The project is to use x-ray film (ortho, double-sided, quite fast) to experiment with coloured starch pixels. The autochrome method from the start of the 20th century.
Low cost, that is:
- using kitchen quality potato starch.
- various non-specific dyes purchased at a sale last week.
- lamp black from a bad candle - seasonally appropriate.
Process is:
Stripping one of the emulsions from the x-ray film in a safelight.
Preparing the 3 separate dyed starch components.
Mixing according to the old lumiere recipe.
Covering the clean side of the film.
Filling "holes" with lamp black.
Sealing the pixel layer.
Exposure and tray development.
I realise that there is quite a lot of modern literature on doing autochromes, but have decided to ignore these this time.
Would take to long to get all recommended materials.
PS. I have absolutey no problem with making a fool of myself!
Just in case it is not evident from the first postings, this will be something of a slow journey. So perhaps a check of how far I have got should be every couple of days or so!
I have been able to colour the starch.
The chosen dye colours are those that were available locally. I can always choose colours in images I will try and register, either tests or still life, which match the colors in the matrix on the autochrome. There is obviously a problem with red as X-ray film is a variety of ortho film, whilst the autochrome plates (and later films) did employ panchromatic emulsions.
The dyes are yellow/orange/green/vioilet - so some red is present.
The photos show the results of dyeing starch in an ethanol solution.
The first image is the result of filtering afetr first dyeing. The results are rather dark and with an even darker crust. Further cleaning with ethanol produced much cleaner colours which have exactly the feel as the original starch. I do have a small microscope ( amazing the things come in lens lots!) so I will try and capture some starch nodules tomorrow.
It is obvious I will have to do a series of experiment outside of the darkroom with:
- removal of emulsion on one side of the x-ray film.
- application of a clear glue that remains "sticky".
- dusting this glue with colour pixel mixture.
- removal of excess starch grains.
- flatening the glued grains. I have no idea how to do this yet!
- filling up colour voids with lampblack.
- sealing the coloured starch without dissolving the dyes out of the grains.
To-day, I took out a 24x30cm x-ray ( Fuji Medical Super RX ) to check the mechanics of placing the autochrome layer one side in full daylight.
This is a green two sided emulsion film. No notch system, and all 4 corners are rounded, however, it should be quite easy to feel/see the different sides after treatment.
I mounted a section of the film on a clean glass plate with ordinary paint masking tape. I used the method reccommended by X-ray users (after exposure) to remove the "back" exposure, that is, diluted domestic chlorine cleaner/bleacher. This worked extremely well - a gradual, rather than dramatic, removal. In fact the two layer structure (protection and colour/silver nitrate?) was very visible and the quite precise boundary can be seen in the image. l built up 4 tiny heaps of the dyed starch granules, spread the out with my finger tips and used a synethic spray lacquer.
Without the glue layer, the grains were spread a bit. But there was no colour seepage into the clear lacquer. The grain structure was much more apparent (microscope) after spraying.
Tomorrow, a mixing of colours, glueing, flattening and sealing.
I realise that I have to do a reversal of the negative as part of the development. I am a bit nervous about the chemistry involved in removing the silver after the first development - especialy in relation to not staining/oxidising the starch layer. Anyone have any genius ideas? Did Lumiere use reversal fil, perhaps?
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