This is a quick summary of how to create an anthotype - I suggest spinach as a first attempt as it is relatively quick to expose - typically 4-6 hours in bright sunshine rather than several weeks for many other plants.
1) Working under normal room light and out of direct sublight, put a large handful of spinach leaves in a morter and pestle and add a bit of water (I find about about 7.5ml per handful works). If you don't have a morter and pestle you can improvise (eg spoon and a bowl) or use a small blender.
2) Grind the leaves to an emulsion
3) Strain through a muslin bag (or you could use a sieve or coffee filter) into a pot eg a yoghurt pot .
4) Paint a thin layer of the filtered emulsion onto a piece of watercolour paper - here I'm using Canson XL Aquarelle but similar papers work equally well. Repeat leaving about half an hour between coats to allow the paper to dry. I usually apply 3 or 4 coats.
5) Place the coated paper(s) onto a piece ply or hardboard - here I'm using the backing board from an old clip frame. To make a photogram* place a selection of items (not too thick) onto the paper, leaves or grasses work well. Petals can work but they need to be able to block the light eg I found poppy leaves do not block the light enough to leave an image.
Cover with glass and apply spring clamps or the clips from the clip frame. If working with children you can buy clip frames with perspex glazing. Just make sure that the glass or perspex does not have a special coating to block out UV light (cheap clip frames don't).
* a photogram is a photographic image created without a camera by placing objects directly onto the surface of light-sensitive material
6) Place in full sun on a day when rain is not forecast and leave for 4-6 hours - a bit longer if its cloudy. The process works because the sun bleaches the areas of the paper where the emulsion is not covered.
7) Remove your artwork and hopefully admire - experiment until you get a result you like. You can see on this image the grass on the right was rather fine and didn't leave a strong impression.
If kept out of sunlight eg in normal room light your anthotype should last for at least a few weeks. Photograph it with your camera/phone or scan it so you have a permanent record.
If you want to create a photograph rather than a photogram you will need to print your photograph onto clear acetate - anthotypes normally require a positive image so print your photo as it is (most photographic processes require a negative) and place that over the dried coated paper in step 5.
This is my bluebell image with the printed side of the acetate facing you. I have reversed image horizontally so that when I turn the image over, so that the printed side faces the emulsion, it is the right way round. Your image doesn't need to be in black and white but it is easier to visualise the finished result and it does need to be contrasty enough so that the dark bits on the acetate block out the UV light.
For more information I would suggest the alternative photography website here or if you prefer a book Malin Fabbri's book ISBN 13: 9781466261006.
