# Half tones filling in...



## bsujoe (Jan 10, 2008)

Just wondering. We have output a tone at 45 lpi and at 50% and the finished print almost filled in. It was black ink and the printers are saying that is normal. I can't believe that is the case. What are we doing wrong. I know a simple solution is to lower it to 25% but how do you hold the tones better? Any secrets?


----------



## PositiveDave (Dec 1, 2008)

Sounds like they are getting some undercutting when exposing. A 'good' screenprinter should get from about 10-90% at least.


----------



## bsujoe (Jan 10, 2008)

The screens seem to be fine. It's the finished print. There is a lot of dot gain which I know happens but it seems like way to much. To gain 40% is to much.


----------



## APlusDesignsInc (Jan 27, 2016)

The rule of thumb I use for black halftones is to lower it 20% when you print the film. So if you want it to look 50% on the shirt, lower it to 30% on the film. This might need to be changed slightly as there are other factors that go into this. Screen mesh being another important factor. higher the screen mesh the less dot gain you will have. also the squeegee. The harder the squeegee the less dot gain. Hope this helps.


----------



## APlusDesignsInc (Jan 27, 2016)

Also, higher mesh count will hold dots better. We use 355 mesh for high detail and small dots.


----------



## gardenhillemb (Oct 29, 2015)

All of the above and also: sharp squeegie of at least 70 durometer. Keep your angle high and hit with a good, firm quick pull. This will help keep dot gain to a minimum while printing. You may also have to wipe the shirt side of your screen during printing to keep it clean.


----------



## williekid (Apr 22, 2009)

Squeegee angle, off contact and/or pressure possibly.


----------



## scubadog (Jan 5, 2008)

Also screen tension will make a difference!


----------



## PositiveDave (Dec 1, 2008)

Print a calibration strip - about 15 steps and check the prints against your films, you can estimate a calibration curve from that.
Remember that changing things will screw your calibration up, so changing the hardness or angle of your squeegee will ruin your settings...


----------



## bsujoe (Jan 10, 2008)

Good idea. That's a great place to start.


----------

