Hi all!
Almost two weeks ago I got my new H2C and started to make multicolor prints. And sometimes I face next issue: some colors are “bleeding”. I can’t understand how it’s even possible, such as it uses different nozzles for different colors. I posted some photos below
Does anyone know how to avoid this?
Are you purging to infill?
I’ve noticed that with that setting on the H2C seems to not swap to whatever colour is used for infill in that area, just whatever happens to be loaded. So for example if you have black and red like for the tail there it might use black for the infill then do only the required walls in red rather than black infill in black areas and red infill in red areas.
You might be looking through the light-transmissive exterior layer of yellow and seeing more opaque inner layers of grey. Slice that again, and go to your preview tab, and inspect UNDER those elements to see if the slicer is making that area gray
Colour sequence
Sometimes the solution is as easy as changing the order colours are printed.
Flushing volumes
You can also increase the flushing volumes between the colours that have the issue. This will purge more filament between changes. It increases waste, but if the problem is this transition, it will reduce or remove it.
Testing
Confirm results by printing a slice of the model where you experienced the issues.
Slice and print your test slice.
You’re seeing a darker color showing through a lighter color. It’s not bleeding like ink. If you were using CMYK filament for a Lithophane, this would be how you’d combine layers to get all the different colors you need. If you look at the slicer, I bet you see grey in that area just below the yellow top layer.
I break my multi color prints up in to separate objects for each color, so I just assign a filament to each object after loading, no painting required. Doing it this way gives you ultimate control over what colors get used where. When painting however, this is really hard to control.
Seems here is a problem.
I just checked printed models and there are underlaying layers with another color
Is it slicer’s choice to slice model by that way? And is there a way to fix this?
UPD: Purging to infill option is disabled for both models
The slicer is doing what it is told.
If the model is built up in parts merged to a single model in the slicer, you can choose to set a filament colour to each part appropriate for your choices.
If the model is a single part, then it appears you (or someone else) painted it in the slicer.
If you use the paint tool, it can do a great job if you know how to use each tool correctly. Most can’t. The paint goes beyond the surface to give it enough saturation to be seen when printed. However, depending on the triangles and the resolution you paint, it can grab more than you expect.
Yes, as I wrote, I’m using printer for less than 2 weeks and I’m sure that I don’t know many things)
It’s not my model, it was downloaded from Makerworld. I tried to change some settings in slicer, tried to adjust Top/Bottom paint penetration layers options, but it does not change anything
I just don’t understand next thing
Here is layer #9
And here is layer #10
Why? If this part of model should be completely red? Next layers (12, 13) became red again
Every model is made up of many triangles, I designed some with well over 30 million triangles.
When someone paints the model to give it colour, they choose how many triangles (the resolution) brushes will affect. Too few and it takes ages, too many and you loose accuracy. Worse, the painting tool thinks many unrelated (to your eyes) parts get grouped in.
Have you looked at the paint tool yourself in Bambu Studio?
It is worth the time you invest in it as you can fix many of these issues with patience. Play with the different toolbar tools and the bar that changes the scale of the painting area (what I call resolution).
Don’t worry about being new. We all were, people move at different speeds and in different parts, so we can’t guess your knowledge level.
The fact you have this printer for two weeks tells people nothing about your experience level or if this is your first printer.
Pace yourself, expect to do trial and error. 3D printers and the world we live in is getting close to appliance level simplicity think microwave oven), but we are not there yet. We still have to learn lots.
The slicer is creating “Anchors” to ensure a good mechanical bond between different colors. Otherwise, especially small colored spots can literally drop out (amhik 
). As mentioned by @Bullocks and @RocketSled , this can lead to such bleed through effects.
The best way to avoid this is to have one object per color or to use modifiers for color application but this is not always possible.
As @MalcTheOracle suggested, there are further options to experiment with.
When I struggled with my first figurine paint and print, it took me at least half a dozen tries to get to grips with it. In the end, I locally used the sphere tool to apply paint also in depth. It was very tedious (especially when painting cavities), but, finally, I got there.
And just for the record, it took me a lot (!) longer than 2 weeks to attempt that kind of print. Respect! Keep going. You are doing great 
