I got this wrong - it was in fact when a clear piece of plastic is used as a negative (it doesn't matter what the size is as long as it is big enough to be held in the negative carrier in the enlarger). The idea was that by putting food colouring (preferably dark colours), sugar/salt, and a cream such as vaseline onto the plastic because it would create an image on the enlarger when printed. The purpose of the vaseline is so that the salt or any powder used sticks and stays in place rather than falling off, the salt comes out enlarged almost like microscopic particles, the liquid shows up as a lighter part of the print because the dark colour under-exposes it (a lighter colour would be more dark or grey in tone).
Here is the test strip I did when I put salt onto the vaseline in my first attempt and a small amount of lightly coloured food colouring. I did it in sets of a second each, F11 because this was what I had been instructed to do and a contrast of only 3 on the filter. I thought that the 3 seconds worked best although I wanted to put the contrast up to 5, the 4 was slightly too dark and with more contrast would be even more over exposed.
Here is my first print - f11, 3 seconds and filter 5.
Here is another negative I made, I used more food colouring here. I put the light/f down to 16 to let the image have time to create contrast and put the timer up to 4.
Light 16 again, 4 seconds, 5 on filter, made another negative that didn't have as much food colouring so that I had less white blank space, more interesting composition.Very simple, lots of food colouring for most of it being white space, I moved the paper slightly during exposure so the black part which reminded me of a leaning tower or lighthouse. F16, 4 seconds, 5 filter.
I liked this one because the lighter food colouring mixed well with the salt and bubbles/gaps were formed, more midtones rather than contrast. F16, filter 5 and timing of 4.
I put the timing up to 6 on the same negative for a darker and more contrasted result which I preferred.
Here is a reversal of my negative - created by laying the original print down the wrong way up on top of paper ready to be exposed. Using light 8 for more brightness to shine through the paper for a contrasted exposure, a timing of 26 worked best, I followed instruction of around 20 but could tell this needed more exposure. I prefer the reversal because it reminds me of a microscopic image of the bloodstream or something else scientific in this aspect.
Here I started adding objects to the negative that was exposed, using the same method as a photogram but with the hand made negative in the enlarger. I used the timing appropriate for the negative - 4 on f16 and 5 on the filter, and lay the objects down onto the paper. The salt looked like a hill (as intended) and the people looked like they were at war with each other, also by sliding on it, the white looked like it is night and it has been snowing.
Using the same reversal timings and f/filter, this is my reversal, here it looked like day time instead, also the 'hill' didn't come out as well because it was a fairly dark grey tone on one side and this didn't contrast well when being reversed because it was too close to white.
In this one I attempted to make a clod in the sky with the dark food colouring and snow with the salt particle that would turn out white, below I arranged the men as it they were in the snow together in appropriate positions, e.g. the man shooting the man in the middle (far left).
My reversal, looked like they were underground, I preferred the first one because I thought the snowy night effect worked much better because it seemed more obvious and realistic.
I enjoyed this activity because it was something completely new to me, I liked creating a sort of scene with the materials although I did find it quite difficult to make something that clearly made sense, although the random compositions looked good because they looked as if they represented microscopic particles.