Please help with tintable skin

Can someone please tell me how to make a skin template tintable, so that i can use make up edit in appearance. Is it done using alpha, this is driving me insane

I have not done this (yet) but I would imagine you need to fill your alpha channel with perhaps 50% grey, other than the area that contains the eyelashes. It may require a different shade of grey, but that is where I would start. I'm sure someone else will come along that knows more about this .

To make a skin that's fully compatible with the appearance sliders you'll want to carefully study all the TGA files in the character folder of your SL install. Those are what get combined to create default skins. You can replace them with your own custom versions. That's not a good method for making skins you intend to sell, however, since you'd have to sell the raw textures with full permissions so people can install them on their computer. The only other way to do what you want is to create a skin using the tattoo slots and make it transparent in the places you want the slider adjustments to show through. That has pretty serious drawbacks too since getting a good blend between your custom tattoo textures and the underlying default skin textures is very difficult.

50% transparency is way too much for a tintable skin. Instead, 15%-25% transparency is going to get much better results. The skin pigmentation and detail should come mostly from the skin texture. The pigmentation/rainbow sliders in the client should only be used to fine tune a particular pigmentation, not define the pigmentation. You'll lose detail if the skin is too transparent.

If you're going to mess with the makeup sliders and skin details, such as freckles, it's better to do what Chip suggests and make client side skin textures to replace the color layer TGA files in the client character folder. That way you get the full effect in a overlay. If you're creating skins for yourself, this is the only way to do it IMHO. The flexibility is second to none with freedom to add tattoo overlays in the texture boxes inside SL.

Don't bother selling skins this way (even with a license agreement). It may have worked (somewhat) about 2-3 years ago, but not now. There are far too many people involved in SL now that have no hesitancy when it comes to ignoring copyrights and license agreements simply because it's too easy and too tempting to do so behind the protection of complete anonymity.