Einion -- I posted some examples included in the recent thread on Oil: http://www.wetcanvas.com/forums/showthread.php?t=548950
The photos on this above thread are for the most part from my Photobucket inventory of the past year or two, with a new one on Yellow Ochre Natural and Synthetic comparison.
Of the Naples Yellow PY41 and "Naples Yellow" imitation PBr24 there is quite a bit of difference. I really as sorry that PRr24 has become labeled as a "hue" because it is an outstanding stand-alone single pigment, with only a similarity to the real thing, but not really a imitation in intent.
I have both Harding types of the genuine stuff, the Light and Dark. I also have Vasari's Naples genuine, as well as their two versions of PBr24: Naples Orange and Tuscan Yellow, as well as
their Naples Yellow (hue).
The Vasari are not shown except one PBr24 in a photo further down.
I have recently received small sample tubes, courtesy of Jacques Blockx, of Blockx version of four of their special and extremely expensive Historical Paints, including the Light and Dark versions. Also included by Jacques were the other two Historical Paints: Vermilion and Lapis Lazuli. (Yes, the Light version is slightly greenish! Very unusual!)
Here is a color sheet showing the Blockx colors, in various intermixing, along wtih comparison to the Harding genuine Naples, and other similar colors. (apologies --the red in the Vermilions is slightly oversaturated in the photo)
I don't like to do redundant posts between the various forums here at WC, but this example of some PBr24 will be convenient to contrast to the genuine Naples above.
In opacity, all the genuine Naples I have tried are to be considered semi-opaque: they are opaque, but their tinting strength is not very powerful. Vasari is the most opaque, most powerful and also a bright yellow. The Harding Light version has the most vibrant bright yellow -- similar to an anemic version of Cadmium Yellow Light. The very lack of opacity and strength is a plus, for the uses geniune Naples will most commonly be put to -- portraiture, and secondarily, landscape painting.
In consistency/handling, Vasari is the thickest, but not pasty. All the genuine Naples have the consistency range of its primary components lead and antimony, being most similar in handling to lead white paint -- in other words, quite smooth and creamy.
The PBr24 paints have a tremendous covering power, being very opaque and very strong tinters. Quite similar to what you might imagine a "cadmium earth" would be like. They have a some variation in hue, the most extreme probably being the Vasari Naples Orange and Tuscan Yellow, hence the brand's desire to provide both. PBr24 is fairly close to the Dark versions of genuine Naples, but lacks its subtley and transluscency. A very useful pigment, that I dare say I've used more often than genuine Naples -- which I have a natural aversion to using up!
The following sheet shows my comparisons at the time I had received the Vasari Naples, along with their Capucine Red Light and their new (last year's introduction) of Transparent Oxides --the five colors center-left of the sheet.
To the right of the Vasari Naples is Harding's Light verson for direct comparison. The Harding is the brightest of the Naples I have tried with the strongest chroma.
Down the left, center and right sides are various mixes. The left side shows how UMB mixes into the five Vasari colors shown. The central (yellow) column, shows Vasari Naples mixed into the four other Vasari earth colors. On the right side are two similar columns showing the five Vasari colors mixed into Venetian Red in the left-hand column, and Capucine Red Deep on the right-hand side.