This is interesting, but not interesting enough. Not yet. You need to work further on your branding. What KIND of promotion for artists & designers? How is what you do DIFFERENT from anything else? What do artists & designers GET from you that they don't get anywhere else?
Your target market are social creatures. Are there withdrawn, shy artists? Of course. But most either want to meet other people, or are aware they must meet new people to promote their work. So some kind of party is what I recommend. Start thinking about how you can accomplish this virtually, online. A red carpet event, a premier event, a good old-fashioned mixer. It cannot be just about you; somehow, you have to build in a way for the participants to mingle and do what you say your brand allows them to do: promote their work.
Facebook ads can help you attract the right people. The question is, what are you attracting them to; why should they be in the room?
Where do artists and designers hang out? Online and offline? Where can you get in front of them that they already congregate at?
Your brand needs a shot of panache and a big reason for artists & designers to be attracted to it. The ability to promote their stuff is great, but they have to see for themselves how it affects them personally. That's how to get their involvement. And you want them talking about it--before you have this event. Get them to build the buzz, because they will do a much bigger and better job about it than you can.
In fact, go out and find celebrity spokespeople to shoot quick videos about why they're supporting your brand. What they're getting out of it. These don't have to be world-striding celebs: local will do. But begin. You can build on these. Show user adoption. Excitement from the target market. Narrow down on their reason for being in the room.
When it comes to building brand awareness there's absolutely no better tool than Facebook. It's the only tool that offers such laser-precise targeting, from age, gender, location, to workplace, industries, interests and bahaviours - and that is truly necessary for making the most of a small advertising budget.
Your goal, however, shouldn't be just raising brand awareness but achieving specific goals: if you want to generate leads, send people to your website and use a lead magnet to make them sign up or create a custom tab for the same, if you want to build a community, use Facebook ads to promote *offline* events and start building the audience there - it's crucial for you to identify those potential brand ambassadors and engage them as much as possible at the start, so that they become the advocates for your startup and help you to expand the community. If the startup is purely online based however, you'll need to identify those wow factors and put in place techniques that could increase the word of mouth and social sharing for the site.
An alternative that I could think of, is finding a site that's already established in that area and agreeing with them on a CPM model advertising. It can be effective sometimes, but you wouldn't know exactly the target audience you're reaching. So I would definitely go with Facebook!
I hope that helps, and if you'd like to have a chat on how to use the most out of Facebook advertising (target audience selection, ad campaigns split-testing and optimasation, lead generation, remarketing, etc), feel free to get in touch - I've been specialising in Facebook advertising for the past few years and I'm confident I'd be able to assist you.
If you're promoting artists and designers and want them to flock to you, then start by promoting an interesting artist or designer. Showcase his or her work and publicize it where other artists / designers will see it. Simultaneously invite your audience to join. The others will gravitate to wherever they see work like theirs being promoted.
Guess what I'm saying is ... Don't promote your abstract brand for promoting artists! Instead promote artists!