Interesting stuff - what program have you used to create these? I use CorelDraw for mine, and print my own on a laser printer where possible, fortunately I haven't needed any white lettering for the project that I've been working on.
Here's one of the tanks - all of the decals on here have been home made:
[attachimg=1]
Below are some notes about some of the things I've discovered when brewing my own:
Free font sites:
http://www.fontyukle.org/en/
http://www.dafont.com/theme.php?cat=114 ... text=58134
There are many others.
What the font:
http://new.myfonts.com/WhatTheFont/
Is extremely useful if you have a good image of the text you want to create, as it'll tell you the closest match. It is a commercial site, so if you want one of the ones it highlights, you'll have to pay for it. Of course, there's nothing stopping you googling the name of the font in question...
It has its limitations though, for example it'll only read dark text on a light background and it struggles if the letters are quite close together.
If you can't get a good image, or you're looking at something that is light on dark, you'll have to trawl the font sites looking for something similar to what you require. It's time consuming, but ultimately rewarding when you find exactly what you're looking for, or something that's near as dammit
In terms of company logos, it's a bit more restricted, but there are a couple of sites about that have vector images of corporate logos:
http://www.brandsoftheworld.com/search/logo/shell
http://www.seeklogo.com/search.html?q=norsk+hydro
They're mostly North American logos, but not all. For example, the Total logo I've been using has come from the seeklogo site. These are downloaded as vector graphics, so can be opened up in your program and resized as necessary.
If you can't get the logo you need, as long as you can get a decent photo to work from, you can trace the outline and then fill in as necessary. The Railfreight Petroleum symbol was done this way, and as they're standard size, in theory I could draw the Coal or Distribution symbols from it, now I've got the proportions right. It's time consuming, and a total ballache, but it is ultimately satisfying when it looks like it's supposed to
I've done the Caib logos in the same way.
The other source of images for use, such as the hazard diamond on the Hazchem panel, is Google images. They won't be the best quality, but if you're scaling them down to fit on a 4mm scale wagon, then no-one will notice! In the example below, you can see that the Corrosive symbol is of much lower quality than the rest of the panel, but it won't show when reduced to model size. If you really wanted to, you could trace these as well, I decided that life was too short! No doubt vector versions can be purchased, but I expect these would be reasonably expensive.
[attachimg=3]
Hope that's of interest to someone.