The decal project continues. I bought some Inkpress Media white vinyl decal paper on Amazon; it was one of the lesser expensive ones (about 20 bucks for 20 sheets). If you decide to try doing this, you'll be glad you bought enough paper to screw up a few times. I have two different printers at home; a wireless inkjet HP3520 and an older inkjet HP5850, and it's a good thing I did. The vinyl sheets would not feed into the newer 3520 no matter how I set it up, and jammed every time. They fed with no problem on the older 5850. You'll have to experiment with the settings on your individual printers as far as print quality goes, but I found the best colors printed with the "best" setting on the 3520.
All the decals shown here were created with free shareware called Inkscape and Gimp (the Gimp was used just to create the silhouette of the Super Tenere on the "Ride the World" decal). I'm not a computer guy at all, but between the software, Google, and Youtube tutorials, I figured out enough in a pretty short amount of time to create these decals.
After printing the decals I clear coated them with about four light coats of Krylon UV Resistant Acrylic Overcoat, which I picked up at a Michael's craft store. That should waterproof the ink on the decals, and keep them from fading for a while. We'll see.
Obviously, there are limitations on printing decals this way. The colors aren't as deep and vibrant as they would be on a professionally made decal, for one thing, and the color palette is limited to what is available in Inkscape. The colors can end up either lighter or darker than you want, depending on the way it's absorbed by the vinyl. All in all though, it's a pretty cool way to make some personalized one-off helmet or bike decals. The software is free, the paper is about 20 bucks and the clear coat was $6.00, so it's a fairly cheap process. If you wanted to print something really simple, like a photo of your kid, you wouldn't need the Inkscape software; you could print a jpeg image right to the vinyl decal paper ( you could even do some limited effects on a jpeg using Microsoft Paint). The advantage to creating decals as .svg files is that you can create an original and then make it as large as you want, and you won't lose any definition.
As soon as I'm sure the overcoat has cured, I'll put some of the decals onto my helmet and see how they look.