Ruskin usually has in mind particularly Titian, Veronese, and Tintoretto when he refers to the Venetian - but he also refers in MP I:83 to the golden sky of Marco Basaiti.
Compare the reference to Titian sacrificing the truth of landscape to mere pitch of colour at MP I:146. At Works, 4.326 there is a reference to the 'golden light and deep-pitched hue of the school of Titian, whose virtue is the grandeur of earthly solemnity, not the glory of heavenly rejoicing'.
Perhaps Ruskin has in mind the comments by Reynolds on Bacchus and Ariadne in Discourse Eight, and the reference to 'that great effect which we observe in the works of the Venetian painters':
It ought, in my opinion, to be indispensably observed, that the masses of light in a picture be always of a warm mellow colour, yellow, red, or a yellowish-white. ( Reynolds, Discourses, p. 159)