With the advent of Java 7 and jAlbum 10.10.2, it is now possible to use semi-transparent colors in page layouts. These work in all modern browsers - Firefox, Chrome, Safari, and IE9. In IE8, IE7, and IE6, traditional opaque colors must be specified. If only a semi-transparent color is specified, these older browsers will ignore the CSS, and display no color at all. Skin developers must make provision for this peculiarity if they wish to support IE8, IE7, and/or IE6.
These are not simply pale versions of the regular colors; they will, in fact, allow background colors or images to "shine through." Therefore, a semi-transparent red on a blue background will appear purple.
Skins must be modified to make use of semi-transparent colors. If a skin has not been so modified, and you specify a semi-transparent color in the user interface, the skin will ignore your choice, and use the corresponding opaque color, instead.
If a skin has been modified to allow the selection of semi-transparent colors, the user interface will look something like this:
The text field shows the hex value of the color. The traditional hex value for red, for example, is #ff0000. The new hex field has eight characters, rather than six. The first two indicate the degree of transparency, with 00 being completely transparent (invisible) and ff being completely opaque. A value of 40 would be roughly 75% transparent, a value of 80 would be 50% transparent, and a value of cc would be 25% transparent. So, a hex value of #80ff0000 would be a 50% transparent red.
The color swatch has been programmed to show a checkboard pattern if you have selected a semi-transparent color, and a solid color if you have selected an opaque color.
There are several other ways to specify a semi-transparent color. If you are running jAlbum on top of Java 7 (the Windows version of jAlbum is now bundled with Java 7), there is a new color selector. If you click on the color swatch and then choose the HSV or HSL tab, there is a "Transparency" slider with percentage values. Moving the slider to the right makes the color more transparent.
On the RGB and CMYK tabs, there is an "Alpha" slider with alpha channel values. This operates in the opposite sense; moving it to the left makes the color more transparent.
Oddly, the "Color Code" field on the RGB tab does not show the full eight-digit color code with the alpha channel value in it.
You can use any of these sliders to adjust the transparency of the color you've chosen. If you're not using Java 7, the only way to specify a semi-transparent color is to enter the eight-digit hex value.