Halftones

brooks · December 19th, 2007, 01:20 AM

Would a modified work light, two 500 watt bulbs, expose halftones?
(Shooting from below, distance yet to be determined)

thanks
-enough juice

SkyLinePrints · December 19th, 2007, 09:10 AM

short answer: yes

long answer: i do not believe the half tones will develop to their full potential. you will probably have some that come out clean, some that are crappy, and some that dont expose at all. Typical work lights do not have the light spectrum needed to really cure the emulsion and get fine details.

the distance from the screen will have an impact. you are going to need to play around with that to get the proper distance for exposures. also, when you say 2 500 watts, if they are mounted seperately, you could have a problem with some areas over exposing and others under exposing. I've read several postings with people having just this type of problem so be aware if it comes about.

once you have it all setup, you will need to do a Step Wedge test to get a good accurate calculation of your exposure time. your ink supplier should have the required components for this test.

Good luck and let us know how it goes.

Greg hamrick · December 20th, 2007, 08:48 AM

You should listen to what Nathan says about "Developing Half-Tones to their Full Potential".

I read in your other post that you know something about electricity and carpentry. Since you do...go to Lowes or Home Depot or where ever you can find grow lights. Get six of the 250 watt "Flood Light Bulbs"...then get those cheap ceramic fixtures. put them into a box no less than three feet deep and you'll have a 1500 watt "UV" producing light source. It will work much better than those lights you've been trying to use, mainly for the fact worklights work more in the "Infared" end of the sectrum.

Good luck and I hope you make that dead-line.

jr_sanford · February 12th, 2008, 06:39 PM

What I believe works best is the following:

a) A single filament light source (1000 watt metal halide would suffice).

b) A clean / clear vacuum table.

c) An emulsion able to perform to your needs. Aquasol HV® is an emulsion that I use and am totally delighted with it's performance.

d) Running a rope over the frame edge into the screen (around the exposure area) and over the opposite side, then exposure.

e) Of course - high opacity film images that you are using for art.

f) A mesh fine enough (I'm getting away with 137) to be able to display the halftone in all it's luster.

I believe that multiple light sources (filaments) can cause "undercutting" and "scatter" resulting is fuzzy stencil edges. To prove this, look at a shadow of your hand using one, then two flashlight light sources. You'll get the idea when you see the penumbra(s) exaggerated that way.