Imagick - how to save PSD layer to PNG with alpha channel?

Question

PHP

I parse the PSD file and save some layer as PNG. I need to save the alpha channel with the transparency of the layer. How to do it? Tried setImageAlphaChannel with imagick::COLOR_OPACITY and imagick::COLOR_ALPHA constants - didn't help.
Well, after this question: when converting PSD to PNG, Imagick incorrectly converts layers for some layers, changes the colors of text and shapes, and quite strongly - in the layout the shape is yellow, after converting Imagick - blue-green. Can this be fixed? It is important for me to keep all the colors exactly as they were in the layout, but all sorts of complex layer effects can be omitted (except for filling with color).

Answer 1

The problem on both questions was $outputImage->flattenimages();
Once I removed it, everything was ok.