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Max Hao
11-Nov-2015, 09:35
The recent carbon print I made had white background, but pretty bad mottling. Any hint on what caused this please?
Cheers,
Max

Jim Fitzgerald
11-Nov-2015, 09:41
Max, generally this can be caused by excess humidity, insufficient dry time after sensitizing and other factors. Hard to say without more details. Also, highlight values are the hardest to clear even for the most advanced carbon printer. My advice is to not use a white background. This will reduce problems.

John Jarosz
11-Nov-2015, 11:37
Those grapes look pretty nice. Don't get me started on clear grey skies or huge expanses of white snow. Jim is correct!

koraks
11-Nov-2015, 11:47
I have had my fair share of transfer issues that degrade highlights in a similar way. Usually due to uneven/inadequate sizing of the final support paper, insufficient pressure during mating, soaking too long in the transfer bath or mating too briefly.

Jim Fitzgerald
11-Nov-2015, 12:01
Large expanses of white or clear areas are difficult to print but not impossible. For the longest time I was not happy with this image until I realized that this type of image is very difficult to print in carbon transfer. Everything has to be perfect. It is very hard to tell from this but the whites are as good as it can get. There is a little modeling along the left edge but the snow texture and detail is there.

Max Hao
12-Nov-2015, 00:07
Thanks for the advice. The tissue was about 6 months old, but I guess a little longer drying time after sensitizing should help. I noticed after exposure the tissue somehow stuck with the film, but luckily didn't ruin the film.

Jim,
Very nice snow scene.

Jim Fitzgerald
12-Nov-2015, 07:47
Max, if the tissue sticks then check your humidity. When the humidity is high and if you are using a thick tissue you will need to increase the dry time.

The snow shot from Yosemite is a favorite, glad you like it.

Wally H
12-Nov-2015, 15:17
OK So I spent the afternoon at the Stieglitz exhibit at the Art Institute in Chicago. He has a few carbon prints but Julia Margaret Cameron has a bunch of carbon carbon prints done in the late 1800's. Yards, no, acres of highlights.
While a little soft by Fitzgerald/Jarosz standards, completely blemish free. Anyone hazard a guess how they were able to do it then but it is so difficult now?

Andrew O'Neill
12-Nov-2015, 16:19
I have found that after I abandoned the quest for maximum relief years ago, and using a higher pigment load, stronger sensitizer, less exposure, there was an improvement in highlight detail... but still not near the detail I can get with kallitype printing. But, a marked improvement with both film and digital negatives, with film negatives having a slight edge.

John Jarosz
12-Nov-2015, 20:55
People master the technology of their era. Fine woodworking in the 18th and 19th century amaze us who have access to power tools. The only way to make a fine B&W print in the late 19th century was carbon, yet we are left wondering how anyone in that primitive age could master a finicky process. And so it goes with engineering as well, whether it's the pyramids or Gothic cathedrals. Maybe having fewer distractions was a benefit for craftsmen/artists, more so than we understand.

Something else: Historical processes were done with common materials of that era. We are re-inventing or re-engineering those historical processes with materials that are common to our era. Carbon printing may have been easier with the materials of their day rather than ours. We always tend to think that any process done today would have to be easier with our technology rather than the materials of a previous era. Maybe not. I can tell you that contemporary descriptions and accounts of the old processes are not what we would call complete. When I started researching the carbon process and tried to replicate the results of processes documented in the 1880's I found much information was missing, or materials were described in the vernacular of the day so I had to interpret what I thought was meant by the description. And that interpretation was not always correct.

I have a carbon print by Annan made in the late 19th century. While it's a beautiful print, it's does have a defect common to carbon prints in the highlights. He had the same problems we have today. Maybe they were more accepting of defects that resulted from the hand-made aspect of the process. We are so accustomed to perfect materials from machine made technology that for us those kinds of defects are simply unacceptable. We always toss the imperfect ones. And while some of their prints were perfect, some were not.

Of course, it's all my opinion - not necessarily facts (except the part about the Annan print).

Randy Moe
12-Nov-2015, 21:15
The recent carbon print I made had white background, but pretty bad mottling. Any hint on what caused this please?
Cheers,
Max

Those grapes look wonderfully 3 dimensional on a computer, I don't even think about the mottling. Don't tell. I won't ask. :)

Max Hao
13-Nov-2015, 00:26
Those grapes look wonderfully 3 dimensional on a computer, I don't even think about the mottling. Don't tell. I won't ask. :)

Thanks Randy. Now that room temperature is perfect for carbon, more to come!