Thursday, January 3, 2013

The Dreaded Pink Blush

Q: I did a couple of tests with Debitus silver stain on Waterglass and Spectrum clear vintage. You are right about 40% silver sulfide: It was the best. 20% sulfide was good to ( only for vintage ). Silver Chloride - poor results. But I still have a problem: on some samples I have some foggy light brown-reddish color that is impossible to remove in the areas where the stain is light. I don't know what could be (with Reusche in the past I did not have such problem).
I mixed the stains with sandalwood oil and little lavender oil and fired at 1050 F ( electric kiln ) - 500 F/hour, ramp hold -1 hour, off. I'm sending in attach a photo with 3 samples. Where the stain have a very light appearance - in reflective light I can see this brown-reddish foggy color Any idea what is wrong?

A: You are not alone in reporting this problem. I have experienced it myself with some stains. I do not know the exact cause. It may be related to the clay body firing onto the glass. A dilute solution of hydrofluoric acid would probably do the trick. Personally I have found it easier to switch to a different stain. I typically reach for Reusche 1383 as my go to stain these days. I find the gum in clay body is not as impossibly virulent as some of the other stains allowing me to even stipple the application with a scrub if I need to. Also I have not experienced the dreaded pink blush that you describe with this stain. If you do use hydrofluoric exercise the appropriate safe guards. If anyone reading this  can suggest another solution please speak up!

Question about Float Glass & Texture

Q: I will be contacting you in the next couple of weeks about scheduling the private class with you. In the meantime, I have another question. Is it OK to paint on regular float glass assuming that I will use enamels later on it or is that a no-no? If so, what do you do if you do not want any texture on the glass you are painting on. Artique works great, but the kind I have has A LOT of texture and I would rather use something flat. What do you think?
A: Float glass has a tin coating on one side that will affect silver stain and some enamel colors. You should always test float glass with a short wave ultraviolet light (sometimes marketed as a Tinscope or Tin-light). Mark the appropriate side of the glass for your use. Silver stain takes more intensely on the tin side of float glass. Enamels are another story. Sometimes interaction with the tin side is bad. I have had problems with some blue, green & turquoise enamels going grey or black. Other enamels, especially gold based colors – like pink, magenta, red & violet actually are more intense and saturated on the tin side - go figure! The answer, if you haven’t guessed it, is to test each color first.
Here is the link to the page on this blog that references UV light & Float Glass:

As far as texture goes, that’s a subjective call. Personally, I paint on mouth-blown Lambert's or Desag (which is similar to Artique). I prefer the texture of these glasses. If I’m painting a face I would avoid a mouth blown glass with a lot of seeds and choose something smoother but surface striations are OK by me – that’s what we’re paying the extra money for after all! If you really find the Artique texture objectionable you can always flip it over – the back side is considerably smoother.
Happy painting!