While I am on the subject of dyes, I will mention That I am having very promissing results with chlorophyll as a red sensitizing dye. I buy "pre-washed" babby spinach in those celophane bags. I cut it up and soak it in 91% IPA IPA,ambient temperature, overnight. I then strain it without crushing. I get a bright green clear solution, about 1% solids. I chose the IPA because it is readily availible in my area and I do not see a need to go to another solvent. I am using about 500 mig of solids per mole of silver.