The High School Chemistry book begins with a teaching about the scientific method. Simply stated, that is to 1) State the problem. 2) Gather observations. 3) Form a hypothesis. 4) Conduct experiments. 5) Evaluate the results.
1) State the Problem. Now I have a problem with two plates made so far. One of the plates is the Liquid Light bracket test and the other is the better work photo of the Field House that followed. The problem is that both have the same exposure, part of the bracket test has the same exposure as the Field House. The biggest part of the problem is that when I developed the bracket test I could not see any image form in the area that has the same exposure as the Field House, but when I developed the Field House photo it was observable.
Without the present study of the scientific method I would not pursue it. I went right past it and onto making large format images.
2) Gather Observations. I take a lot of notes when working. The notes are written again into a word processor document. I now have a format for all good photographs and some of the bad ones. A photograph fills the width of the page at the top. Under it, in bold, the title. The first paragraph under that lists the size, date, emulsion, camera, lens, and exposure, including the Foot Candle reading in incident light. The next paragraph is how the image was developed and fixed. A brief comment follows and the final paragraph tells something of how the plate was made.
Everything fits onto one side of one page. All photographs have the same format and information. It helps me figure out what is going on.
023 Frick field Wedge Test ...This plate was scraped twice, one end was thicker than the other.
025 Field house ...The emulsion must be very thin because it cleared so fast.
When I developed the Wedge Test, the part that was good didn't develop; it stayed white and I thought there wasn't an image there.
3) Form a Hypothesis. Thick emulsion may have a higher ISO than thin emulsion.
4) Conduct experiments. Make two plates, one thin and one thick with emulsion. Expose them both the same, develop them both the same, developing the thin one first by observation.
5) Evaluate. When I had developed 023, no image showed until it was cleared after 20 minuets in fixer, then the image showed to be the better part. I may have been overdeveloping thick plates! 025 cleared in 3 minuets.
I am guessing that thick emulsion will capture more light then a thin one and then hide the image under the unexposed excess white halides. Trees in the Frick Park Wedge Test photo have more gray details than the trees in the Field house photo. Development was one min in the Wedge Test and three min in the Field house. I will develop 2 min both new plates.
Two new plates were coated. The glass is new single strength with the sharp edges knocked off with a black diamond pad underwater. Two different methods of coating plates were used. One coating was applied thinly and the other was applied thickly.
The thin coating used glass edge strips of the same thickness, single strength, and a puddle pusher glass rod. The ends of the glass rod were wrapped with three layers of scotch tape. A thicker, double strength, glass strip was used to guide the glass rod pulling down emulsion over the plate. The glass set up was heated with a hair dryer. Emulsion was dumped onto one four inch edge and emulsion ran over the edge strip and the plate. Emulsion was pulled down over the plate in one slow pass then past the edge at the other end so to prevent emulsion from backing onto the plate. Excess was put back into the film canister; emulsion was kept warm for reuse on the next plate. The plate appeared light gray and dull.
About a third of a canister of emulsion remained and was used to coat the thicker plate. A marble slab was extended out over the edge of the table and a hot plate put under it. The stone end was heated to warm to the touch. Uncoated glass was preheated on the stone then held on my finger tips. Emulsion was about 110 F and carefully poured into the center. I was looking into the safe light in order to see to keep the glass level. No emulsion was allowed to pour off. I slowly tipped the plate this way and that so the emulsion ran into corners and edges. Then I rotated it some and placed it back onto the warm stone. While it sat for one minuet on the warm stone, I pushed the glass in circles with a popsicle stick. After I had counted to 60, I pushed the coated glass plate to the cold end of the stone without lifting it. It was allowed to solidify there. The plate appeared very white and shiny.