Anne, let me share my experience, which in some ways agrees with the Happiness Farms info, and in other respects differs.
First of all, my early Caladium crosses were done using the Happiness Farms info. It worked, but wasn't completely guaranteed because of the difficulty in determining when the bloom was 2 or 3 days from opening. Then I found out what I'm going to share below.
You don't really have to guess about when the female flowers are receptive because when the bloom first cracks open, that evening is the ideal time. I describe the day preceding the evening as the time when the bloom has "poofed"; that is, the spathe has lightened in color and has appeared to swell or inflate, almost cracking open at the spathe overlap (front of bloom). So you see the bloom poofed in the daytime - check that evening around 8 or 9 pm and the bloom should be completely open AND FRAGRANT. Yes, Caladium blooms do have a fragrance, contrary to what some information on the net may indicate. They are fragrant for only a short time but that's all the time you need to do the pollinating. This IS the ideal time to pollinate your Caladium bloom. If you miss it, the next morning is definitely too late. So if you do the deed a day or two too early, you are fine, but a little late and you are out of the game.
This is also the time when blooms you may have missed for female anthesis are reaching male anthesis (pollen shed). If you are fortunate enough to have a bloom shedding new pollen on the same evening as your chosen bloom is female-receptive (female anthesis), you can do the deed right then and there.
I have never failed to set berries/seed when using the above information. However, your fun is just beginning because once you are successful, about a month after pollinating, white berries will ripen. If you are not on it, ants will steal every one of them and your work will be lost! The seeds within the berries are about the size of a pinhead and they germinate quickly after cleaning and planting.
Above is a shot of nearly ripe Caladium berries. After they started forming, I secured them with a little sock made from old panty hose - I opened it for the picture. You need to sock them if you don't want to lose your work to the ants.
