A pigment with two natures- and two lightfastness readings to match. Aside from the lightfastness confusion there are also health warnings so see those below. This warm orange-yellow is a very tricky pigment with two varieties which fly under the same pigment code. The problem is that the two distinct kinds of PY83 vary a lot in lightfastness.
In regard to PY83's lightfastness issues, we're grateful to Golden for illuminating the differences. One kind of PY83 has excellent lightfastness and is more opaque (the HR70 version), while the other form is transparent and has poor lightfastness. Unfortunately the current ASTM only ascribes one lightfastness code, which is applied by paintmakers in a blanket sort of way. So, the fading transparent version of PY83 is frequently mis-ascribed an excellent lightfastness rating, which truly only belongs to the other kind of PY83. The transparent, fugitive version has a lovely look to it, but terrible lightfastness. In the case of Golden, who made this discovery, they opted to keep the transparent version in their blends and adjust the low lightfastness rating to match. They shared a discussion of this as well as an illustration of how the transparent version compares to other pigments in the same color space.
In terms of health and safety, we were shocked to hear this is a problematic pigment due to benzidine (we advise all artists to research toxicity and benzidine in their pigments). This pigment metabolizes to a carcinogen-- Monona Rossol alerted us to this in her writing, more of her materials can be found here. It sounds like heating also creates a carcinogen. Additionally, contamination with PCBs is likely as well. There are also thresholds for limiting the dust so please consult proper handling.
Unfortunately, regarding the lightfastness confusion, it is hard to tell at a glance which of the two versions may be in any given tube of PY83. One hint may be to look at single pigment paints marked PY83 and assess whether the paintmaker lists them as transparent or very transparent. If so, they may be the fugitive kind, regardless of the lightfastness reading given by the manufacturer.
