Camera Obscura

cam·era ob·scu·ra
/ˈkæmərə, ˈkæmrə/ɒbˈskyʊərə/
–noun
a darkened boxlike device in which images of external objects, received through an aperture, as with a convex lens, are exhibited in their natural colors on a surface arranged to receive them: used for sketching, exhibition purposes, etc.




"ancestor of the photographic camera. The Latin name means "dark chamber," and the earliest versions, dating to antiquity, consisted of small darkened rooms with light admitted through a single tiny hole. The result was that an inverted image of the outside scene was cast on the opposite wall, which was usually whitened. For centuries the technique was used for viewing eclipses of the Sun without endangering the eyes and, by the 16th century, as an aid to drawing; the subject was posed outside and the image reflected on a piece of drawing paper for the artist to trace. Portable versions were built, followed by smaller and even pocket models; the interior of the box was painted black and the image reflected by an angled mirror so that it could be viewed right side up. The introduction of a light-sensitive plate by J.-N. Niepce created photography."

Originally, the camera obscura was a large room with only a small opening to allow an image to appear against the opposite wall. This method has been around a very long time, with such a simple method of operation that it is really hard to place it exactly. Seriously, thousands of years ago in ancient china they had these things - not just since the middle ages, aka the 60's.




Larger camera obscuras built for amusement are all around the place; once a spectacle, the camera obscura structures of the last century are now a novelty to those who could simply pull out a cellphone and take a 10 megapixel image. Coming in a variety of sizes and shapes, these structures usually have a similar periscope-type lens to produce an image on a flat surface near the ground that allows people to see the image outside the enclosure.








Portable camera obscuras had been used for a long time as well to aid artists in painting more realistically. These devices typically used a single lens and a mirror to reflect the subject upwards onto tracing paper, which the artist would then outline, or, more simply, the artist would enclose himself in a wooden box with a lens to face the model, and the artist would use the tracing paper to outline the model. I feel like the man in the first image is compensating for something.





Camera obscura's can be made in a room, in a box, or in a shoe - as long as you have a dark space and an aperture to focus light, an image should appear on the other side. In our class, we were assigned to make our own camera obscura, something that I found to be an absolute joy as I love to build things.

My design used a +10 diopter from a lens filter and another piece of glass from an old lens, giving a very sharp, very nice view on the ground glass on the back of the camera obscura. The glass also allowed me to have a larger opening in the front, however my focal point was rather close to the lens, and the focusing range goes from 2 feet to infinity with a slide of about an ince, positioning the lens closer or further from the ground glass.

Photographic drawing salted paper: part deux

"How charming it would be if it were possible to cause these natural images to imprint themselves durable and remain fixed upon the paper! And why should it not be possible? I asked myself."
-William Henry Fox Talbot

During this part of our wonderful photo process class, we focused on making contact prints on self-made paper. We stuck to 3 different kinds of coating: Arrowroot, gelatin, and albumen, to create our "old-timey" photographic prints.

The wizard of the photographic drawing, William Henry Fox Talbot's discovery came between 1834-35, when he made the world's first silver chloride photo paper, and a process that could keep images from suddenly disappearing after being exposed to light again. Talbot's "photogenic drawing" paper was made in two steps: 1, fine quality writing paper was dunked in a weak salt solution and dried. 2, the paper became light sensitive by brushing on a strong solution of silver nitrate. After sensitized, the paper could be contact-printed, turning very dark in the sunlight. The paper was then soaked in a strong salt water solution to remove the paper's sensitivity to light, although bright light would still ruin the print. Herschel suggested that Talbot change to sodium thiosulfate, or "hypo" as the fixing material,which was a glorious choice, because the prints would now be fixed for real, and gave them white highlights instead of the faded opaque look from before. So in 1839, "hypo" became the preferred method of fixation, and Talbot's "photogenic drawing" paper became known as "regular photo paper".



Talbot noticed that his prints looked different than those elsewhere, and found out that gelatin in his paper made his images more red and brown than the other guys. He used neutral citrate to make his prints brighter and more red, and also looked into changing the binder from salt. The resulting discovery was a paste of arrowroot, a starchy mixture instead of a salty one that gave better color and more detail to the image. In fact, once arrowroot was discovered, single-salt papers were obsolete.

The Albumen print was invented in 1850 by Louis Désiré Blanquart-Evrard, and used the albumen found in egg whites to stick adhere silver to the paper. Eggs being so inexpensive, Albumen prints grew in popularity and were used world-wide for photographic purposes, and the shiny surface of the dried egg whites made the albumen print the right choice aesthetically out of the three.




In class, we experimented with 3 different types of silver-based photo paper, each made in lab under controlled settings.

The papers

Arrowroot coating:
4g arrowroot
119mL water
4g NaCl
.5g citric acid

To get the solution, an arrowroot paste was added to the NaCl and citric acid, and then ready for use.

Gelatin coating:
125mL water
1g gelatin
2.5g citric acid
2.5 g NaCl

The mixture was heated in a double boiler, and while warm, coated onto photorag paper.

Albumen coating:
500mL egg white
3mL vinegar
7.5g NaCl

The egg white was shaken (violently I may add) then let to sit in a container for two days. The coating process involved taking photo rag paper and floating paper on top of the surface of the albumen, avoiding bubbles of course, dried and re-coated.


After the paper coating ordeal (My group actually was kind enough to do it for me in my absence) I had 2 sheets of paper for each mix, the first with one coat and the second with two coats of each concoction. The albumen with two coats was shiny but the single-coated page was pretty flat.

Eat type of paper was exposed with the same process:
first, the dried albumen, gelatin, and arrowroot papers were coated with one coat of silver nitrate solution, dried, and then a second coat was applied and dried. In the end, I had a sheet of each paper with 1, 2, and 3 coats of silver ---- to make sure which worked best.

A 4x5 negative of a rose was placed on each paper individually, and they were exposed in direct sunlight for 5 minutes, washed, fixed, and washed again.




My best results were with albumen, with 2 coats of albumen and 3 coats of silver.




Good links on the subject:
http://albumen.conservation-us.org/library/monographs/reilly/chap3.html
http://steveanchell.com/index.php?option=com_content&view=article&id=34%3Asalted-paper&catid=15%3Aoutput-darkroom-and-lightroom&Itemid=39
http://chadjarvis.com/pdf/Reilly.pdf
http://books.google.com/books?id=k2gMwudsE3IC&pg=PA226&lpg=PA226&dq=19th+century+manuals+salted+paper&source=bl&ots=QFXXHcgbZC&sig=pQwH6pAjpWYhmqpBziCEeeUPdjQ&hl=en&ei=xGW3Tca5DYyltwe-qKzeBA&sa=X&oi=book_result&ct=result&resnum=8&ved=0CEoQ6AEwBw#v=onepage&q&f=true

The photogenic drawing

The photogenic drawing is a type of image making that uses silver nitrate and salt to create a positive-negative image on the exposed surface. Invented by William Henry Fox Talbot, the photogenic drawing was announced after the discoveries made by Daguerre with his own photographic process. Being reasonably inexpensive and simple, the photogenic drawing was a great advance in photographic image making, the process using basically the same end product that black-and-white photo paper is today.
With the light sensitive silver nitrate applied to the paper, an object or a negative is placed on the surface and allowed exposure until they seemed done, about 5 minutes depending on the mixture. Another method was placing the paper in a camera obscura, also giving an image.



The Procedure
In our experiment, we created our own photogenic drawings, and tested the varying sensitivity to light that different mixtures of chemistry would have.

1. 100% rag paper was labeled and adhered to a cutting board with masking tape for stability and organization
We labeled 12 sheets for different ratios of salt (NaC)l and silver nitrate (AgNO3), and different number of coatings of each
These are the mixtures used:
1. 1 coat 2% NaCl and 2 coats 12% AgNO3
2. 1 coat 2% NaCl and 2 coats 5% AgNO3
3. 1 coat 5% NaCl and 2 coats 12% AgNO3
4. 1 coat 5% NaCl and 2 coats 5% AgNO3
5. 2 coats 2% NaCl and 2 coats 12% AgNO3
6. 2 coats 2% NaCl and 2 coats 5% AgNO3
7. 2 coats 5% NaCl and 2 coats 12% AgNO3
8. 2 coats 5% NaCl and 2 coats 5% AgNO3
9.2 coats 2% NaCl and 1 coat 12% AgNO3
10. 2 coats 2% NaCl and 1 coat 5% AgNO3
11. 2 coats 5% NaCl and 1 coat 12% AgNO3
12. 2 coats 5% NaCl and 1 coat 5% AgNO3

2. Salt solution was applied with a brush and then allowed to dry, either 1 or two coatings
3. Silver nitrate solution was applied with a brush and allowed to dry, either 1 or two coatings
4. A variety of objects were placed upon our paper, including a zippo lighter, car keys, scissors, and pens
5. The paper was set outside in daylight for a 7 minute exposure time, and then brought inside
6. The sheets were peeled from the holder, washed in strong salt water, and then washed in cold water.

Results

We found that more salt is bad for the paper, as it gives less sensitivity to the silver, and the resulting image is very light, where too much silver or not enough salt leads to a dark, overly sensitive and ugly image.



Here are more resources on the subject:
http://www.mhs.ox.ac.uk/features/ephotos/pdtypes.htm
http://www.sugimotohiroshi.com/PhotoDrawing.html
http://www.edinphoto.org.uk/1_early/1_early_photography_-_processes_-_photogenic_drawing.htm

Anthotypes: First Project

Photograph by SILVINO GONZÁLEZ
Check him out: http://bipolaryourmung.wordpress.com/2010/12/16/anthotypes-update/

Our first topic in class was the anthotype: an image making process developed by Sir John Herschel in the early 1840's. The process paper to be coated with a light-sensitive extract obtained from various organic material, more commonly leaves and berries, and exposing the coated surface to light with a desired image overlay, creating a contact print. The name is derived from the Greek word antho, meaning flower. For the completely exposed surface of the paper, color will bleach away as the sunlight destroys the color of the juice. The covered part of the surface will not be exposed to the UV rays of the sun, and the color will remain, resulting in an image with a positive image. While the exposure takes a long time, the resulting image can be quickly destroyed if exposed to more sunlight, due to the now vulnerable and previously-protected coating.

Lab work: In my class, my team and I created an experiment to test what light sensitive materials: Raspberry or spinach juice; and which binder: water or alcohol; would create the best image when used as a coating for an anthotype.

The process involved 2 coats of light sensitive material on 6 sheets of bristol board, using 6 different coating mixtures:
1. Sheet one was coated with a ratio of 1:1-filtered raspberry juice and distilled water
2. Sheet two was coated with a ratio of 1:1-filtered spinach juice and distilled water
3. Sheet three was coated with a ratio of 1:1-filtered spinach juice and filtered raspberry juice mixture, and distilled water
4. Sheet four was coated with a ratio of 2:1-filtered raspberry juice and alcohol
5. Sheet five was coated with a ratio of 2:1-filtered spinach juice and alcohol
6. Sheet six was coated with a ratio of 2:1 - filtered spinach juice and filteres raspberry juice mixture, and alcohol

7. All sheets were covered in some locations, covering the different coatings
8. Sheets distributed to group members
9. All sheets were set up and places in sunlight for exposure.

I received the sheet coated with 2 parts spinach juice, and 1 part alcohol. I placed a cut-out of a supermodel on to block some light and allow other light to expose the coating. I placed it in a window that gets the most light in my house, and taped a black board behind it to prevent strange reflections through the glass. I hope for an image of a bikini-model within the next few months.

Here is an image of my current set-up:




Hopeful!

Here are some good links to learn more about the anthotype process, and help you make your own:

http://www.alternativephotography.com/wp/processes/anthotypes/anthotype-process

http://193.166.40.90/?cat=18

http://www.f295.org/Pinholeforum/forum/Blah.pl/Blah.pl?m-1187767675/