# Switching Emulsions from CCI DXP to Chroma Blue



## julzusc (Oct 29, 2007)

I just went to my supply shop and they were out of the emulsion I usually buy, CCI DXP. They told me to get Chroma Blue...and said it's exactly the same. 
I usually expose for 12 1/2 minutes, but I've been reading that Chroma Blue is a super fast exposed emulsion. 
Am I going to fry my screen exposing for 12 1/2 minutes?? Would you recommend I start there with my tests?? Or bring the time down a bit??


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## tlbays (Apr 9, 2008)

Hi Julzusc

Chemcon DXP is a dual-cure, if I'm correct.
That means there is a little bottle of sensitizer you fill with water and mix in before use.
This type of emulsion tends to be slower than one-part emulsions like the Chromablue from Chromaline.
The only thing that's really similar is the color.

If DXP=12min. for you, the Chromablue should fall between 6-8min.

At some point you may want to consider upping the wattage of your exposure unit, or moving the bulb(s) closer if possible.

Happy trails!


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## julzusc (Oct 29, 2007)

THANK YOU SOOOOO MUCH!!!!!!! I just exposed for 7 minutes and it washed out PERFECT!!! Wow! Thank you for the help!!!!!!


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## Spot_Worker (Oct 22, 2008)

Good shot Tom....


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## Crescent (Jul 25, 2009)

We recently switched from Ulano DLX to Chroma Blue, and can coat a lot more screens with a gallon of Chroma Blue, plus as you found out, it exposes in less than half the time. For short runs, we are only coating one side of the screen, so reclaiming is a little faster as well.


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## Ken Styles (Mar 16, 2006)

i love this stuff.
It's smooth, I am burning screens in 30 seconds flat and reclaiming is cake.


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## electroblake (Jan 5, 2009)

I'm switching from hobby grade Speedball Dizao emulsion (like you can buy in the arts and crafts store) to ChromaBlue and have the same question. I expose under a 150W metal halide lamp, about 15" between bulb and screen. I have been exposing the Speedball emulsion for 10-15 minutes for 300-80 thread per inch mesh. Should I just cut that in half?

Also, the guide says to work under a yellow lamp. Is red going to be ok? I would assume so since red is a longer wavelength than yellow but maybe this stuff's got a sensitivity spike in the IR - red range? (doubt it).

Thanks,
Blake.


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## tlbays (Apr 9, 2008)

Hi Blake

Yes, 6-8 minutes is a good starting point.
Be aware that potential pre-exposure is also faster than the dual-cure Speedball....
....but your red safelights are a more than ample for normal handling.

Note that the solids content of the Chromablue will coat slightly thicker than the Speedball.
On fine meshes (like 300T) you might also find better edge definition on image details.

Happy trails!


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## electroblake (Jan 5, 2009)

Thank you Tom! 

I was wondering about how this stuff would work with the finer mesh for fine detail. I'm just using 140 thread per inch now for a screen I'm going to use to print plastisol on shirts, but I also do fine art prints in acrylic on paper, and sometimes use screen printing enamels on metals. Any idea how well this stuff holds up? I know it's supposed to be great for plastisol. Should I just stick with the Speedball diazo for water based stuff?

Oh and I got a little impatient and went ahead and exposed my screen this morning. I planed on 7 minutes but didn't notice any color change (I guess maybe this stuff doesn't really change color) and let it go for 8. It all washed out but it took a bit of effort so I think 8 minutes was on the long side of acceptable. Still, it looks great! Thicker stencil than I usually get on the print side and smooth smooth smooth on the squeegee side. If the reclaimability is "excellent" like the guide says it is I think I've found an emulsion I'll stick with.

Thanks again,
Blake.


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## tlbays (Apr 9, 2008)

Hi again Blake

Note that the Chromablue is not recommended for use with solvent-based inks.

If your acrylics are water-washable, the Chromablue will suffice, but extended print runs with water-based inks often need their ChromaSet hardener for best durability.

There's another emulsion we'd recommend for broader "multipurpose" use if you wish to PM me for a sample.

You're correct about the exposure image "color change".
It's a characteristic of pure-photopolymer emulsions that is much less apparent than ones which employ a Diazo sensitizer.

Have a good day, I'm off to help out our local screen printers...


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## out da box (May 1, 2007)

How can I stop chroma-blue from closing in on fine halftones? I'm scared to go lower than 15 seconds, but the dots close up even at 15 seconds. Using a 400 watt m-h bulb 24" from the glass. Screens coated 2/1 round edge or 2/2 sharp edge- same results.


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## tlbays (Apr 9, 2008)

Hi Ridgely

What's your mesh count/color and what's the line count of your halftone?


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## out da box (May 1, 2007)

156 at 45 lpi, 230 at 45-55 lpi. 
I can do anything almost - 45lpi on 110 mesh with udc-2.
Just can't hold fine halftones with any sbq emulsion.


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## tlbays (Apr 9, 2008)

Here's something to consider.....

A dual-cure will allow more exposure time "elbow room" in its slower speed.

I'm guessing that your 230 mesh is dyed yellow, but your 156 is white? (it would be better for it to be yellow mesh also).
Have you ever tried a 255/40 for halftones?

You probably noted that the Chromablue has fewer pinholes than the UDC2. 
You can use this feature to your benefit and coat Chromablue screens with thinner emulsion layer(s).
It will resolve and allow easier development of the the finer patterns with that adjustment.

I have an account that coats an SBQ 1:1 (sharp coater edge/medium speed) on 350/30 and images 85dpi from about 3-5% up to 90%.

I certain you know that the film pos quality is very improtant in these instances.

Happy trails!


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## out da box (May 1, 2007)

Yeah, I'm starting to think my film isn't dense enough for the sbq and intense light source. Might start printing at 1440 dpi instead of 720 on the epson 4800.


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## tlbays (Apr 9, 2008)

Hi again, Ridgely

Good call........

Halftone dot edge quality improvements (set resolution to 1440 on the E4880) will help with either emulsions' ability to reproduce them.
It's much worth the longer printer output time it in this instance.

If you can get your hands on a loupe (magnifier 10-18X power) you'll see the dot edge quality increase in comparison.

Note that pure-photopolymer emulsions which cross-link on a finer scale will also be less "forgiving" on a poorly defined 20% 45dpi dot than a dual-cure/diazo formula.

This may be another aspect of your evaluation results, testing UDC2 vs. Chromablue.

Happy trails!


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## electroblake (Jan 5, 2009)

One more quick question about the Chromablue: Will any old stencil/emulsion remover work? I'm switching over from a production model where I have been re-stretching wooden frames to one where I will be re-claiming pre-stretched aluminum frames so I'm going to need to choose an emulsion remover. Do you have to use Chroma/Strip like the guide suggests?

Thanks,
Blake.


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## electroblake (Jan 5, 2009)

Ridgely,

I'm not sure if it's the same with the E4880 but with my Epson 1400 I get much much thicker ink deposits by setting the print setting to "photo RPM" and unchecking "high speed" in the print dialogue. In the MacOS 10.6.1 print dialogue box drop the middle menu down to "Print Settings," set "Mode" to "advanced," "Print quality" to "PhotoRPM" and uncheck "high speed."

Blake.


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## out da box (May 1, 2007)

Blake you shouldn't need special emulsion remover- anything should work fine.


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