I understand you can combine Vodka/lemon juice with color. Do you need it for the airbrush liquid colors, and is there a ratio when attempting this? I want to paint my tree brown instead of mixing it in the fondant if possible. Any help is appreciated!

I use airbrush color that is made specifically for airbrushing. I know other people mix colors to use in their airbrush, but I am too big of a chicken to do that... (too many nightmares of a hopelessly clogged airbrush.)
I do a lot of painting (I use gel color, or petal or pearl dust mixed with grain alcohol or vodka). but I wouldn't use lemon juice (did you mean lemon extract?) The reason that people use lemon extract is because it has the highest percentage of alcohol in it compared to other extracts.

When I mix up paint, I do it in very tiny batches - the alcohol evaporates very quickly, and I keep it relatively thick - like ranch salad dressing. If its not thick you will have problems with streaking. When I'm mixing paint with the dusts, I even use an eye dropper to add the alcohol, so I can precisely control the amount that I'm adding.

Thanks-that helps. However, you said you use the gel(as in Wilton????) If it is the wilton, and you keep it the consistancy of dressing.....do you go thru it pretty fast, or will it store? I'm the person who needs the "___FOR DUMMIES" outlines. If there is an area like that for me, let me know! I appreciate your reply greatly!

wow this is good info, I need to learn more about painting my fondant cakes
thanks

RE:
Gel color - I'm referring to what is sometimes referred to as paste color (Wilton).
You can mix Wilton (or homemade) piping gel (which is clear - its a mixture of corn syrup and gelatin, and maybe some other stuff???) with color, but it will be transparent unless you add white white color (or something with titanium dioxide) and I DON'T recommend painting with piping gel - its too lumpy.

Most often I use Americolor Gel Paste Food color - unlike the Wilton colors these come in squeeze bottles and its much less messy to add color - you don't need a toothpick or whatever you use to add Wilton color. Also the Americolor comes in a wider assortment of colors including Super Red and Super Black which make it easier to achieve really deep shades. I order Americolor online. It comes in 2 sizes and I usually just order the large size.

I can tell I need to get out of Wilton World and try some new things. Thanks again for your help!

If you're painting a TREE, it's not a big deal if there's some streaking, it just looks more like bark that way! Here's a tree I did a while back:

http://cakecentral.com/modules.php?name=gallery&file=displayimage&pid=1195142

I covered my cake with white cream cheese fondant, then painted with Wilton brown gel mixed with vodka. This paint was mixed really thin, but if I'd made it a BIT thicker (Though not quite ranch dressing...), it would show the brush lines better, and look more wood-like.

This was painted on peanut butter buttercream, but it gives you a little better idea:
http://cakecentral.com/modules.php?name=gallery&file=displayimage&pid=1298200