Color: Good. Crazing: Bad. Liner glaze: Good.

Color like this has become so trendy that multiple problems associated with it are being ignored by potters and hobbyists at cone 6. First, crazing (this network of fine cracks): People use dense burning bodies, ware doesn't leak, so it is deemed to be OK. When ware is made using stoneware clays having higher porosities, and it leaks, the clay bodies are blamed. And poor strength is also blamed on the clay. However, this potter has done two right things:
1. Using an iron-stained honey glaze on the inside (e.g. GA6-B). It does not, cannot, leach heavy metals. Many are mistrusting the ASTM D-4236 label on glaze jars and using intense heavy metal commercial colored glaze on food surfaces!
2. The honey glaze does not craze so the mug does not leak even though the body has a higher porosity than the supposed vitrification magic number of <0.5%.
The bottom line: Use glazes that don't craze, DIY ones if necessary, don't use really bright colors on food surfaces.

Links

URLs	https://www.astm.org/d4236-94r21.html ASTM D-4236 - Standard Practice for Labeling Art Materials for Chronic Health Hazards - It is not what you think! A standard that "applies exclusively to art materials packaged in sizes intended for individual users of any age or those participating in a small group". It "concerns those chronic health hazards known to be associated with a product or product component(s) when it is present in a physical form, volume, or concentration that in the opinion of a toxicologist has the potential to produce a chronic adverse health effect". The word "toxicity" is not mentioned on the page nor any methods for determining such. Furthermore, the labelling refers to hazards to which the potter is exposed in applying the glaze to the ware, long term, in small hobby quantities. IT DOES NOT ADDRESS leaching hazards the ware presents to users of the pottery. Even then, the standard states that "it is the RESPONSIBILITY OF THE USER ... to establish appropriate safety, health, and environmental practices ... based upon knowledge that exists in the scientific and medical communities". It also admits that "since knowledge about chronic health hazards is incomplete and warnings cannot cover all uses of any product, it is not possible for precautionary labelling to ensure completely safe use of an art product." It is interesting that one manufacturer displays this warning on pages relating to dipping glazes and accessory products (which are used by manufacturers): "Safety Warning: Tableware producers must test all finished ware to establish dinnerware status, due to possible variations in firing temperature and contamination." This warning does not appear on brushing glazes, even the reactive metal-saturated ones that potters and hobbyists use!

URLs

https://www.astm.org/d4236-94r21.html
ASTM D-4236 - Standard Practice for Labeling Art Materials for Chronic Health Hazards - It is not what you think!
A standard that "applies exclusively to art materials packaged in sizes intended for individual users of any age or those participating in a small group". It "concerns those chronic health hazards known to be associated with a product or product component(s) when it is present in a physical form, volume, or concentration that in the opinion of a toxicologist has the potential to produce a chronic adverse health effect". The word "toxicity" is not mentioned on the page nor any methods for determining such. Furthermore, the labelling refers to hazards to which the potter is exposed in applying the glaze to the ware, long term, in small hobby quantities. IT DOES NOT ADDRESS leaching hazards the ware presents to users of the pottery. Even then, the standard states that "it is the RESPONSIBILITY OF THE USER ... to establish appropriate safety, health, and environmental practices ... based upon knowledge that exists in the scientific and medical communities". It also admits that "since knowledge about chronic health hazards is incomplete and warnings cannot cover all uses of any product, it is not possible for precautionary labelling to ensure completely safe use of an art product." It is interesting that one manufacturer displays this warning on pages relating to dipping glazes and accessory products (which are used by manufacturers): "Safety Warning: Tableware producers must test all finished ware to establish dinnerware status, due to possible variations in firing temperature and contamination." This warning does not appear on brushing glazes, even the reactive metal-saturated ones that potters and hobbyists use!

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