Carbon transfer reticulation

[koraks]

[Edit 9 July: problem solved by reducing temperature of the unmentioned hair dryer when drying the tissue after sensitization]

Not sure why, but a couple days ago I decided to give carbon transfer another go. I did some a couple of years ago, mostly from digital negatives, which worked OK. I'm now revisiting it with camera negatives; so far 4x5" (and perhaps I'll stick with that, in fact). So I have some experience with carbon transfer, but I'm by no means an expert.

I'm running into a problem I didn't use to have and I'm wondering if anyone recognizes it. I did some Googling but didn't find detailed clues. In short, the problem is reticulation, and it's quite bad at that. It seems to happen in the warm 'development' bath, but it happens so darn fast that it's hard to tell where/when it happens exactly. Here's two (poor, sorry) photos of a freshly pulled print (ignore the bubble in the top of the frame; it's an isolated glop pouring defect):
Full image, 4x5":


Closer up, at an angle:


It's actually pretty cool, in a way. It's just that I'd prefer it not to happen

Here's the details of my process:

Tissue:
* Pigment either India ink or acrylic paint (lamp black). Problem happens with both, with ink/paint concentrations of 1.5% ~ 3% w/v (concentrations does not affect the problem).
* Gelatin 8% w/v.
* Some bio-ethanol for degassing (perhaps 3% or so, probably less)
* Sugar 5%
Tissue is poured to 1mm wet height using magnetic frames.
I use blixed out expired RA4 paper (Fuji Crystal Archive) as a tissue support, which seems to work very nicely indeed (unless it's the source of this problem of course...)
Tissue size is a little over 4x5", 11cm x 15cm.
The above recipe used to work fine in the past.

Final support:
* Simili Japon etching paper, pretty heavy at around 260gsm or so.
* Sizing consists of 5% gelatin, poured to 1mm height just like the tissue, but obviously no pigment and no plasticizer.
* Hardening with either formalin or chrome alum, both added to the sizing just before pouring. The problem happens with both kinds of hardener.

Process:
* Brush sensitization with ammonium dichromate, 0.25 ~ 0.5ml of 0.5% ~ 2%, made up to 2ml with either bio-ethanol or acetone (problem exists with both additives).
* Exposure 6 ~ 20 minutes under UV tubes.
* Mating in properly degassed mating bath, at room temperature (around 22C currently); I let the final support soak for a couple of minutes (2 ~ 10 minutes) and the exposed tissue for about a minute. I tried a little longer (2-3 minutes) and a little shorter (ca. 40 seconds), which did not seem to affect the issue.
* After mating I let it rest for 20 to 60 minutes, with a sheet of glass on top of the sandwich and a weight on top of that. The resting time does not appear to affect the problem.
* Development occurs in water of approx. 50-55C (ca. 120-130F). Temporary support releases within 30 seconds and lifts off cleanly. I have no problems with frilling, air bubbles etc. (unless with severe overexposure, but let's put that aside).

The reticulation seems to show up mostly in the center of the frame, although in the example shown above it's pretty much all over the image. Like I said, it seems to happen in the hot water bath, particularly as the print is briefly (just for a single second) lifted out of the bath for inspection etc. It seems to happen instantaneously - or it has already happened before I get a chance to have a good look at the wet print, IDK. Evidently I have no way of seeing if it's already happened before the hot water bath...

What I know about reticulation amounts to the common view, i.e. it occurs when a wet gelatin emulsion experiences rapid cooling down. Evidently, the kind of emulsion I have in carbon printing is way more prone to it than camera film or silver gelatin paper - so I would by no means be surprised that this would happen with dramatic temperature transitions. The thing is, I don't subject the wet tissue to such transitions. Insofar as carbon transfer allows it, my process is fairly gentle. With perhaps the exception of the relatively hot development bath, but I have developed carbon transfers in way hotter baths (and then cold shock under a running tap!) in the past with no reticulation problems whatsoever.

What do you guys make of this?
I'll experiment some more over the weekend, see if I can get a grip on this one.

PS: this is a scan of the dry print shown above; it looks less dramatic than when wet, but it isn't as it should be.

[Ron McElroy]

There are some good carbon printers here, I am not one of them, and hopefully one will comment here. The developer bath seems to be too hot. I try for about 110F (43C) for developing. Another good source for carbon printing is Sandy King's group at https://groups.io/g/carbon

[Don12x20x]

Your developing bath is way too hot. Move it down to less than 112-115F. My co-author for the Carton transfer book, Sandy King, likes to keep his around 110F, but I use a bit warmer bath with no ill effects.

The effect you are seeing is that you have expanded the gelatin and when the temperature cools, it remains expanded. It's a thin film like a rubber balloon when hot, EXCEPT there is no memory. It just expands and does not contract proportionally to the heat.

The problem is similar to getting an air bubble trapped between tissue and support at mating -- the air expands during hot water development, stretching the film. Just popping the bubble leaves the thin gelatin film stretched and it will not go back to fit in the bubble's footprint.

Don Nelson

PS Extremely hot water will also cause highlight details to be washed away.

Not sure why, but a couple days ago I decided to give carbon transfer another go. I did some a couple of years ago, mostly from digital negatives, which worked OK. I'm now revisiting it with camera negatives; so far 4x5" (and perhaps I'll stick with that, in fact). So I have some experience with carbon transfer, but I'm by no means an expert.

I'm running into a problem I didn't use to have and I'm wondering if anyone recognizes it. I did some Googling but didn't find detailed clues. In short, the problem is reticulation, and it's quite bad at that. It seems to happen in the warm 'development' bath, but it happens so darn fast that it's hard to tell where/when it happens exactly. Here's two (poor, sorry) photos of a freshly pulled print (ignore the bubble in the top of the frame; it's an isolated glop pouring defect):
Full image, 4x5":


Closer up, at an angle:


It's actually pretty cool, in a way. It's just that I'd prefer it not to happen

Here's the details of my process:

Tissue:
* Pigment either India ink or acrylic paint (lamp black). Problem happens with both, with ink/paint concentrations of 1.5% ~ 3% w/v (concentrations does not affect the problem).
* Gelatin 8% w/v.
* Some bio-ethanol for degassing (perhaps 3% or so, probably less)
* Sugar 5%
Tissue is poured to 1mm wet height using magnetic frames.
I use blixed out expired RA4 paper (Fuji Crystal Archive) as a tissue support, which seems to work very nicely indeed (unless it's the source of this problem of course...)
Tissue size is a little over 4x5", 11cm x 15cm.
The above recipe used to work fine in the past.

Final support:
* Simili Japon etching paper, pretty heavy at around 260gsm or so.
* Sizing consists of 5% gelatin, poured to 1mm height just like the tissue, but obviously no pigment and no plasticizer.
* Hardening with either formalin or chrome alum, both added to the sizing just before pouring. The problem happens with both kinds of hardener.

Process:
* Brush sensitization with ammonium dichromate, 0.25 ~ 0.5ml of 0.5% ~ 2%, made up to 2ml with either bio-ethanol or acetone (problem exists with both additives).
* Exposure 6 ~ 20 minutes under UV tubes.
* Mating in properly degassed mating bath, at room temperature (around 22C currently); I let the final support soak for a couple of minutes (2 ~ 10 minutes) and the exposed tissue for about a minute. I tried a little longer (2-3 minutes) and a little shorter (ca. 40 seconds), which did not seem to affect the issue.
* After mating I let it rest for 20 to 60 minutes, with a sheet of glass on top of the sandwich and a weight on top of that. The resting time does not appear to affect the problem.
* Development occurs in water of approx. 50-55C (ca. 120-130F). Temporary support releases within 30 seconds and lifts off cleanly. I have no problems with frilling, air bubbles etc. (unless with severe overexposure, but let's put that aside).

The reticulation seems to show up mostly in the center of the frame, although in the example shown above it's pretty much all over the image. Like I said, it seems to happen in the hot water bath, particularly as the print is briefly (just for a single second) lifted out of the bath for inspection etc. It seems to happen instantaneously - or it has already happened before I get a chance to have a good look at the wet print, IDK. Evidently I have no way of seeing if it's already happened before the hot water bath...

What I know about reticulation amounts to the common view, i.e. it occurs when a wet gelatin emulsion experiences rapid cooling down. Evidently, the kind of emulsion I have in carbon printing is way more prone to it than camera film or silver gelatin paper - so I would by no means be surprised that this would happen with dramatic temperature transitions. The thing is, I don't subject the wet tissue to such transitions. Insofar as carbon transfer allows it, my process is fairly gentle. With perhaps the exception of the relatively hot development bath, but I have developed carbon transfers in way hotter baths (and then cold shock under a running tap!) in the past with no reticulation problems whatsoever.

What do you guys make of this?
I'll experiment some more over the weekend, see if I can get a grip on this one.

PS: this is a scan of the dry print shown above; it looks less dramatic than when wet, but it isn't as it should be.

[domaz]

I agree that too hot development water could be causing your issues. One thing though- I don't think I have ever encountered a temporary support lifting off at the 30 second mark by itself. That might signal an adhesion issue going on between the tissue and support. Usually bad adhesion is caused by too much soaking or sensitizer was not strong enough.

In any case, since you are using small tissues it might not be a bad idea to just use tray sensitizing, it eliminates a lot of variables of brush sensitization. Another idea to narrow things down might be to try transferring onto fixed out B&W paper (or fixed out RA4 paper I suppose?)- this takes one more variable out of the mix.

[Andrew O'Neill]

Firstly, I would revisit your development bath temperature. For me, that's just too hot! I Use the drift method. The temp starts at 45C. By the time the tissue is pealed, and print is cleared, the temperature is about 40C. If you still have the problem after lowering the dev bath temp, revisit your exposure. You could be giving too much. My mating bath is much colder than yours. I've settled on 15C. 3 minute soak. Also, my tap water tends to be a bit alkaline based. I always add a bit of vinegar or citric acid to the bath. Alkaline based water can have a detrimental effect on transfers. Maybe your tissue is soaking up too much water? If you are still getting it, then maybe it's the sizing. If could be related to one of these variables, or a combo. Carbon transfer printing involves a lot of tweaking due to many variables. Always only change one variable at a time. Keep notes. Have fun!

[koraks]

Thanks guys, that's really helpful. A few responses from my end:

* I'll try and reduce the development bath temperature. As noted, I didn't have issues with this temperature and higher in the past, but that's a few years ago and other parameters in my process are likely different now. Either way, I'll try a lower temperature and see how it pans out. The consensus is after all that the temperature is high and I do acknowledge this. Btw, I also think it's the reason why the temporary support releases so easily. It doesn't drift off all by itself at 30 seconds, but the edges to curl up and the support can be lifted off manually with ease.
* I might acidify the water a bit, although I'm not too worried about this with the water we have here. I do acknowledge that alkaline water will further soften a gelatin emulsion, so there's reason to this suggestion for sure.
* I have no problems with highlights washing away or symptoms that point towards tissue adhesion problems. In fact, apart from the reticulation thing, I've never had the mechanics of the process work so well as they do now! It's really a breeze compared to a few years back.
* I have tried transferring to RA4 paper, but the emulsion doesn't swell near enough to get the job done. A few years back I did transfer to RC and FB paper on occasion, especially when I had issues with the final support. As it is now, it seems I don't really have final support issues. In case the lower development temperature doesn't help, I'll be sure to try this route though!
* As to soak times during transfer: I tried shorter and longer, as indicated earlier, and all this didn't seem to impact the reticulation issue. I also see no signs of the tissue soaking up too much water; it remains somewhat stiff and feels just 'right', not bloated and wilted or anything.
* domaz, I have to admit I don't look forward to tray sensitizing; I did that once or twice way back and I just didn't like it. Also, I don't seem to be having any issues with uneven sensitizing (I know what to look for and how to prevent this), so I'll be saving this one really as a last resort measure.
* Don12x20x: thanks for the concise explanation of the mechanics of reticulation and what's going on here; very much appreciated indeed. Andrew, many thanks for chiming in; I secretly hoped you would All the others, also many thanks for your thoughts; they really help determining problem solving routes!

You guys rock - always knew you did, too.

[koraks]

Ok, looks like the problem is solved.

I lowered the development temperature to 42C - 43C (just shy of 110F), which didn't make much of a difference.

I then had the brilliant idea to review one of my eternal bad habits - the use of a hairdryer to dry sensitized alt. process media. This generally doesn't give me any trouble, but the other alt. processes I work with aren't gelatin-based...so I did some additional testing and sure enough, if I just leave the hairdryer at its coolest setting (which is lukewarm or thereabouts), the reticulation problem doesn't rear its head, and I still get fairly fast drying times without the tissue remaining too sticky.

Long story short: I'm an ass, but at least I figured out how big of one exactly

Here's two prints, still wet, tissue dried after sensitization using the hairdryer, but at the cool setting.


Warm-toned, using just India ink (if you're wondering about the non-image relief just visible in the dark area: it's the paper's watermark)


Cool-toned, using a mix of lamp black and phtalo blue acrylic paint

Thanks once more for everyone chiming in so fast; your responses surely helped me pin this down so fast!

[Jim Fitzgerald]

Wow, I would have never thought about a hair dryer being the problem. I thought I was impatient! I was thinking the water was way to hot as well. Glad you solved it.

[koraks]

Jim, great to see you're still here! I remember your Youtube videos from years ago. They really helped me along the way back then. I hope you're still going strong, making gorgeous large prints from silver negatives!

Yeah, I'm certainly impatient, and the hairdryer being the problem kind of surprised me as well. But I seem to be getting reproducibly good results now that I don't overheat my tissues, at least as far as I can tell by now. That is to say, the prints I've made today are much better than what I achieved the last time I did carbon transfers. They're really starting to sing, which is very satisfactory.

[Jim Fitzgerald]

Jim, great to see you're still here! I remember your Youtube videos from years ago. They really helped me along the way back then. I hope you're still going strong, making gorgeous large prints from silver negatives!

Yeah, I'm certainly impatient, and the hairdryer being the problem kind of surprised me as well. But I seem to be getting reproducibly good results now that I don't overheat my tissues, at least as far as I can tell by now. That is to say, the prints I've made today are much better than what I achieved the last time I did carbon transfers. They're really starting to sing, which is very satisfactory.

I'm quite busy teaching the process and working on several projects. Carbon printing is in my blood and it is all I do. It is surprising to me that the video still helps people. It was pretty raw. Patience and printing a lot gets you there. Keep it up. It is magic.