[alexD]

So below are a couple pictures of my first attempt with halftones. Overall I think it went much better than I expected!

The most obvious problem I had was washing the screen out. I blew a good chunk of the halftones out in the lower right corner of the face. I am thinking it might be because of underexposure.

Now I have only been into screen printing for about 6 months now but I have been practicing and reading up on information practically everyday. And I only did this as a learning experience. But I was hoping to get some advice for my next attempt.

I think my main problem was underexposure. I have a 500 watt halogen light attached to a stand I built made out of pvc pipes. Very similar idea to the one ryonet sells for $50. Nothing fancy at all. Normally, my exposure time is 13 minutes. I used speedball emulsion on this screen. I exposed this screen with halftones at 10 minutes. I've read on numerous occasions to lower your exposure time when dealing with halftones. Then wash out carefully and then double expose the screen outside or whatever. Now I am using a 110 mesh screen with the halftones set at 25 lpi. Maybe if I give it an extra minute or so?

Like I said, I am just practicing my skills and learning! Any advice and/or comments are greatly appreciated! Thanks all

 

[W.E. Productions]

I think you should use a higher mesh for half-tones because you need smaller holes in your screen for more detailed designs. I started out using the halogen light but moved up to using the yudu machine as an exposure unit when someone was selling one for a cheap price. I noticed a big difference with my screens and it was easier to wash out my designs using a garden hose with the sprayer set on shower. I use Ryonet WBP Hybird Emulsion and it works just fine for me. I like it because I use both water based & plastisol inks and it works with both. Good Luck!
​

 

[TYGERON]

I am thinking it might be because of underexposure.

Now I have only been into screen printing for about 6 months now but I have been practicing and reading up on information practically everyday. And I only did this as a learning experience. But I was hoping to get some advice for my next attempt.

First off, that's a scary picture.

Second, the underexposure is probably correct.

You don't necessarily lower your exposure times just because you're doing halftones. What you do calculate your most effective times with a one step exposure calculator. Times vary according to light source, mesh count, emulsion type, line count and a host of other factors.

Intentionally underexposing then re-exposing can work but you're needlessly inviting disaster.

Halftones don't mean 305 mesh 65 line. Big dots and coarser mesh work and are a bit easier to burn.

Get a calculator and follow the directions for using it and get in the habit of using it often. Conditions change, light source ages, humidity etc.

 

[alexD]

Excellent! Thank you!

haha I know its a creepy picture. It is for a really fast and aggressive band. It suites them well haha

I can't wait to try again!

 

[TYGERON]

Excellent! Thank you!

haha I know its a creepy picture. It is for a really fast and aggressive band. It suites them well haha

I can't wait to try again!

Post back your next result after dialing in your times. Like I said, getting accurate times can save a lot of time and effort.
What kind of film are you using? Clear film allows faster exposure than vellum. And make sure the film is in as close contact with the screen as possible.
A firm, insistent, tap temperature spray should suffice for washing out. Tight screen, opaque ink, sharp squeegee, a bit off contact, fill stroke then low angle print single pass so the ink lays on top (not into) the fabric and you should be good to go.

 

[TableSyrup]

Bahahahhaaaa. I hope my next halftone attempt isn't as scary as her! I'm going to have nightmares

Hahahhaaaa. Looks like yer on yer way tho - a little better than my first attempt was.

 

[TYGERON]

Aw, man.

I was in Minneapolis over the weekend. More like for a few hours.

If I'm back I'll hit you up!

 

[TableSyrup]

Do it! I could pay you for a training session! Hahahaha

When I got back from LA in January, I was sooooooo mad to find out that I was actually in Long Beach during ISS but had no idea!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Grrrrrrrrrrrrrrrrrrrrrrr

 

[TYGERON]

Do it! I could pay you for a training session! Hahahaha

Haa-haaa!

What we need to do is start a "Pimp My Press" business .

 

[bluemoon]

So below are a couple pictures of my first attempt with halftones. Overall I think it went much better than I expected!

The most obvious problem I had was washing the screen out. I blew a good chunk of the halftones out in the lower right corner of the face. I am thinking it might be because of underexposure.

Now I have only been into screen printing for about 6 months now but I have been practicing and reading up on information practically everyday. And I only did this as a learning experience. But I was hoping to get some advice for my next attempt.

I think my main problem was underexposure. I have a 500 watt halogen light attached to a stand I built made out of pvc pipes. Very similar idea to the one ryonet sells for $50. Nothing fancy at all. Normally, my exposure time is 13 minutes. I used speedball emulsion on this screen. I exposed this screen with halftones at 10 minutes. I've read on numerous occasions to lower your exposure time when dealing with halftones. Then wash out carefully and then double expose the screen outside or whatever. Now I am using a 110 mesh screen with the halftones set at 25 lpi. Maybe if I give it an extra minute or so?

Like I said, I am just practicing my skills and learning! Any advice and/or comments are greatly appreciated! Thanks all

not bad for a first try! You have some pretty clean half tones there and the image has good definition. It makes a great starting point!

my first thought would be to expose it twice as long as you did and use a pressure washer to blow it out. Good setup will hold up to the pressure.

Also, as mentioned already, make sure your film is tight against the screen while exposing. I think those are going to be your two most important factors, correct time and good film contact.

post more pictures and ask more questions and we'll help!

pierre

 

[Preston]

I think my main problem was underexposure. I have a 500 watt halogen light attached to a stand I built made out of pvc pipes. Very similar idea to the one ryonet sells for $50. Nothing fancy at all. Normally, my exposure time is 13 minutes. I used speedball emulsion on this screen. I exposed this screen with halftones at 10 minutes. I've read on numerous occasions to lower your exposure time when dealing with halftones. Then wash out carefully and then double expose the screen outside or whatever. Now I am using a 110 mesh screen with the halftones set at 25 lpi. Maybe if I give it an extra minute or so?

Actually very good for your first try and yes the problem was more than likely underexposure.

The biggest obstacle you are going to have is the 500 watt halogen light. These light put off very little UV light in the correct nanometer range. This makes if very hard to control correct exposure times as any change in the amount of emulsion, the humidity, the temperature can throw off what you thought was a perfect exposure time so repeatability becomes almost impossible. Also those light put of a lot of IR radiation that can heat up the emulsion on the screen so much that you get inconsistent screens.

For around 50 buck you can find 400 watt Metal Halide high bay lights on Ebay. Metal Halide puts out a lot of UV light in the correct nanometer range needed to expose screens. Even a 100 watt Metal Halide light will exposure your screens in about a 1/3 of the time it takes you now with the halogen light.

Good film to emulsion contact is also a must. The best is using a vacuum to compress a rubber blanket over the screen but even a compression system using foam will work as long as you do not have any warped screens.

A real cheap way is to just get a space bag. Put a piece of foam covered with black fabric in the ink side of the screen. Put your positive on the shirt side. Stick it in a space bag and pull a vacuum with a shop vac. Now cover the side with the film on it with a black cloth or black painted piece of cardboard (outside the space bag). Now walk out into the sun, remove the cloth or cardboard, count about 20 seconds and the cover it back up and go back inside.

With a properly exposed screen you should be able to wet the ink side, lay it face down, pool water on the shirt side and the unexposed emulsion should just start to fall out in just a very short amount of time. Then just finish rinsing with a garden spray nozzle.

I know some people like to over expose and then blast with a pressure washer but a properly exposed screen will just wash right out with very little water pressure. When you can just rinse it out and hold all the detail, you know you have it right.

 

[Bernzomatic]

I'm totally new to screen printing. Actually started about 3 weeks ago, hah. Anyway, your set up sounds exactly like mine, mesh size, speedball emulsion, 500 watt halogen, normally a 13 minute exposure time, etc.. I just attempted my first halftone print and it actually came out really well in my opinion, much better than I expected. I figured maybe I could help you out;

My light is set 18 inches away from my screen and is exposed (and timed w/ 2 timers) for 13 minutes. I rinse my screens with the shower head so it's not too much pressure but the screen cleans out very quickly and without error. I use the 13 minutes for both my standard prints as well as halftones (at least the one I've done so far) I also have my halftones set at 25lpi.

My advice is to try again and expose your screen for 13 minutes as usual.

Hope this helps!

(I would also love to hear any advice anyone has for me based on my pictures! Thanks!)

 

[TYGERON]

Those coarse dots give a very graphic look. If you haven't already, you should try squares and lines also.

How did you determine 13 minutes as your exposure time?

 

[Bernzomatic]

Those coarse dots give a very graphic look. If you haven't already, you should try squares and lines also.

How did you determine 13 minutes as your exposure time?

I just tried using squares and lines, but I didn't think they looked very good. Hm..

I've been meaning to do a step test to acquire the perfect exposure time, however in reality it's all just been guess work as of now. Originally when I started I was using a standard 75 watt household bulb to expose, haha, yeah I know. So when I finally upgraded to a 500 watt halogen I followed what Ryan said on Ryonets starter kit DVD. He said using a 500 watt halogen placed 18-20" away you should expose your screen for 13 minutes. Gave it a try, and it's been working great.

 

[alexD]

Bernzomatic, Thank you! I think we are in the same boat as far as our equipment and thats looks great. A little longer exposure will work hopefully.

Might look into a new light too!

I should get around to trying this again this week!

 

[DedMan]

The more "photographic" you want the print to look the higher resolution and mesh counts you will need to use. Unless the customer wants a coarse dot our half-tones are usually 45-55 lpi this puts them in the same realm as Newspaper photos. Printing these through a 230-305 mesh gives you a photographic looking print while still having decent washability. I've done 65 lpi through 355 mesh in the past and while it looked great with sharp detail, after a couple washings it started fading pretty quick.
You can make an exposure guide by printing out a positive that has a halftone scale on it in whatever resolution you're using. We use a rectangle that goes from 100% down in 5% increments.
Hope this helps

 

[TYGERON]

Originally when I started I was using a standard 75 watt household bulb to expose, haha, yeah I know. So when I finally upgraded to a 500 watt halogen I followed what Ryan said on Ryonets starter kit DVD. He said using a 500 watt halogen placed 18-20" away you should expose your screen for 13 minutes. Gave it a try, and it's been working great.

Bro, I started waaaay back with a 150 watt bulb, 12" above the screen with an aluminum pie pan reflector. 45 minute exposure time for 110's. Speedball emulsion and I burned some pretty good detail and halftones! Occasionally stepped up to sunlight at about 20 seconds (weather permitting).

Try a single step calculator though. One step. Saves time. 13 minutes won't be the same for higher and lower mesh counts.

 

[TYGERON]

Achieving smoother tonal transitions and more detail will often require adjustments to the photo (contrast, brightness, darker areas, midrange, tone curve and dot gain adjustments) in addition to just finer mesh and higher line counts.

Printing a smaller dot and getting sufficient coverage, you press harder, dark areas get darker due to dot gain and detail is lost. So over all it's a delicate balance and combination of image prep, set up and technique to get adequate results.

 

[Bernzomatic]

Bro, I started waaaay back with a 150 watt bulb, 12" above the screen with an aluminum pie pan reflector. 45 minute exposure time for 110's. Speedball emulsion and I burned some pretty good detail and halftones! Occasionally stepped up to sunlight at about 20 seconds (weather permitting).

Try a single step calculator though. One step. Saves time. 13 minutes won't be the same for higher and lower mesh counts.

Haha yeah, I found 1 hour to be a sufficient exposure time with my 75 watt bulb w/ reflector. I'm actually using Speedball emulsion as well and have not had any problems as of yet. I may try something different when I run out.

I'll definitely give it a try, thanks a lot!

 

[IS STUDIO]

Ok here's a question regarding halftones. I'm printing an intricate logo design, the vector letter form is masked with carbon fiber texture and has a stroke around the piece. I'm printing the logo in grayscale with a 305 screen -the positive adjusted to 25% dot gain at 60 lpi . The problem is the opaque sections are not fully opaque and of course after several strokes the image loses highlights and res. So I tried adding a white underlay and then printed the black layer on top. The opacity was better but not perfect. I was wondering if reprinting the positive with less dot gain would render better results or should I step down to a courser mesh? Or both? I've also read that some people sep out a highlight layer and print that on top of the black layer? Or should I do both and use an underlay, a black layer and a highlight layer?