Kallitype Woes

[BHuij]

Hey everyone--

TL;DR version: I can't even get a test strip for finding optimal UV exposure time through film base to work properly, and I have exhausted all of the troubleshooting avenues I could think of.

I am trying to “graduate” from salt prints to kallitypes. I’ve gotten good results with salt prints on a Strathmore hot press watercolor paper, using Fixxons film. This is with a home built UV exposure box, which is a bunch of UV LED strip lights about 6” or so above the contact printing frame. With that setup, I reach dmax for my salt prints through the film in 12 minutes of exposure time. When I did the tests to find that time, the strip was very clearly demarcated at all the sections of different exposure

For kallitypes, I decided to just shell out for Hahnemuhle Platinum Rag and Pictorico transparency film since it’s supposed to be a tried-and-true combo.

I am following Sandy King’s instructions and chemistry recipes to a tee, using the #1 gold toner (the one without thiourea, just gold chloride, citric acid, and distilled water). I am working under a 40W equivalent LED yellow bug light. My tap water is slightly alkaline, so I’m using distilled for all solutions, and a gallon jug of tap water mixed with enough citric acid to reach a pH of 6.5 for rinsing.

My first few tests were with 20% ferric oxalate I got from The Photographers Formulary. I ordered a bottle of dry ferric oxalate intending to mix my own since it doesn't keep well in solution, and I'm a low-volume printer. Before shipping it, they reached out to me to say they were discontinuing the dry product and the only stuff they had on hand was ~20 years old. They kindly offered to substitute in an equivalent amount of already mixed 20% solution, and toss in the dry stuff for free.

The ferric oxalate solution they sent was fairly green and a little cloudy. When mixed with the 10% silver nitrate in a shot glass, the solution looked slightly grayish and not very transparent before even coating the paper. I coated the paper with a glass puddle pusher (same as I have been using successfully for salt printing). The first test was almost immediately fogged and basically turned very dark as soon as I tried to do a “test strip” to find the right exposure time, even without developing. I also couldn’t see much by way of separation between the differently exposed areas. 20 minutes of UV light was about the same darkness pre- and post- development as 2 minutes of UV light. Not wanting to waste toner, I just chucked the test strip after rinsing. The entire thing was a pretty homogeneous muddy brown.

Suspecting my bug light first, I did my next test with only red safe lights that I use regularly for silver gelatin printing. Same result, basically complete failure. Some research led me to believe it was probably bad ferric oxalate solution (old or otherwise containing unacceptable amounts of ferrous oxalate, oxalic acid, or both). I mixed up my own 20% solution with hot distilled water and the dry stuff from TFP. The dry stuff was in the form of fairly large, very bright fluorescent green crystals. Not a great sign. Sure enough, it never really fully went into solution for more than a couple of minutes at a time. Always had crystals precipitating out. I never bothered trying a test strip with this.

Went ahead and ordered some powdered ferric oxalate from Bostick and Sullivan. It showed up as a very fine powder that was dull greenish yellow in color. Seemed much better. I mixed up a 20% solution in a new brown glass dropper bottle using boiling hot distilled water, per enclosed B&S instructions. It went into solution great, and 12 hours later I tried another test strip.

Coated the paper under yellow bug light and let it dry for 30 minutes in darkness. Totally dry to the touch. No fogging, which was encouraging.

Tested 2 minute exposure intervals from 2 minutes through 20 minutes in the UV box. Prior to development there was a pretty clear gradient visible on the paper. Darker tones than I expected for undeveloped kallitype, but I proceeded anyway. Unfortunately, once developed in sodium citrate, this demarcation went away and basically the entire sheet is a mottled dark brown again. This time I followed through the entire process of rinsing, clearing, toning, fixing, hypo, 30 minute wash, and drying to see if the test strip improved. It did not. The finished dry product is pretty much homogeneous, with a fairly neutral, slightly bluish dark gray covering the entire paper and almost no visible differences between differently exposed areas.

Not sure where to troubleshoot next. Suggestions welcome. I’ve seen some really beautiful kallitypes and would love to be able to successfully make my own. Help a newbie out?

 

[Andrew O'Neill]

Your ferric oxalate solution sounds suspect. Have you tried mixing the powdered stuff yet? I prefer to get powdered ferric oxalate from Bostick and Sullivan.

 

[BHuij]

Your ferric oxalate solution sounds suspect. Have you tried mixing the powdered stuff yet? I prefer to get powdered ferric oxalate from Bostick and Sullivan.

Most recent test was with freshly mixed powdered ferric oxalate from B&S. It seems like good stuff, but I can’t yet rule it out as part of the problem.

 

[koraks]

Prior to development there was a pretty clear gradient visible on the paper. Darker tones than I expected for undeveloped kallitype, but I proceeded anyway. Unfortunately, once developed in sodium citrate, this demarcation went away and basically the entire sheet is a mottled dark brown again.

Something's amiss with your developer, I'd say. Can you tell a bit more about the sodium citrate; where you got it or how you made it, and to what extent you're certain it is what you think it is?
Also, have you tried different papers yet?

 

[BHuij]

Something's amiss with your developer, I'd say. Can you tell a bit more about the sodium citrate; where you got it or how you made it, and to what extent you're certain it is what you think it is?
Also, have you tried different papers yet?

Just regular old sodium citrate powder from TFP. Per Sandy King’s instructions, I weighed out 200 grams into a bottle, mixed with 750 ml of distilled water until dissolved, then added water to hit 1 liter. I have two bottles of developer. One is labeled “fresh” and one is “working.” The working one gets used to develop prints. It’s replenished from the fresh one at a rate of 1ml for every square inch of print area developed. Which so far is a total of two test strips, each with about 23 in^2 of area.

I have no specific reason to believe the white powder in the bottle is anything but sodium citrate. Is there some test I can do easily at home that would tell me whether it is or isn’t?

I have not yet tried other papers. Arches Platine and Bergger COT 320 are what I would probably use if HPR can’t get me good results.

 

[nmp]

When you say the final strip is "fairly neutral, slightly bluish dark gray," do you mean like a full blown Dmax or is it more like a mid-tone? I am thinking perhaps your min exp for max density is the vicinity of 2 mins or below (that would be super fast indeed, so perhaps not but it'd be good to eliminate that possibility.) What I do for a totally new process is start from really low exposure like 15 seconds and do 1 f-stop intervals: expose steps of 15s, 15s, 30s, 1m, 2m, 4m, 8m, 16m. This will give you a test strip from 15s to 32m - 8 shots (and 8 f-stops) all together. I also keep the first step unexposed so I get an idea of what the chemical fog is if any. Once I get the exposure time within a stop, then I can fine tune with smaller steps to get the exact time.

:Niranjan.

 

[BHuij]

When you say the final strip is "fairly neutral, slightly bluish dark gray," do you mean like a full blown Dmax or is it more like a mid-tone? I am thinking perhaps your min exp for max density is the vicinity of 2 mins or below (that would be super fast indeed, so perhaps not but it'd be good to eliminate that possibility.) What I do for a totally new process is start from really low exposure like 15 seconds and do 1 f-stop intervals: expose steps of 15s, 15s, 30s, 1m, 2m, 4m, 8m, 16m. This will give you a test strip from 15s to 32m - 8 shots (and 8 f-stops) all together. I also keep the first step unexposed so I get an idea of what the chemical fog is if any. Once I get the exposure time within a stop, then I can fine tune with smaller steps to get the exact time.

:Niranjan.

Good call. It seems like it’s basically at Dmax on the whole sheet. I hadn’t considered that maybe even 2 minutes was too long, since salt prints took so much longer than that. I’ll try another strip with much shorter times.

 

[nmp]

Good call. It seems like it’s basically at Dmax on the whole sheet. I hadn’t considered that maybe even 2 minutes was too long, since salt prints took so much longer than that. I’ll try another strip with much shorter times.

My guess is that the exposure times would be shorter here than salt prints (with the benefit of FO in the mix.) I don't know how much as a rule as I have only done salt.

Also, one thing I have learned is not to give much credence to the latent image as things change significantly when processing is done. What seemed different end up being the same and at other times, what seemed same end up different.

:Niranjan.

 

[koraks]

I hadn’t considered that maybe even 2 minutes was too long, since salt prints took so much longer than that.

Salt prints are very slow indeed; processes like kallitype and Van Dyke brown are much faster. E.g. salt prints take around 11 minutes in my setup to hit dmax through clear film, whereas Van Dyke requires something like 2m20s or so.
It's very well possible that your 2 minute exposure already hits dmax as @nmp pointed out. Sorry I missed this obvious possibility. Forget about the chemistry for now and do as nmp says, and make some test strips with shorter times.

 

[BHuij]

Good call. Thanks all. Is there a point at which my exposure time is too short to be considered reliable or stable? E.g., for silver gelatin I try not to go under 10 seconds, even if it means adding neutral density to extend the exposure time.

 

[koraks]

Is there a point at which my exposure time is too short to be considered reliable or stable?

That depends a lot on the light source, mostly. For instance, with my UV LED light source that has a timer, I wouldn't be concerned going as low as 1 second if the application asked for it, since I know those times would still be more than sufficiently repeatable. With my bank of UV tubes with their inherent startup behavior (they take about a second to come on), I try to not go below 20 seconds.
Btw, I have *never* witnessed the need to go lower than 20 seconds in any UV-sensitive imaging process I've worked with so far. Given that my exposure time for a salt print is in the same ballpark as yours, I wouldn't be too concerned for now with this issue.
Cross that bridge when and particularly IF you ever get to it.

 

[Andrew O'Neill]

My kallitypes take 15 minutes to expose using my BLB unit. 25 minutes for cyanotypes. Kallitypes are seven minutes if I use my 1000W plate burner...but I hate using that thing as it generates too much heat...

 

[DMJ]

I use a UV light that is about 8" from the paper and it takes around 4 minutes for kallitypes. My cyanotypes take much longer, over 10 minutes.

 

[Andrew O'Neill]

One of these days, I'm going to grab some of those UV LED strips and make a unit that exposes much faster...

 

[koraks]

Forget about the strips; get a powerful COB led, suitable power supply and cooler instead.
Or just get one of those high-powered UV floodlights. They're something like $60 or so these days - all you need to do is hook them up to a timer and you're ready to go.

 

[BHuij]

I paid $21 for 40’ of UV LEDs and just did the math to pack them at maximum density onto a piece of plywood. Then added some legs to the plywood and voila. To be honest I was worried it would be under powered, but so far it has worked great for salt prints. Hopefully tonight I’ll have a better result with a kallitype test strip as well, using significantly shorter times.

I also ordered some tween 20. Haven’t been using it and it seems like it was unnecessary for the salt printing paper and procedure I was using, but the sensitizer on my failed test strips so far doesn’t seem to be going on as evenly. Hopefully this helps with that.

 

[BHuij]

After a couple more sheets and a first test print using an actual negative, I have an update.

I did another test strip in 30 second intervals. It gets difficult to differentiate between tones at about 3 minutes and 30 seconds, although I felt that max dmax had been reached closer to 5 or 6 minutes. To see what kind of tonal range I had to work with, I printed a totally uncorrected negative (no curve applied) on Pictorico and printed it at 6 minutes. The attached picture is before it was dry, and it did dry down a bit.



Takeaways from this first attempt:

• I got an acceptably good image! Took me 6 iterations to reach this point when I started with salt printing. Guess skipping all the "maybe this paper will work okay" steps and going straight to HPR was the right move.
• Speaking of HPR, I'm impressed with this stuff. It looks and feels phenomenal. Went ahead and ordered a box of it from B&H, since the tiny sample pack I have is going to run out quick.
• I like the color I get from my gold toner, and I'm glad I don't have any immediate need to experiement with anything else on that front.
  
• It appears I'm roughly a stop shy of paper base white at maximum ink density. I also have shadows blocking up quite a ways before I hit fully transparent. Those things together indicate to me that I can probably get away with less exposure. When I get a chance, I'll try the same negative but expose it for 3 mins and 30 seconds to see if I can still get a proper dmax, while preserving paper base white in the highlights. If not, then I need to find a way to add more contrast. I may experiment with double coating the emulsion, or bite the bullet and introduce a little potassium dichromate into my sodium citrate developer. I was comfortable using chemistry that's pretty benign to the point, but I guess you're not a REAL alt process aficionado until you're screwing around with substances that will straight up kill you if you're not careful.
  
• The step wedge in the image shows pretty clearly that I'm blocking up my shadows early. If shortening the exposure doesn't fix this all the way, it should be simple enough to tweak the curve.
• There's something awesome about being able to use a wet printing process and get a good image from a digital capture. Feels like the whole wide world of printing has opened up now since I have a big portfolio of d-word images in addition to my physical negatives.
• Having now tried several coatings with a puddle pusher and getting uneven results, I decided to use a brush for this. Went on easy and looks way better. Interesting, considering I went from a brush to a puddle pusher for the exact same reason with salt prints, and get better results with the puddle pusher there. I am using Tween 20 here and didn't use it for salt printing, so maybe that's the difference.

Thanks all for your help. I'm encouraged by what I'm seeing and excited to get this all dialed in the rest of the way so I can start making some larger prints for display.

 

[Andrew O'Neill]

Regardless of process, the first thing I do is a min time/max black test strip. No image. Just film base material. As far as using a surfactant such as Tween 20, I always do. I don't have any Tween 20, so I use a drop of Photo-Flo... and I only do this if my workroom RH is dry.

 

[koraks]

That looks pretty darn good!

It appears I'm roughly a stop shy of paper base white at maximum ink density. I also have shadows blocking up quite a ways before I hit fully transparent.

Such are the woes of digital negatives
Maybe reducing exposure will help, but frankly I don't think you're ever going to be able to use the full tone scale of the printing process with this inkjet printer. I recognize your findings (albeit not necessarily with kallitypes, but other processes). These are twofold: (1) dmax of the inkjet negative is generally insufficient to create pure paper white and still get dmax. (2) you need to apply a *very* steep curve shape in the shadows of the print (clear/light zone of the negative) to get good shadow separation.
Issue #1 is just what it is. Better inks, printers etc. can help. I didn't go that route, but it can be done.
Issue #2 is not really specific to digital negatives; you get the same effect with silver negatives, but digital negatives have the advantage that you can drastically improve shadow separation through digital curve corrections.

See if the reduced exposure makes a difference. I would certainly recommend exposing just enough to hit dmax and not a second longer to make the most of the tonal scale that the printer can manage.

There's something awesome about being able to use a wet printing process and get a good image from a digital capture.

Wait until you do the same with a large format sheet film negative

Having now tried several coatings with a puddle pusher and getting uneven results, I decided to use a brush for this.

For processes that have an actual solution for a sensitizer, a brush is always preferable IMO. Perhaps with the exception of Pt/Pd due to sensitizer cost...

 

[BHuij]

That looks pretty darn good!
Such are the woes of digital negatives
Maybe reducing exposure will help, but frankly I don't think you're ever going to be able to use the full tone scale of the printing process with this inkjet printer. I recognize your findings (albeit not necessarily with kallitypes, but other processes). These are twofold: (1) dmax of the inkjet negative is generally insufficient to create pure paper white and still get dmax. (2) you need to apply a *very* steep curve shape in the shadows of the print (clear/light zone of the negative) to get good shadow separation.
Issue #1 is just what it is. Better inks, printers etc. can help. I didn't go that route, but it can be done.
Issue #2 is not really specific to digital negatives; you get the same effect with silver negatives, but digital negatives have the advantage that you can drastically improve shadow separation through digital curve corrections.

I'm using an Epson P800, and managed to get paper base white and dmax with salt printing after some experimentation. Since salt printing is supposed to require even higher contrast negatives than kallitypes, I remain cautiously optimistic that I'll be able to get the full tonal range the process can offer without spending any more on digital negs or equipment to make them. Especially since I haven't even started trying to play with any of the chemical contrast controls available for kallitypes.

Wait until you do the same with a large format sheet film negative

Heh, I've been printing 4x5 for a few years. I still remember my first 8x10 silver gelatin print from a large format negative back in 2017. I had already been making enlargements from medium format and 35mm negs for years at that point, but was just absolutely stunned at the amount of detail in the print from the 4x5. Couldn't stop staring at it.

 

[koraks]

Ah that's right, well if you don't get paper white, then I'd make sure you don't have a chemical issue / fogging going on there. I agree that the density required to get pure white with salt prints should be enough for kallitypes. Provided you're hitting dmax with salt prints. I admit I'm still somewhat skeptical of the sufficiency of your p800 negatives, but it's difficult to accurately judge what's really going on over the internet.

 

[BHuij]

You make a really good point - if I don't get to paper base white, I need to rule out fogging. I think I'll place a small piece of opaque paper on my next test image to see if it matches the unsensitized border to make absolutely sure.

It's entirely possible I wasn't getting dmax on my salt prints. But I got a dark tone that looked the same as the blackest areas in all my "test strips" from earlier on, where I was specifically looking for max black through film base. In any case, if for no other reason than convenience, the last steps I will take to get acceptable tonality here are ones where I have to mess around with my printer inks or drivers. Hopefully it doesn't become a necessary evil; it's such an unappealing part of the process to me haha. Maybe if we hit that point, then I've finally come up with a compelling reason to buy an 8x10 camera

 

[koraks]

I have to mess around with my printer inks or drivers

I'm not sure if quad tone rip (QTR) still works with the P800, but it's worth trying - if you need to go there. Also the ink density settings in the Epson driver itself are fairly user-friendly. Between these two, you've got a lot of flexibility! Not quite as much as with film and developer, but still