Dark spots coming through my paint

Hi, I'm kind of new to painting with oil, this is only on my third painting with Geneva oil paint and I'm having a weird issue. Dark spots are appering! I started this painting yesterday and by last night I saw these dark spots coming up through my paint. Especially in the background. This piece is done on a generic 8oz Prime 8 x 10 canvas panel. I primed it with Geneva Foundation canvas stain two days before beginning this painting. The colors I am using are only titanium white and burnt Umber & French ultramarine to make black. If anyone knows what's wrong, please let me know. But the pictures not done so please don't judge. LOL


  • dencaldencal -
    edited December 2021

    Welcome to the DMP Forum.

    Possible causes:

    Poorly mixed paint. Mould. Contaminants. Support induced discolouration. Finger prints.

    Judging by the shape and location of the dark areas finger prints seem to be the problem.
    The chemistry of finger prints could cause weird adhesion/reaction effects with the pigment/medium constituents.

    When the painting has dried paint over the discoloured areas.

    These studies showed that the components of a fingerprint are 95-99% water and organic (protein, amino acids, urea, and lipids) and inorganic (sodium, potassium, chloride, and phosphate) compounds secreted from eccrine, apocrine, and sebaceous glands. ...
  • Thank you Denis! I was thinking it could be because I only used one layer of the foundation stain.?
  • The paint is too transparent. Geneva? Probably not mixed long enough on the tube. Mix well and repeat.
  • Thank you Kingston. Yes it's Geneva. 
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