Re: Combotypes

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bi3@georgetown.edu
Date: 04/02/03-02:53:56 PM Z


Chris--

In response to your inquiry about "combotypes," this is something that I
do quite often (various combinations). Often I print one process with
the negative and the other with the positive.

* gum over cyanotype: A lot of my "gum" prints start with a first
printing in cyanotype. I never noticed any bleaching of the cyanotype
by the gum.

* gum over Van Dyke: This is another combination I like to use. Here I
think the gum changes the character of the Van Dyke (not a bleaching,
just something different).

* Van Dyke over Cyanotype: My prints in the latest traveling portfolio
used this combination. What follows is the information that I enclosed
with those prints (probably longer than you wanted).

>From time to time on the list there has been discussion of printing Van
Dyke over cyanotype. I've tried this in the past with little success
(except for one print which I could never duplicate). In my original
attempts, I was trying to print one negative in cyanotype and a
different one in Van Dyke, making a "double exposure," one image in blue
and the other in brown. For the examples in this portfolio, I tried a
different approach.

These prints all have a first coat of cyanotype, which was exposed and
developed. After drying, they were recoated with Van Dyke emulsion and
exposed under the same negative. They were then given a 2-minute water
rinse and put into the fixer ( 2.5% sodium thiosulfate). After a final
wash, they were hung to dry.

The first exposure produced a typical blue cyanotype print. Upon
recoating with the Van Dyke emulsion, the print fades, sometimes looking
worse than other times. After the exposure with Van Dyke, you have a
brown print (nothing of the blue print shows). The magic begins in the
fixer. The brown fades, revealing the blue underneath. If left in long
enough, all the brown disappears and you are back to a blue print.
Pulling it out part way and washing gives you a print with both blue and
brown. As with toning, you need to get the print out before it reaches
the state you want, since the action continues in the wash.

Rereading some posts from last year, I saw that garimo wrote that he
used the Van Dyke solution diluted 1:1 with water. Joachim wrote that
he used "extremely feeble concentrations of cyanotype." Keith Gerling
noted that "the most successful of my test images were with diluted
emulsion." These comments led me to try some prints with diluted
emulsion. As expected, the diluted cyanotype produced a lighter blue
print. The diluted Van Dyke gave good results in my first tests but
couldn't be duplicated.

Some of the negatives I was using for this experiment were ones I had
earlier printed as toned cyanotypes, so for comparison, I am including a
toned cyanotype. I also tried toning a cyan/Van Dyke print. This
lightens and softens the blues, but doesn't seem to change them to the
brownish tone you get with a regular toned cyanotype.

I thought I was getting interesting results with the first batch of
prints I made. I was surprised to find that the darkest areas bleached
back first. (In the enclosed prints, this meant that the sky reverted
to blue, which was what I wanted for this image.) When the submission
deadline was extended, I decided to make some more prints, so I would
have some to keep. However, in these the lights bleached out first.
(Another difference that I noted was that in the first series, after
fixing the Van Dyke, the blues had a decided green cast, which, however,
was lost after drying. This was not evident in the second series.)
What had changed? I had mixed new cyanotype for the first prints; that
was now a few weeks old, but the base cyanotype image looked normal.
For the second series, I mixed new Van Dyke emulsion; what I had used
before was about 7 months old and was mostly sludge. This is perhaps
what caused the difference. However, I think it is safe to say that
this combination of processes is one where controlled results should not
be expected. Just enjoy the surprises.

All prints are on Rives lightweight paper. Exposure was in full sun: 8
minutes for the cyanotype and 6-8 minutes for the Van Dyke. The
emulsions for both are the "traditional" formulas as in "Keepers." The
time in the fixer varied from 3 to 12 minutes.

1. cyan full strength Van Dyke full strength 1st series
2. cyan 1:1 Van Dyke full strength 1st series
3. cyan full strength Van Dyke 1:1 1st series
4. cyan full strength Van Dyke full strength 2nd series
5. cyan full strength (toned with tannic acid/sodium carbonate)

image: Joshua Tree National Monument
negative (actually positive): enlarged from 35mm onto Arista lith film

Suzanne Izzo


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