What glass do you use? Effetre/Moretti, or something else?
Your question isn't quite as easy to answer as it used to be. Completely changing color in the flame is striking. If you use Effetre, you're probably familiar with transparent red and transparent yellow. The rods start out as sort of amber, and when you heat them they change to red or yellow. That's striking. I think transparent orange is a striker too. Rubino (gold pink, gold ruby) is sort of a striking color. Sometimes the rods you get are close to the ultimate color, and sometimes they're really pale and need to be struck to get the hot pink color. The opaque pinks are basically rubino mixed with white. Depending on the batch, sometimes you can get a darker pink out of them by striking. With the latest batch of the dark pink, which is so vivid that it looks almost like evil purple, it does seem to pay to strike. That's pretty much it for the basic Effetre line. In the hand-pulled colors, the question is more difficult, because some of the colors do weird stuff, and there starts to be a fine line between whether it's really striking to a different color and whether it's just, well, doing something weird. Tongue pink is definitely a striking color. Starts out white, strikes (if you're lucky) to a weird pinkish terra cotta shade. Powder pink, also striking. Purple #254 (evil purple), also striking, although it has the devitrifying quirk on top of the striking issue.
That's all I can think of at the moment. I never use silver pink or opal yellow, so I don't know about them. I think silver pink was supposed to produce some colors, although I think naked sacrifices to the moon goddess might have been required.
Some of the Effetre opalino colors are striking. Opalino pink (rosa) strikes at a really low temperature (cool). Opalino carnelian a/k/a copper strikes. Sometimes it's coppery, sometimes it's bubblegum.
For strictly STRIKING colors, you're using a neutral flame.
When you're pulling metallic effects out of glass, you're talking about one of two things: (1) reduction; or (2) silver plum. I don't know what the story with silver plum (dark and light) is, but it insists on having oxygen before it will cough up its iridescent hues. Everything else wants to be oxygen-deprived. Accept it, and don't insist on understanding it. (Or do. Just don't insist on me understanding it.) Silver plum is going to give you a duller metallic look with some oil slick iridescence. It kind of reminds me of pewter, but with some peacock-ness to it.
I'm not going to call making glass look metallic "striking," because it would confuse me. I'm going to call it "reducing," because that's almost always what it is. I'm going to forget about silver plum except when I'm forced to talk about silver plum, which I'm done doing for the time being. None of the reducing glass that looks good is Effetre (Moretti) or Vetrofond. Rubino does reduce, in the sense that it changes in a reducing flame, but it looks absolutely awful. It turns gray and cruddy and horrible. Until last year or so, all reduction glass was a COE other than 104, but now we have those lovely lovely glasses from R4 and Double Helix. We can still use the reducing glass that's 96-ish from Kugler and Reichenbach and probably somebody I'm forgetting.
If you want chrome-shiny, one of the COE 96 reduction glasses is what you want. (Silver plum won't get you that effect, and neither will one of the new heavy silver glasses.) It's finicky, and slight variations in flame chemistry and time in the flame will change the colors that you get. The exact same technique on a different torch will get you a different result. The colors in the names (silver blue, silver green, aqua blue silver, tobacco brown) refer more to the color of the base glass than to the color you'll get when you reduce them. Mostly they come out some shade of silvery, but the Kugler 215 tobacco brown that I use a lot comes out metallic blue if you reduce it right, and there's a rumor that Iris Gold will really reduce to gold, although I'm -- darned -- if I can do it yet. (I am, however, plugging away at it -- and will someone remind me whether it's the Reichenbach or the Kugler that's supposed to be more reliable at coming out gold?)
You need to do a little experimenting with reduction glass to see what works best for you and your torch. Your reduction needs to be the last thing that happens before the piece hits the kiln, because exposure to a neutral or oxidizing flame will erase the effect. It takes only a few seconds in the flame. Watch carefully, and as soon as it starts to look metallic, take the bead out and look at it. If you over-reduce, the glass will get muddy and dull. You can sometimes reverse the reduction by exposing the bead to a neutral or oxidizing flame, but the results seem to be better if you get it right the first time.
We're all still learning how to use the R4 and Double Helix glass.
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