Its all in the DETAILS!!!

Use an exposure calculation strip to determine your exposure.

Single point light source with a vacuum blanket helps too.

Screen mesh count and screen tension can also come into play.

Opacity of film also impacts your ability to resolve details.

The thickness of your emulsion on the screen .

All are factors in one's ability to make a screen and then print it with fine detail and / or small percentage dots.

You tell us what you are doing presently and we will be better equiped to offer suggestions instead of general comments...

tpope said:

You tell us what you are doing presently and we will be better equiped to offer suggestions instead of general comments...

Click to expand...

to start,
-i am using Text-P pure polymer emulsion

-on screens anywhere from 150 to 220 count. the 150 being a white screen, the 220 yellow.

-the emulsion is as thin as possible.

-the exposure box has 4 black lights and has a lid with sponge for contact.(no vacuum)

-i expose for about 45sec on yellow screen,
38sec on white.

-then i spray with water on both sides and let sit for 2minutes.

-then i washout the screen. ( i have noticed that sometimes i can see the detail on the design before washout and sometimes i can't.)

thats about it-
thanks guys

Yep... DETAILS...

The thin emulsion coating is one issue.
Here's an article dealing with coating screens...
Vector-Based Graphics Programs, by Douglas Grigar

Multiple point light sources create a softening or blurred effect onto your screen. This tends to undercut your small percentage dots and erase the. Likewise, poor contact between the film positive and the screen emulsion will also allow light leakage around the dots. Further, poor D max (how dark/dense is the film) will allow light to penetrate through the film positive and expose the emulsion underneath.

Soft edged dots and poorly defined line edges will also cause the screen to not carry all the detail that you put into the file. A 10X loupe will show this in your film positive.

Loose screens, runny inks, weak squeegees, no off contact, etc.... can cause loss of details...

You can not print dots that go from zero to 100 on most screen presses. They have real limits as to their ability to replicate the art that is provided.

Get and use an exposure calculator. Print the resulting screen onto a shirt and see just what you can do with your equipment. See if you can make a screen that carries a 5 percent dot. Print it and see how it grows. Try to hold a 05 percent screen open. See how it prints.

Measure and test. Record and learn. DETAILS! If it were easy... everybody would be doing it...

zack68ss said:

thanks for the info, im glad to see other people strive for excellence in their art!
i have some reading to do.
have you heard of a book called "screen printing for pleasure and for profit"?
it was recommended as the "bible" of screen printing.
if so do you recommend it?
or what other sources have you used that were helpful?
Thanks a bunch.
Zack

Click to expand...

Scott Fresener's book is a good starting point. I do not know what edition you have. It was first published in 1978. Much has changed since then.

Read everything available. So long as you can sort the good from the junk. You'll find snippets of gold in many articles and forum postings.

The hard part is telling the BS from the fact. The simple truth from the sales pitches.

You will not get it all right nor all wrong. There are many shades of grey (gray)... Accept and realize that your picture of an ideal print is different than your customer's.

You can approach your desired results through careful documentation of your efforts. What went wrong and what worked. Study the why...

Specialized schooling may be your best return on your money. I am not able to offer much here. The Grendel is one...

As Richard Greaves ( I hope that I have spelled this right) so often posts... WHAT ARE YOU MEASURING?

How to use an Exposure Calculator - Calibrated S.P.S. Screen Printing Supplies - Equipment

Did you use an exposure calculator?

Multiple lamps allows the light to undercut the positive. No vacuum means incorrect contact between the film emulsion and the screen emulsion and allows the light to undercut the image.

Think of it this way... Hold up a finger at arms length. Focus on a point out several feet away from you. That is you dot against the screen (finger) the image in background is your emulsion on the screen. Now move your head to the right slightly.. Then the left. You will see more of the background image (emulsion on the screen). This is what's happening when you have multiple light sources. They allow the light to peek around the dots on the screen and expose the emulsion. Then it does not wash out. Soft edged dots and low density films allow the same thing to occur.

All that said, you will find that no matter what exposure setup you have, you can only carry a certain sized highlight and shadow dot. You determine this with an exposure calculator.