Carbon printing process question

[MTGseattle]

I had to laugh earlier, someone on Amazon had a roll of 616 in 1/2"x 72 yards priced at $1572.00

 

[TheYoungPretender]

Has the supply of DAS in smaller quantities completely dried-up now? I'm guessing going for 250g is the only option unless you are looking to import in large quantities from asia?

 

[koraks]

Has the supply of DAS in smaller quantities completely dried-up now? I'm guessing going for 250g is the only option unless you are looking to import in large quantities from asia?

Yes, it seems that way. Calvin is currently your best bet in the EU. In the US, there's also Secant.

For masking, I prefer rubylith sheets that I cut masks out of; only remove the red film and leave the backing material in place. This creates no bumps or fuzziness. The masks are rigid and durable when done this way, so I only have a few and keep reusing them. I used narrower strips in the past, but the bigger sheets are far more convenient IMO. Rubylith can still be found on eBay; it's expensive these days, but since the masks are reusable, the cost per print ends up being negligible.

 

[MTGseattle]

I've been "consumed" by other life events of late and my journey towards Carbon printing is still lacking 1or 2 chemicals and some odds and ends. I like the sound of the full-sized masking sheets.
Freestyle had some of the rubylith 616 tape on clearance recently, I'm not sure why I didn't pull the trigger as it looks to be all gone
It seems like 1/4" to 3/8" glass is somewhat expensive these days. I need to scan my local classifieds better for that. The glass shop we use for shelves and such doesn't keep scrap around, and quoted me $150 for two 1/4" eased edge sheets in 16x20 size.

 

[koraks]

Why not start out a little smaller and with thinner glass? Then scale up if/when you need it and once you've got the basics down. I do must of my testing with 4x5 to 5x7 sized prints. I find this more convenient and ultimately quicker than practicing on larger formats.

 

[MTGseattle]

My exposure unit will accommodate the larger glass, and I can certainly print smaller with the larger glass, but not the inverse.

As to the other factors, The Yupo or whichever temporary support, the final paper, the glop, etc. will all exhibit the same properties whether I start with 4x5 or 8x10 right? There is a bit of wisdom to ironing out a process on "less" materials not to mention I have quite a few more 4x5 negatives to mess with.

I do need to contact our other former glass shop as they are bigger and may have scrap around. I could certainly drop back to 11x14 glass.

 

[Rick A]

My exposure unit will accommodate the larger glass, and I can certainly print smaller with the larger glass, but not the inverse.

As to the other factors, The Yupo or whichever temporary support, the final paper, the glop, etc. will all exhibit the same properties whether I start with 4x5 or 8x10 right? There is a bit of wisdom to ironing out a process on "less" materials not to mention I have quite a few more 4x5 negatives to mess with.

I do need to contact our other former glass shop as they are bigger and may have scrap around. I could certainly drop back to 11x14 glass.

I used to use fixed out glossy RC paper for temporary supports, now I use fixed out X-ray film. You can use larger size tissue or cut down to what ever size you need. I use 5x7 to make tissue for 4x5, 8x10 for 5x7, and 11x14 for 8x10. I pour my tissues oversize and mask my negatives with rubylith sheets.

 

[koraks]

The Yupo or whichever temporary support, the final paper, the glop, etc. will all exhibit the same properties whether I start with 4x5 or 8x10 right?

Yes, certainly. Everything is heavier, more unwieldy and basically more of a pain if done big. The net result is that you'll work slower and struggle with more silly things that hold back your progress on the really important things (e.g. contrast control).

I used to use fixed out glossy RC paper for temporary supports, now I use fixed out X-ray film.

I've done both, now use Yupo; I find Yupo more convenient than repurposed film & RC paper (I've also tried various types of polyester/polyprop sheet, copier paper, fine art paper etc. for tissues). I have two sizes of Yupo sheets for tissues since my printing is all done on two sizes, too (4x5 & 8x10) and I reuse the Yupo sheets. Very efficient.
One reason I prefer Yupo is that it's fairly thin and yet sturdy enough; both x-ray film and RC paper are a little stiffer and that makes the peeling off part in the water bath a little trickier. It still works fine of course, but the odds are slightly bigger of scraping off a bit of image with the edge/corner of the tissue while lifting away the tissue support. It's not a big problem of course.

 

[Rick A]

Yes, certainly. Everything is heavier, more unwieldy and basically more of a pain if done big. The net result is that you'll work slower and struggle with more silly things that hold back your progress on the really important things (e.g. contrast control).



I've done both, now use Yupo; I find Yupo more convenient than repurposed film & RC paper (I've also tried various types of polyester/polyprop sheet, copier paper, fine art paper etc. for tissues). I have two sizes of Yupo sheets for tissues since my printing is all done on two sizes, too (4x5 & 8x10) and I reuse the Yupo sheets. Very efficient.
One reason I prefer Yupo is that it's fairly thin and yet sturdy enough; both x-ray film and RC paper are a little stiffer and that makes the peeling off part in the water bath a little trickier. It still works fine of course, but the odds are slightly bigger of scraping off a bit of image with the edge/corner of the tissue while lifting away the tissue support. It's not a big problem of course.

YMMV, everybody has their own method, whatever works for you.

 

[Andrew O'Neill]

I have used fixed out RC, and XRAY film as a tissue substrate, but prefer Yupo. Two reasons: I can cut it to whatever size I need. It's quite durable. Some of them I've been using repeatedly for over a decade.

 

[Vaughn]

I started out by raiding the trash can at the college darkroom for their rejects on 11x14 litho film to use as tissue support. Some interesting images on them at times. Litho film (from Freestyle) was nice because it has the stability and toughness of sheet film, but only 0.004" thick instead of sheet film's 0.007"...made it for nice removal in the hot water.

Plus it was already fixed, and it was good to remove it from the waste stream for awhile...and free.

Now I tend to coat 12.5"x19" sheets of Yupo (86 wt). Then I cut it down to the sizes I need (I print 4x5 to 11x14). Pouring big tissues just saves time. If I sensitize a whole sheet, then cut six 6x8 tissues from that sheet, all six tissues will be identical. I have 14x17 xray film I can also fix-out, but I cannot get two tissues for 8x10 out of it. The size of one of my batches of glop (about 850ml) is just enough for three 12.5x19 sheets of Yupo...which is the number I have room for at one time.

Andrew -- have you noticed any difference in the prints or the processing of the prints between using Yupo with its bright-white surface, and using a clear tissue support (xray film, etc) with a black backing in the contact printing frame? I'm just wondering if enough UV would bounce off a white final support and back into the gelatin during exposure to be significant.

 

[MTGseattle]

OK. DAS? Was it an existing compound, or did Calvin Grier develop the stuff? A google search without carbon printing as a modifier kept returning Diallyl Sulfide.

$300!?? Holy fudge. I think I will do things the old-fashioned way.

 

[koraks]

DAS? Was it an existing compound

Yes, it was used for making the shadow mask of CRT's apparently. The price is kind of high because it's now a niche chemical that's only produced in relatively small batches.

I think I will do things the old-fashioned way.

YMMV. I'm never going back to dichromate! DAS is expensive, but the cost per print isn't too bad, and more importantly, I think it's more than worth it. It's a quicker, more predictable and more consistent workflow.
I started out with dichromate, too, btw. It has its merits - more easily available as long as you don't live in Europe, it's a little more forgiving in terms of highlight transitions, you can do single transfers with it and still get rid of the stain, and it has a very pretty orange color in solution.

 

[MTGseattle]

There's something to be said for the lighter environmental cost as well. I definitely like the sound of the benefits DAS provides. Still, I will press-on and learn the "common" method and then decide if I should change things up since I already have dichromate on hand.

 

[Vaughn]

Back in the day, there was commercially available DAS-sensitized color tissues for full-color carbons -- UltraStable was the maufacturer (until 1999, I think). DAS is a stable sensitizer that is getting a lot more attention now as a replacement for the dichromates, which are are toxic and banned in Europe. It does have some issues and limitations, some of which work-arounds have been found. My impression is that DAS works nicely with color carbons (thin colored layers rather than one thick one), and with inkjet negatives, as the negatives can be designed to fit best the characteristics of the DAS.

 

[koraks]

My impression is that DAS works nicely with color carbons (thin colored layers rather than one thick one), and with inkjet negatives, as the negatives can be designed to fit best the characteristics of the DAS.

Sort of; not quite though.
The reason why thin tissues, color and DAS are associated seems to be because this is how Charles Berger (who introduced UltraStable / DAS carbon in the early 1990s) used it, and after him Tod Gangler and presently people like Calvin Grier and Michael Strickland work. However, the one thing their workflows all have in common is that they use imagesetter negatives. This is crucial in making DAS work with thin tissues. There's nothing inherent to DAS that makes it like thin tissues; in fact, it's very much the opposite! The hardening action of DAS appears to be much less vigorous than of dichromate, which means that highlight retention is far more challenging with DAS than with dichromate. Due to this, it's in fact easier to work with relatively thick and low-pigmented tissues when using DAS in combination with continuous tone negatives. I've written about this more extensively here: https://tinker.koraks.nl/photograph...of-das-carbon-with-continuous-tone-negatives/ This particular blog was the culmination of several months of systematic experimentation, and my net conclusion is (and still remains) that dichromate is more forgiving when it comes to rendering delicate highlights. It's more challenging with DAS.

The reason why color printers 'get away' with thin tissues is because they generally use imagesetter negatives, which largely avoids the tonal threshold problem. I print exclusively from in-camera negatives, and then the tonal threshold is a very, very real issue and it's far more of an issue with DAS than with dichromate. The solution is to use a relatively low-pigmented tissue that's also fairly thick (otherwise no satisfactory dmax can be achieved) - very much like how you're printing, Vaughn - only I don't take it quite as far as you do because I don't require the relief.

In fact, speaking of relief, this is a bit of an issue with DAS. The 'default' way of printing with DAS is a double transfer. This suits me fine, because it means my images don't end up mirrored. But the drawback is that virtually no relief remains on the dried print as the image effectively sinks into the sizing of the final transfer paper. In my printing, I'm not after relief so I don't mind, but for you, Vaughn, this would probably be a firm dealbreaker.

Here's a small snippet from the relief on a drying DAS print after the second transfer; at this stage, the relief is already virtually gone, but it's still a bit visible:

In the dried print, it's totally gone; here's a section of a nearly identical print, but after drying:

This is photographed at an angle (hence the odd contrast, which is due to the paper texture) and as you can see, there's absolutely zero relief.
Btw, the illustrations above are from the prints also shown here: https://www.photrio.com/forum/threads/showcase-for-your-hcwps.199853/post-2799621

In principle the relief is there alright with DAS; it's just masked by the double transfer process. Here's a small section of DAS carbon on glass, backed with another gelatin layer with gold print to make a kind of orotone; this is looking at the front of the glass:

The back of the plate where the image actually is (with the gold layer on top of it) still shows the relief of the image:

It's also certainly true that with DAS, you really have to tailor the negative to the printing process. With dichromate, you can vary a heck of a lot by changing pigment load and dichromate concentration, going pretty much in any direction you like. With DAS, you can vary pigment load only to an extent and varying sensitizer concentration effectively doesn't do f-all. So you have to work on the negative, which is why I've been doing a lot of experimentation with chromium intensifier - yes, the irony is that I'm using dichromate to accommodate my DAS habit! I don't really mind because (a) I have a decent stock of dichromate left, (b) I don't need nearly as much as when I used it as a sensitizer, (c) it's easy to reduce the chromium VI to far less nasty chromium III when you're done and (d) since negative intensification all happens in a tray without any need to ever touch the negative while it's in there, the safety risks are also much less than when developing a dichromate-sensitized carbon print. I've also written a pretty recent blog on this dichromate intensification business here: https://tinker.koraks.nl/photograph...ium-intensifier-for-silver-gelatin-negatives/

Sorry for the long message; I've spent quite some time on getting my DAS workflow to where it is now and in the process I've confirmed a few things others already said (but you sometimes have to experience it with your own hands before it really makes sense), and also deepened out a couple of things that others were very brief about or didn't appear to realize very well. I've written a lot on this in the hope that it saves some people the trouble; it's very much like Calvin's writings, but he has so far not really covered this from an angle of in-camera, continuous tone negatives because of his (understandable) commitment to a digital workflow and imagesetter negatives.

 

[MTGseattle]

I for one appreciate the added information.