Carbon Transfer Video

Jim Fitzgerald

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I have my own opinion as to the working methods for carbon transfer. As a dedicated printer and teacher it is nice to see the process. I feel that one really only needs to see how the process is done and then read everything that has been written to learn this process. Printing is learning. I could not agree more with Charles and Bob on the safety issue of wearing gloves during the process. Why take the chance? it seems foolish to me. I have the same opinion and I have expressed it to my friends who pour wet plate. What the hell are you thinking?
 

holmburgers

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The video does an excellent job of showing the relief, something that is lacking in a lot of coverage on carbon.

What factor(s) is most important for controlling relief? Pigment concentration?

3 heavy hitters in the carbon world are all in agreement on the safety issue; I hope it can be left at that...
 

JBrunner

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holmburgers said:
3 heavy hitters in the carbon world are all in agreement on the safety issue; I hope it can be left at that...
Click to expand...

Yes, so let's leave it. Including my post, which is the last on the OT subject in this thread. In other words, we don't need to discuss that which we are not discussing, but rather the former discussion which isn't relevant to the other discussion which heretofore shall no longer be discussed. Thanks guys.
 

Vaughn

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holmburgers said:
...What factor(s) is most important for controlling relief? Pigment concentration?...
Click to expand...

Pigment concentration -- the lower the better. But that also reduces contrast, so one compensates by using a negative with a very wide tonal range and perhaps reducing the sensitizer strength.
 

Marco B

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Andrew O'Neill said:
Here is a video I made. It's an overview of the carbon transfer printing process.

http://www.youtube.com/watch?v=EmpTgDlsr3o
Click to expand...

I have added your video to the (there was a url link here which no longer exists) (which just uses links to the original resources, videos are not stored on the APUG servers):

You can find it here:
(there was a url link here which no longer exists)

I hope you don't mind
 

CMB

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holmburgers said:
What factor(s) is most important for controlling relief? Pigment concentration?
Click to expand...

The thickness of a carbon relief image is determined by the depth of penetration of light into the sensitized emulsion and is thus a linear function of the exposure time and intensity of the printing light. When the layer contains pigments, the relative thickness of the relief is proportional to its transmission optical density. Thicker coatings which require longer exposures to reach the "burn thru" point (beyond which the light reaches the supporting base and the entire layer becomes water insoluble) will exhibit a greater relief than thinner coatings with lesser exposure time. The maximum possible thickness is limited by the absorption of actinic light by the upper layers of the coating.
 

holmburgers

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Am I right in thinking that a thick coating should have a relatively low concentration of pigment to achieve a high relief? Otherwise it seems that penetration would be too minimal to fully utilize the thickness, without also muddying the highlights.

Assuming we have 2 tissues of equal pigment concentration, but differing thicknesses; won't the exposures have to be identical to achieve the same tonal values in the mid & high-tone range? That would seem to support the idea that a thicker coating should have less pigment if you want high relief.

Basically I'm trying to understand the interplay of coating thickness & pigment concentration on contrast & range.
 

Vaughn

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Correct -- thickness of the gelatin layer of the tissue does not directly affect relief, exposure nor contrast. A negative printed using the same exposure, same pigment concentration, and same sensitizer concentration on tissues of different thicknesses should yield identical prints.

I pour thick tissues of low pigment concentration, use negatives of very high contrast, and use a high sensitizer concentration (for 8x10 -- 5ml of 8% of AD, diluted 1:2 with acetone).

The lower the pigment concentration, the thicker the layer of exposed gelatin will have to be in order to achieve a rich black...so one will have a minimum exposure time that will expose far enough down into the tissue thru the base+fog of the film in order achieve that black.

The concentration of the sensitizer affects how quickly the shallower highlights and mid-tones harden, thus controlling contrast, relative to the native contrast of the negative. High concentration of the sensitizer allows for more image formation in the upper portions of the tissue as the light dives down deeper into the tissue -- thus lower contrast.
 
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Vaughn

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The video does give one a very good indication of the relief. Of course most of what we saw will shrink down as the print dries, but it will also tighten up. It was a hint of this relief in my first wet prints (the prints would dry down to no relief) that got me into pushing the process to keep the relief after the print dried.

During the same time, I was gaining interest in working with the light in the redwoods when the sun was burning through to the forest floor, yet one had significant areas of can't-see-into-them blacks. I had photographed for many years in the redwoods with a cloud cover or fog. Wonderful contrast that easily matches the silver gelatin materials. Like photographing under a big soft box. But how to photograph on the sunny days without bumping into the limitations of silver gelatin paper?

So how great it was to have a process that eats any contrast I throw at it -- just when I began to be attracted to landscape scenes of high SBR*...and the more contrast in the negative, the greater raised relief I seem to be able to get on the carbon print.

So -- Did I jump into carbon printing because I was too lazy to learn how to properly control high contrast for silver printing?

Vaughn

* Scene Brightness Range, I think I am using it correctly. Basically using the numbers off my Pentax Digital Spotmeter -- I'll get Low/High readings of , 4/10, 10/16, 4/12, 5/15, 3+/12, and so on. So I expose for the shadows and let the highlights rip. I tweak the dilution and time of the developer (Expert drum 3005) to avoid blocking the highlights...usually on the side of pushing the film a bit. Not very scientific. And can get me into trouble when I stick my head out from under the redwoods! :eek:
 

Louis Nargi

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Thank you, this was very interesting. I have been thinking of learning this for a while. Thanks again
 

Vaughn

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Leigh B said:
??AD??

- Leigh
Click to expand...

Sorry, "insider slang" -- Ammonium dichromate -- as opposed to PD (Potassium dichromate).

Right now I have three batches of glop in the warm water bath (a toasty 115F). Glop is another insider term -- used as the nickname for the melted solution of gelatin, sugar, and carbon (or equivilent). "Glop" is rumored to come from the sound of a large quantity hitting the floor.
 

Leigh B

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Vaughn said:
Sorry, "insider slang" -- Ammonium dichromate -- as opposed to PD (Potassium dichromate).
Click to expand...
Thanks, Vaughn.

I've gone over the video and some of the written material, and have picked up most of the terms, but had only encountered potassium dichromate previously.

- Leigh
 

Vaughn

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They (AD and PD) can be used with identical effects, though some adjustment must be made to get equivilent dilutions. PD weighs a little more per molecule so a little more must be added by weight to be the same strength as AM. PD weighs more per mole than AD, might be the way to put it...the same weight of AD and PD would give us more molecules of AD than PD.

Also I believe AD will go to a higher dilution than PD, if one needs to reduce contrast that way. AD reacts less with some solvents when spirit sensitizing, but this is a bit confusing to me. Neither will react with acetone, which is what I use, so it is a non-issue. PD is usually cheaper... So one has choices.

PS...hope I am not "lecturing" any chemisty-types out there! Just getting it straight in my head!
 
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Leigh B

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Hmmm... Lots of variables.

AD seems to be a bit more dangerous than PD, in that it's explosive, which PD is not.

What are the advantages of using it?

Thanks.

- Leigh
 
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CMB

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Leigh B said:
Hmmm... Lots of variables.

AD seems to be a bit more dangerous than PD, in that it's explosive, which PD is not.

What are the advantages of using it?

- Leigh
Click to expand...

The high solubility of ammonium dichromate (as compared to potassium dichromate) in water permits high concentrations in gelatin layers without crystallization taking place when the coating is dried . This higher possible concentration level provides a greater sensitivity (faster printing speed) of the carbon tissue. Also, the pH of AD is lower than PD which results in higher sensitivity. Carbon tissue sensitized with a 2.5 % AD has the same speed, contrast and keeping quality as a 3.5% PD.
 

Leigh B

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Good info.

There seems to be a lot of interaction among the various components of the process.

Thanks.

- Leigh
 

Bob Carnie

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Keep it coming Vaughn,,
we are experimenting with Carbon here, Sandy King spent another week with us and for me all info is important as we are having some problems with this process which I attribute to the normal learning curve.
I love Andrews video and would love to see him do each segment of his workflow as this is very helpful for us in our efforts.
When I first started printing silver, there were no videos, no internet and **yes I slept in an Igloo and walked 5 miles in snow to a one room school**
For the younger workers here I cannot tell you how envious I am that you can get all this information at the click of the keyboard.
So without side lining this thread, I do have a question or observation for all of you to consider and throw in your 2 cents.

IMO - Silver is probably the most wonderful process and the range of tones is incredible with good technique.

IMO - also I will say that Pt Pd has probably the richest tonal range of all process from the mid point up to the beautiful highlights.

IMO- also after seeing Sandy Kings prints, on numerous occasions I will say that Carbon has the most wonderful tones from the upper mid tones down to the deepest shadows.

OK so what I want to do is combine (warm} Pt Pd as the main hit of image to define delicate highlight detail and then over print {black bluecyan} Carbon to define the shadows. think tri tone silver prints and you will see where I am going with this workflow .

We are actually doing this right now and am aware of the pitfalls but would love to hear from you all what you think are the pitfalls and how you would get around them.:munch:


 

Jim Fitzgerald

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Bob, I think you may have to try pin registered multi layered carbon printing. Gordon Chapple was doing this and his prints were very unique. Sandy has seen them as has Vaughn. I think you can achieve what you are after with the proper blending of the right pigments in a single transfer. In my own work flow I have successfully matched Pt/Pd prints in tonality. I agree with you assessment of silver, Pt/Pd and carbon to a point. The rich smooth highlights in the first two processes can be achieved in carbon but it is very difficult to do. I have had some success printing high key images but I will admit that Pt/Pd is still a better choice until I refine my process a bit more. With carbon I feel I am not limited in any way. One just needs to refine the work flow. True for any process. I think carbon has the most potential IMO.
Now that is just my .02 worth. It sure is fun pushing the process.
 
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