click to expand...

I think your print looks very good. Great to see it's all working for you!