So your work is hybrid afterall :] That's not a bad thing (if it makes your work better to you!), it's just not what PJ is about - PJ is about works created entirely using pixel art techniques. Not accepting hybrids is analogous to a graphite drawing gallery not accepting paintings - graphite may have been used to make the latter, and may even still be clearly visible, but the overall work isn't really a graphite drawing anymore, it's something else. Not something worse, just a work in a different medium, a medium that happens to not be what that particular gallery is about.
Noise is a "dirty" tool that generates new colours and pixels outside of your control, so it's not allowed here. Using hue/saturation tools is perfectly fine as long as you're careful with the resultant pixels and that you're not creating unwanted new clusters. PS is actually excellent for pixel art (I use it too), but it's important to be mindful of what you're editing and how. For example, applying a contrast or hue adjustment over the whole piece, or over all instances of some of the colours is fine, because it doesn't create new colours or noise (it essentially replaces the old ones). But, applying the same with a gradient clipping mask is not a great idea because the gradient causes a blending that creates a lot of colours outside of your direct control.
You can even use tools like noise and gradients in your work, as long as you clean up the result to the level of pixel/cluster-level control*. Pixel art can have noise and subtle colour variations, the difference is the level of control.
* Although I say this, in many cases it's actually faster to create these things by hand than it is to use dirty tools and then clean them up xP Noise especially.
Well I didn't expect such details, thanks for taking the time to enlighten me.
I agree I may have too many colors, the thing is that I learnt to make pixel art by myself on Photoshop, with layers and what not, so when I'm not happy with the colours, I can't help but give it a hue/saturation, or a colours balance. I also like to add a light noise effect on the final piece (I know this sounds like a bad idea), so that's why I have so many colours. But I didn't use any brush tool.
I didn't know the vision of the pixel art to PJ was so extreme, I just like to make nice pictures and I thought some pixel arts I made would fit in with all those amazing pieces I saw.
I guess I'll try to restrain myself with some 16 coulours palettes and practice. I'll be back, thanks again for your answer, eishiya.
I didn't comment based on whether I "liked" or "disliked" anything, I commented because this type of work is not accepted on PJ. Looks like I wasn't wrong, since it's been sent back for revision instead of being accepted.
The problem with this piece is that you have way more colours than you need. You've created a nice image here, and your overall colours look good. The problem is simply that while it's a good piece, it's not a good pixel art piece, because it displays no pixel-level control. Did you really pick all 600 (+1 transparency) of these colours yourself and place them exactly where they are, knowing exactly why you were choosing each colour and placing it? Because it looks like you chose the main colours and allowed your drawing program to add more colours as you blended them (for example, by using the brush tool). If you did choose and place them all by hand, then that's just poor colour economy, because most of those colours are so similar that they're indistinguishable. If you chose and placed each colour by hand, you would've saved a lot of time by reusing colours. And if you didn't, then this isn't pure pixel art.
Alternatively, maybe I've misunderstood entirely - did you perhaps pixel this work, and then resize it? That could've also created all those extra colours.
"Any art you post should be PIXEL ART! Pixel art implies that each pixel is placed by hand".
Don't worry, I can read the rules and I'm not making any kind of hybrid digital painting and pixel art. You're just making things up because you don't like the colours I chose. Your comment isn't constructive at all. Please, teach me how to make the "purest" pixel art, master :)
The shapes here are pixelled, but the colours within them show no control at all. This work has some pixel art sensibilities, but is ultimately a hybrid of pixel art and digital painting. PJ is for "pure" pixel art only.
I think I get it, no unwanted clusters or new coulours generated by tools unless you keep the same level of control on the whole piece by cleaning up.