CMYK color separation - WarmGlass.com

CMYK color separation

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Risa
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CMYK color separation

Postby Risa » Wed Jul 03, 2013 3:54 pm

I am thinking about taking a photo image, separating it into its color components and screen printing each color, then stacking and fusing back together. Anyone done this? What learning can you share? What color BE powders would you recommend?

I suspect this will be a long development process, but I have nothing but time this summer. Thanks.

Valerie Adams
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Re: CMYK color separation

Postby Valerie Adams » Wed Jul 03, 2013 6:33 pm

Are you planning to use enamels? If you can find the right colors, I don't see why it wouldn't work. I've done some fairly tight registration with screen printing.

GuyKass
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Re: CMYK color separation

Postby GuyKass » Thu Jul 04, 2013 3:33 pm

Just keep in mind that offset printing inks (at least when printing process) are transparent.

Ralph
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Re: CMYK color separation

Postby Ralph » Fri Jul 05, 2013 3:08 am

Charlie Cummings (Florida) silkscreens process (separated) photo images on porcelain. He has a detailed article in Ceramics Technical issue 35. You may be able to access an online version through Zinio. Note: Charlie's process is offset printing to clay via an intermediary plaster slab. This wouldn't be necessary for glass - you could print directly to a glass surface - quite stable. Printing to glass would present fewer problems than clay because suitable CMYK colors already exist for printing commercial decals.

Charlie's process yields a different quality to normal ceramic decals - the colors are embedded into the porcelain body rather than sitting on the surface of a glaze, and are fired to high ceramic temps - and maybe subject to further ceramic effects.

There's a likely possibility that printing CMYK direct to glass will look little different to glass decals - unless you found some way to further manipulate the images. (Edit: OK, just re-read your original post...you're intending to stack the separations! - great possibilities and your registration can be fixed post-printing)

Charlie's work is pioneering without doubt, and considerably more difficult than CMYK on glass. One of his final thoughts from the article: "Printing photographic images on clay is technically challenging and requires development of skills in multiple disciplines...While technology alone does not lead to making art, I have found it to be an empowering tool for doing something I had previously thought impossible..."

Don Burt
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Re: CMYK color separation

Postby Don Burt » Fri Jul 05, 2013 7:48 am

If you're using photoshop I think you'd have more fun creating custom alpha channels from selections within 'posterized' images and screen printing them, or better yet, painting them by hand or stencil sifting. Process color such as you're suggesting is kind of fussy (see Guy Kass' post about transparency), and it sounds like you're thinking of printing the components on separate layers. I don't envision that being as interesting as compared to being more deliberate with solid color fields like on a poster. Part of the reason I'm negative about it is that process color printing is kind of a magical thing in itself with rich alchemy of halftones, screen patterns and ink characteristics. At its best, its cool. It wouldn't de-suckitize it if was done badly, just because it was done with glass. I'm re-reading my post now and feeling bad about pooh poohing someone's desire to experiment. There's something disappointing about misapplied technology in tha name of art. I'm going to hit submit.

Bert Weiss
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Re: CMYK color separation

Postby Bert Weiss » Fri Jul 05, 2013 8:46 am

The trick is to try stuff and follow your eye to get you to a process you like the look of.

Ferro and Johnson Matthey both make CMYK vitreous color systems, used in printing. I am not sure, but I bet the magenta is a gold based formula. For fusing, you want to find a system designed for printing on ceramics as they use the fusion temperature range. Their glass systems are designed for 600ºC You will also have to add a background layer of white.
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Barry Kaiser
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Re: CMYK color separation

Postby Barry Kaiser » Fri Jul 05, 2013 10:34 am

Several comments on screen printing.
First, to simplify what was said before, screen printing is an additive process. Unless you are using transparent colors (with which I have no experience), you cannot create multiple colors by separating and then combining.
However, here is a trick that we use a lot. Brush paint the screen with different colors, then pull the final color on the screen. Whatever color went on first is what will show. You have to be very careful with the quantity of ink brushed on or you will get smearing of colors.
Here are some examples.
pendant1332.jpg
Grumpy 4
pendant1094.jpg
Fall Colors w/tree
pendant1441.jpg
Mt. Baker-night

Valerie Adams
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Re: CMYK color separation

Postby Valerie Adams » Fri Jul 05, 2013 11:29 am

The reason I asked if you plan to use enamels is because they're denser in color. One of the big topics during the 'what color do you want' segment at BECon in June was "we want magenta!". Even though you may be able to use cranberry or fuchsia powder for your magenta layer, you're not likely to get enough color saturation to yield a decent CMYK look. My experiments are being done with transparent enamels.

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Re: CMYK color separation

Postby Morganica » Fri Jul 05, 2013 5:07 pm

I think overall the enamels will give you richer color than the powder in such small dots. The volume of powder you need to apply to a dot to get well-saturated yellow or cyan is probably more than the dot's footprint can support. You may wind up needing multiple firings to get the depth of powder color you really need to simulate process color ink, and that could get you into registration issues. BE Yellow would be the big issue; Marigold Yellow is a bit more saturated (although it has probably more red overtones than you want), so you might try that.

I think the magenta actually would be the best of the bunch. My 1-lb jar of BE Cranberry Pink powder is nearly 20 years old and still a quarter full (and I split it 50-50 with a friend when I bought it), because it's such a strong color. A tiny bit goes a very long way in my work, so it's interesting, Val, that a MORE saturated magenta was a big deal for others at BeCON. Wow--it'd eat up the world.

I wonder if Stacey Smith has done much with this? Seems like it'd be right up her alley...
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Havi
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Re: CMYK color separation

Postby Havi » Sat Jul 06, 2013 3:53 am

I thought I was the only one in the world who was seeking to acheive a good magenta....
Now I realise I am not the only one, but belong to a wide group.

So,
What's the bottom line? is there a formula to create magenta? Will it be powders or frit no. 01?
What would you mix???


Grateful in advance,

Havi
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Valerie Adams
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Re: CMYK color separation

Postby Valerie Adams » Sat Jul 06, 2013 9:23 am

The message I left BECon with was this: there are so many colors still to be developed in the Bullseye palette that it's likely many of us will be waiting a long time for the specific colors we desire. So we were told by Dan Schwoerer, Sam Andreakos, and Ted Sawyer that "it's possible to create an almost infinite color range by mixing colors."

Judy Tuwaletstiwa and Erik Whittemore recently spent 15 months in Santa Fe layering and documenting hundreds of new color variations using Bullseye glass and powders. There's hope that their research and formulas will be available soon.

Havi wrote:So,
What's the bottom line? is there a formula to create magenta? Will it be powders or frit no. 01?
What would you mix???
Havi

Risa
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Re: CMYK color separation

Postby Risa » Sat Jul 06, 2013 11:13 pm

Thanks for the povs so far. This promises to be an interesting development project. I am starting with a very simple image, transparent BE powders and fine frits hand applied. I hope to figure out a decent set of colors to use, then move onto dry powder printing through screens. I do appreciate the comments about enamels vs powders and have a sample set from Thompson so I'll add some of those to my testing, too.

I am aware color saturation may be an issue with one firing so I plan to build a jig for screen/glass alignment for multiple passes. Because there will only be one color on each piece of glass, I will oversize the glass relative to the image to deal with registration of the layers.

Don, I appreciate your candor. I don't know a lot about the subtleties of the printing process. So this idea may indeed suck. Won't be the first time one of mine has....but if I don't have some failures I'm not pushing myself enough. Even (name your favorite athlete/team here) doesn't win them all. But I'm certain I will learn a lot and I appreciate this forum's help in this process.

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Re: CMYK color separation

Postby Morganica » Sun Jul 07, 2013 1:14 am

Valerie Adams wrote:The message I left BECon with was this: there are so many colors still to be developed in the Bullseye palette that it's likely many of us will be waiting a long time for the specific colors we desire. So we were told by Dan Schwoerer, Sam Andreakos, and Ted Sawyer that "it's possible to create an almost infinite color range by mixing colors."

Judy Tuwaletstiwa and Erik Whittemore recently spent 15 months in Santa Fe layering and documenting hundreds of new color variations using Bullseye glass and powders. There's hope that their research and formulas will be available soon.

They're right; any color you can mix in watercolor or acrylic you can probably reproduce with frit. I think I'm up to something like 7,300 pate de verre color samples, some as frit tints, some as layer sequences. It can become very complex--some of my pate de verre portraits have 30+ (really thin) color layers. I've been amazed at how different the samples look when I change the order or leave out a layer. Here's an example: In the first image, layer 5 is a thin sifting of Pimento Red, and the transparent deep plum sifting (shades the eyes and deepens the folds in the wrinkles) is at layer 14. In the second, they're reversed--everything else is the same. Notice that not only does the fleshtone change, but because pimento is an opaque glass, the light stops much sooner, too.
fleshsamples-may.png

This is what happens when I leave both the red and purple layers out, but everything else (including layer order) stays the same. (EDIT: Oops...I checked and these also lack the light sky blue at layer 12 (eyes/temples/inner nostrils/fingernails))
fleshsamples-noredpurple.jpg

The problem, though, is that I'm not really mixing glass colors, I'm placing one color in front of another and seeing through them, or viewing particles side by side (like a halftone, actually).

The fact that I've got a finite particle size means I need a certain footprint/volume (and viewing distance) for the color blend to show properly. Getting it to work in something as small as a halftone dot will be tough without some additional magic...which is why having a lot of pure colors right out of the jar is so important (and, actually, why my primary pate de verre glass will probably always be Bullseye--they simply have more colors to begin with).

In any case, the problem with frit mixes is that the trapped air between particles reduces transparency until you get the (wonderful, gorgeous, sighable) translucency of jade or alabaster, i.e., a pate de verre. The only way I've found so far to mix colors and retain transparency is to either layer sheet glass or recast billet multiple times.

OTOH, if you COULD get the process color method translated into glass, you've done all the color mixing you need to do. Sure would be nice...
Last edited by Morganica on Sun Jul 07, 2013 12:37 pm, edited 1 time in total.
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KaCe
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Re: CMYK color separation

Postby KaCe » Sun Jul 07, 2013 4:36 am

I am pleased to see this topic. It goes to ideas I've had knocking about in my head for years. I especially appreciate the examples shown and explanations. Excellent. I hope you'll post your experiences complete with images. Good luck.
=D>


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