I used turmeric for this one, with a five-day exposure:
It's very sensitive, and I think even a day or two of exposure would result in a good image.
For this one I used red wine again, with a ten-day exposure; it is rather dim and I think twenty days or even more would have been better:
The long exposure required may be a result of the process I used here. I printed the image from a computer, then applied cooking oil to its reverse side in order to make it transparent. Last time I tried this, the oil leaked through onto the red wine emulsion, making a big mess and virtually no image. So this time I covered the light-sensitive paper with a plastic transparency, put the oiled paper on top of that, and then put a glass plate on top of the whole setup. The glass and plastic may have cut down the amount of UV light, thus requiring a long exposure.
On the bottom right you can see a big blotch where some oil somehow leaked onto the paper despite the transparency; it quite thoroughly messes up the image.