Hi Stephan,
Thought I should visit your WIP after all your supportive comment on mine
Your orc face looks awesome, if you're specifically asking for advice on how to make that face more vibrant I'd say 'No need' especially if you've got 35 lined up and are a self confessed impatient bastard (though anyone taking on batch painting of 35 minis either has plenty of patience... or will have by the time they finish). Buddhist teaching states 'We should love our enemy for giving us the opportunity to practice patience' . Based on that you could end up really loving your orcs! (but if it goes beyong platonic we just don't want to know!!).
Black base versus white base versus coloured base?... Each will have minimal impact under undiluted paint but start having more impact if you dilute subsequent coats (impact increases as dilution increases). White should be more vibrant under thinner coats as it reflects back more light, but can get muddy if you over paint in different colours (if the separate colours would give a tertairy colour, the same happens to the light travelling through the coats and reflecting back from the white base). Black can give a dark and moody look so great for minis with lots of shadowy areas or where you want a sombre brooding effect, can be a beast trying to lift highlights back up up with glazes though. Coloured bases rock if your minis have a dominant colour... if you're batch painting stupid-many Space Marines in McCragg Blue the matching GW rattle can just makes sense.
Shading up or shading down? I'd say either and/or both. Darkening shadows or lightening highlights will both increase contrast, if you use thin glazes on either or both you can fine tune to the result you want. That said, if your initial coats are round about where you want to end up it can save hours tweaking with glazes. I tend to rough in the general colours shades and highlights without too much care (within reason, slapping on thinned coats shouldn't cause blobs or obscure surface detail) to get the basic balance and then progressively refine from there (same process I'm applying on Tony the Acid Trip Pony's wings). Also means minimal time lost if you sketch it in only to find it truly sucks (always assuming you have enough easthetic sense to recognise 'so wrong!'... and you know why I'm mocking myself here!).
And on that note, it's high time I put down keyboard and lifted brush... all the best mate!!
I also really like your Crypt Ghoul greenstuff work, it really portrays nightmare horror. I painted the same set some years back but they're quite sterile and soulless compared to yours!
