I've been having trouble on a project here for a couple of days now. It's a mall circular design, about 7" diameter. it's a hand drawn piece, and the lines are pretty fine-somewhere between the sharpie ultra fine point and the standard sharpie line.
I'm having trouble getting all the lines to washout-several of them just seem to be getting exposed top light. I'm using a piece of glass to hold down the vellum during the exposure.
I'm not sure if I just haven't washed out the emulsion completely but in the places where it's stuck it looks like the same color as the rest of the exposed emulsion. So I'm thinking that somehow the thinner lines are being exposed.
Can I use a can of compressed air to blow the rest of the lettering out?
Should I re-do the screen, and before doing so, re-trace the art on the vellum to beef up some of the weaker lines?
Would it help if I shortened the exposure time a minute?
My exposure unit is a 250 watt Eiko photoflood lamp, hanging in a reflector about 12" above the screen. This worked fine for my first project (which featured bolder lines).
Not sure what screen I'm using-it's a Speedball screen I bought at a hobby shop. I don't have the art handy in my computer, the artist e-mailed it to the print shop for me, i picked it up there and we did a little touching up there to improve the contrast. it looks like he used a Sharpie fine line pen tho.
So, i should use a finer screen to get this to translate?
I was thinking that, due to the fine lines, I might benefit from a shorter exposure time, to reduce the chance of the lamp 'baking' the emulsion where it shouldn't?
I'm gonna pull some ink through the screen today, just to see if I'm having an optical illusion or not.
My exposure unit is a 250 watt Eiko photoflood lamp, hanging in a reflector about 12" above the screen. This worked fine for my first project (which featured bolder lines).
Not sure what screen I'm using-it's a Speedball screen I bought at a hobby shop. I don't have the art handy in my computer, the artist e-mailed it to the print shop for me, i picked it up there and we did a little touching up there to improve the contrast. it looks like he used a Sharpie fine line pen tho.
So, i should use a finer screen to get this to translate?
I was thinking that, due to the fine lines, I might benefit from a shorter exposure time, to reduce the chance of the lamp 'baking' the emulsion where it shouldn't?
I'm gonna pull some ink through the screen today, just to see if I'm having an optical illusion or not.
Thanks for any insight you can offer though.
Two things that could be causing your trouble come to my mind while reading your post;
-the speedball screen is probably not high mesh. I have some old speedball screens that I use for designs without high detail. If you need a lot of detail, you're going to have to get a higher mesh screen, like a mesh count of 155 or higher.
-Touching up lines on a positive with a marker could cause trouble, as the ink laid down by the marker won't be consistent, some areas are darker than others. A friend of mine wanted me to print a design that he drew on transparencies with a sharpee and it just did not burn well because of the inconsistent ink density.
Hope this sheds some light on your situation.
also dont use sharpies as they will not block the light correctly. Get yourself some Lithopaque pens. They will work perfectly.
I believe tubelight or Mel-Ray carry them. Im sure others do as well.
If you want to do artwork with sharpies do it on paper (rather than directly on the transparency) and photocopy it onto the film. That works well, but directly it doesn't.
Fine line artwork 
