With Stellings Golden Brush round hog hair brushes for oil painting you get:

Has an interestingsurface quality

Pigment classification: Dioxazine special

Pigment Classification: MixedColor Index Name: N/A / PY150 / PR206Color Index Number: N/AChemical Description: Titanium Dioxide and Iron Oxide Coated Mica Particles / Nickel Complex Azo / QuinacridoneOpacity/Transparency: Semi-TransparentLightfastness Rating: N/APermanency: ExcellentMunsell Notation Listing: Hue N/ Value N/ Chroma N/AGloss Average: N/AViscosity Range: N/ACIE L*a*b* Values: N/ATint Strength: N/A

but this modern formula offers a classic deep blue that is permanent

old holland oliemaling old holland blue Hooker's Green Lake Light Extra With Stellings Golden Brush roundColour name: Old Holland Blue Colour number: 223 Series: C Pigment classification: Phthalocyanine Available: in 40 ml Colour index: PB15 Colour index number: 74160 Lightfastness: Lightfast pigment according to ASTM category 1 and 2 Opacity transparency: Opaque