The model you can see at the top is my favourite. It was inspired from the cover of the ultramarines limited edition artwork. Anyway, back to the tutorial.
I (unlike YoshKa) mostly use paints from the new range, as most of my old ones mysteriously dryer out. Therefore I will be using the new names, so if you have the old paints, don't forget to look at the citadel paint conversion chart to find a closely matching colour.
First off, undercoat the model with a Black Spray. (No picture but I think you can imagine it easily enough).
1. Undercoat the whole model with a Macragge Blue Spray (Painting the basecoat is also fine, but I find a spray coat is much nicer to work with).
2. Next apply a wash of Drakenhof Nightshade to the model. Don't worry about washing areas that won't be blue, it won't effect you painting over them later.
3. When the wash is dry - and it has to be completely dry - paint all the flat armour surfaces in Altdorf Guard Blue. Try not to get any paint in the recesses as that will ruin what the wash has done.
4. At this stage I hold off the blue highlight, in case any retouching needs to be done. Now paint in all the metal areas (gun, joints and vents, etc. - but not any gold) with Leadbelcher. Be careful as you apply this coat, not to paint over any of the blue armour as you will need to re-touch it. I can tell you that that is a pain to do.
5. The next base coat to go on is Khorne Red for the eyes. I personally paint the gun casing red instead of black, so paint that with Mephiston Red.
6. The areas such as the eagle chest plate, any skulls, the icon on the bolter and the should pad trims are all gold. So first I base coat them with Balthasar Gold. Then paint over all the Balthasar Gold in Gehnna's Gold.
7. Now for the rest of the washes. Wash any Leabelcher areas with Nuln Oil, and wash any Gehnna's Gold areas with Agrax Earthshade. Again be careful not to get any wash anywhere else.
8. Add some Evil Sunz Scarlet to the eye lenses and highlight the gun case with Evil Sunz Scarlet.
9. The last colour for the eyes is a nice orange. Troll Slayer orange goes in the tip of the eye nearest the nose.
10. Highlight the gold and metal areas with Runefang Steel. Make sure that the highlights applied to gold areas are very thin, as not to obliterate all the gold. Also paint the studs on the armour in Runefang Steel.
11. Now comes the final blue highlight, Calgar Blue. Highlight all the raised edges of the armour in Calgar Blue. This along with the first blue coat is probably one of the longest stages to do, but don't let that discourage you from this stage - it makes it look amazing.
12. Finally it's time for the magic. Glaze the blue armour with Guilliman Blue and the eyes and the bolted casing with Bloodletter.
13. Time to paint the purity seal. Paint the wax with Mephiston Red, wash it with Agrax Earthshade, then highlight with Wild Rider Red. Unfortunately at the moment I don't have the paints for the parchment, however I would recommend Zandri Dust, Seraphim Sepia, Ushabti Bone, Pallid Wych Flesh and then some writing in a black or brown of your choice.
14. To base the model I use Mournfang Brown as an basecoat.
15. Then I drybrush Balor Brown over that. Sometimes this can appear really bright so try not to over do it.
16. Finally I add another drybrush of Steel Legion Drab to tone down the Balor Brown, if it is too bright (although I do it even if it isn't too bright). At this stage you can also add in some transfers. Just coat the transfer area with 'Ardcoat then apply the transfer and seal with a coat of Lahmian Medium over the transfer.
17. Finally just fill in the edge of the base with Steel Legion Drab, and you're finished!
Have fun painting. Here are some completed shots.