Reduction tips for color

[Glenn Randle]

I have been playing with the "silver" colors from Kugler, 103, 105, & 107 trying to reduce them and having mixed results. I've just been using frit and mainly it's been applied touching white (61) or cobalt (41), or cased in clear alone.

Usually when touching white it turns tan, which isn't all bad but not really "special".

The silver green seems pretty applied touching the cobalt, but the silver blue didn't. Maybe I reduced the silver blue too much, since it turned tan around the edges.

I know nobody's going share their biggest docorative secrets here, but a few basic tips about reduction would sure be helpful.:)

Also, what are some other good colors to try? I have Gold Topaz (19) and A Gold Ruby (231). Are they good ones to try reducing, or does it make them uglier? Do reducing colors tend to show up better over certain other colors? And do they work well in powder form? Etc.?

thanks,
Glenn

[Randy Kaltenbach]

One thing that I have found with many reducing powders and frits (mostly Reichenbach) is that "less is more". That is, I often get best reduction when I use less dense colour layers.

Something you might try, is to actually use the weird reactions between colours in some sort of pattern. That can make the "not that bad" into "special".

One problem that I have had is that I've never been able to successfully case a reduced colour without losing the reduction :(

[Dave Bross]

The oxygen content of the casing glass re-oxidises the reduction. You would need a "reduced" clear to case it with.

I think there's a recipe somewhere in the archives that Pete posted way back. It's basically a clear done without oxidisers and a bit of black tin in it to maintain or actually cause reduction in the metal bearing colors. I would imagine that the amount of black tin would determine the degree of reduction.

[Eben Horton]

Originally posted by Glenn Randle


Also, what are some other good colors to try? I have Gold Topaz (19) and A Gold Ruby (231). Are they good ones to try reducing,
thanks,
Glenn


no...


i like to play with reducing colors as well and have found that the tempature of the glass makes a big difference hotter color will reduce differently than colder color-

experement experement experement ;)

[Glenn Randle]

Maybe I'm incorrect about my idea of reduction.

Colors which turn metalic (like chrome looking) under a reducing flame have "reduced", correct?

Well, that's not what I'm looking for. I want the "halo effect" which sometimes they'll do when cased. I think I've seen it done without touching another reactive color, but it seems easier to get an effect when the color which reduces is touching a certain other color.

Josh Simpson's work come to mind, the blue he's famous for. But, I think I've seen 3-4 other primary colors made to glow/halo also by other glassblowers. I recall ruby, gold, blue, maybe purple or green which were used.

Does anyone know what I'm thinking of? And better yet, able to describe how to achieve it?

[Pete VanderLaan]

Josh's work relies on a silver application on top of a glass body that has had local reducing agents added to it. You can make a reduction clear although almost all clear glasses are oxidizing in nature. A reducing glass allows silver to flow easily on the surface as opposed to an oxidizing glass where it tends to bead up. I am not comfortable describing what Josh does beyond that.

In a glass like a copper ruby, a colloidal suspension is forming which is a big name for a long stringey molecule. When things are transparant, the sizes of the molecules are small and light tends to be transmitted thru them. When they are big, light tends to be reflected off, creating the livery effect. Heat exposure changes the size of things. This is largely the case with silver colloids as well at least that's what I think. I also think too much lead in the glass is not your friend.

[Glenn Randle]

Pete,
What's the term for the effect I'm seeing when laying these silver colors onto white and a tan coloration forms?

Also, what's it called when certain colors form a dark outline along their edges. Kugler's Tobacco comes to mind, but others do it too.

thanks,
Glenn

[Ken Peterson]

powders work best on the surface. k-218 iris gold, and k-? gold brown are the most intense manufactured silver colors I've found. If you want halos around a certain color trail, apply a coat of copper ruby powder or frit before appying.

[Pete VanderLaan]

I believe that the outline is lead. I see it in my dense black when overlaid on a fluorine background that contains selenium, which is utterly intolerant of lead in any concentration.